IFI Policy Recommendation No.32

June 2024

Transforming human systems tosafeguard the Global Commons
An integrated assessment of deep transformations
in human energy, land use, and production andconsumption systems towards keeping the Global
Commons within the safe space of the Planetary
Boundaries
Center for Global Commons
Institute for Future Initiatives, The University of Tokyo

Policy recommendation on transforming energy, land use, production andconsumption to safeguard Global Commons
If transformative changes in energy use, land use, production and consumption patterns were
implemented jointly, the climate, ice cover, oceans, ozone layer and land biosphere could all
be safeguarded together, maintaining the integrity of the Global Commons, and keeping
within the safe space of the Planetary Boundaries. The new Global Commons Stewardshipreport is a joint work of the Center for Global Commons (CGC) and Potsdam Institute for
Climate Impact Research (PIK). It delivers an integrated assessment of the effects of thosetransformative changes and how they interact with each other.
Human activities have already pushed several planetary systems beyond the safe operating
space defined by the Planetary Boundaries. Transformation of human activity and systems
would allow for a reversal of this degradation of Global Commons – the shared resources thatenable well-functioning ecosystem services – to levels very close to or within the Planetary
Boundaries by 2050. Key measures include rapidly decarbonizing the electricity sector via
renewable energy, electrifying public transport, shifting towards sustainable diets, cutting
food waste by half, and enhancing material efficiency within the steel, cement, and chemical
sectors. The report finds that an integrated, comprehensive design of policies is needed tosafeguard the Global Commons effectively.
This report is the most recent iteration of collaborative efforts under CGC’s Global Commons
Stewardship Initiative, launched in 2020 with international partners.
Transforming human systems to safeguard the Global Commons:
https://cgc.ifi.u-tokyo.ac.jp/wp-content/uploads/2024/03/GCS_report_2024.pdf

Transforming human systems tosafeguard the Global Commons
An integrated assessment of deep transformations in human energy, land use,and production and consumption systems towards keeping the Global Commons
within the safe space of the Planetary Boundaries

March 2024

1

This report was prepared by the Potsdam Institute for Climate Impact Research (PIK) and the Center
for Global Commons (CGC) at the University of Tokyo. The analysis and report production were
undertaken by Gabriel Abrahão, Dorothee Keppler, Simón Moreno, Isabelle Weindl, Jessica Strefler,
Bjoern Soergel, Lavinia Baumstark, Christoph Bertram, Michael Crawford, Jan Philipp Dietrich, Alois
Dirnaichner, Robin Hasse, Jens Heinke, Florian Humpenöder, David Klein, Gunnar Luderer,
Christoph Müller, Michaja Pehl, Robert Pietzcker, Franziska Piontek, Alexander Popp, Sebastian
Rauner and Renato Rodrigues, under the direction of Elmar Kriegler (PIK), Johan Rockström (PIK)and Naoko Ishii (CGC).

Please cite this report as:
Abrahão et al. 2024. Transforming human systems to safeguard the Global Commons: A report by PIK
and CGC. Potsdam, Germany and Tokyo, Japan.

The Global Commons Stewardship Project
The Global Commons Stewardship (GCS) project, initiated and led by the Center for Global
Commons (CGC) at the University of Tokyo, in partnership with PIK, SDSN, WRI and SYSTEMIQ,
aims at the development of a conceptual framework and strategies for Global Commons
Stewardship.
Within the GCS project, the Potsdam Institute for Climate Impact Research (PIK) is responsible for
conducting interdisciplinary modelling, performing a comprehensive assessment of how thesystem transformations identified in the GCS project can contribute to the stewardship of the
Global Commons.

The Global Commons Stewardship Framework2

Contents
The Global Commons Stewardship Project2
Executive Summary
6
Current policies and the Global Commons
6
A holistic transformation pathway
6
Modelling transformations
9
Effects of individual transformations
10
The role of demand reductions
11
Industry transformation
12
Policy recommendations
13
1. Introduction
16
2. Implemented policies and current commitments
19
Motivation and Methods
19
Key findings
19
Effects of implemented policies (NPi) and current commitments (NDC) scenarios on the
Global Commons domains
20
3. Transforming Energy Systems
22
Motivation and Methods
22
Key findings
23
Effects of the Energy Systems Transformation on the Global Commons domains
23
4. Transforming the industry sector
27
Motivation and Methods
27
Key findings
28
Effects of the Sustainable Production and Consumption Transformation on the Global
Commons
28
GHG emissions from the global industry
29
Transformational challenges
32
Circularity push35
5. Transforming Land Systems
38
Motivation and Methods
38
Key findings
40
Effects of the Land Systems Transformation and its components on the Global Commonsdomains41
6. Synergies, trade-offs, and alternative socioeconomic assumptions
45
Motivation and Methods
45
Key findings
45
References
65
Annex
67
Annex 1: Model descriptions
67
Annex 2: Indicators used for the Global Commons domains
70
Annex 3: Assumptions and interventions used to implement the four systemtransformations in REMIND-MAgPIE
71

3

Executive Summary
Current policies and the Global Commons
Safeguarding the Global Commons requires a global perspective. The Global Commons, thebiophysical systems that as a whole keep the Earth System stable and resilient, consisting of several
global commons domains, are the foundation of human development and prosperity. Currently,
human activities have already pushed several of these systems outside the safe operating space of
the Planetary Boundaries.
Our integrated assessment results show that, with current policies, humanity is on track to worsen
the state of most Global Commons domains and cross several Planetary Boundaries by mid-century(Fig A). The boundaries for Nitrogen Flow, Land System Change and Biosphere Integrity have alreadybeen transgressed today, and continuing current policies would not reverse the underlying trends by
returning the associated indicators to a position substantially closer to their Planetary boundaries by
2050. With just the controls currently in place on emissions of CO2 and other greenhouse gases, thePlanetary Boundaries for Climate Change and Ocean Acidification would also be crossed by 2050.1
The only indicator that is set to improve is the one for the Ozone Layer, with the successful
implementation of the Montreal Protocol bringing ozone depletion back inside the Planetary
Boundary.
A complete worldwide implementation of the Nationally Determined Contributions (NDC) on
emissions reduction, land protection and afforestation by 2030 and the continuation of this level ofambition until 2050 would not substantially change the worsening trends under current policies.
Only small progress back towards the Planetary Boundaries for Climate Change, Ocean Acidificationand Land System Change would be made, which is not enough to remain inside the Planetary
Boundaries or even stop degradation at current values. Furthermore, the pressures of increased
land scarcity and a possible reliance on bioenergy for reducing emissions would lead agriculture tofurther worsen the state of the Nitrogen Flow indicators.

A holistic transformation pathway
A scenario in which transformations of energy use, land use, and production and consumption
patterns are implemented jointly would allow humanity to reverse the degradation of the Global
Commons domains to levels very close to or within the Planetary Boundaries by 2050. Althougheven these deep systems transformations would not be able to keep warming below 1.5°C without asmall overshoot in 2050, a combination of CO2 removal and continued reduction of non-CO2
emissions would revert warming, so that global mean temperatures would stay below the Paris
Agreement target by 2100 and beyond. However, CO2 concentrations and radiative forcing would still1

As described in Section 2.3, we define the Planetary Boundary as 1.5°C warming over the preindustrial value, the target set
by the Paris Agreement. As current warming is around 1.1°C, the target has not been crossed yet, but would be in 2050 if
current policies continue. In this point we deviate from the Planetary Boundaries framework (Steffen et al. 2015) which
defines Climate Change as an atmospheric CO2 concentration of 350 ppm. Based on this indicator and value, the Planetary
boundary for Climate has already been crossed, and even all the transformations investigated here cannot bring CO2
concentrations back below that value.

4

only be stabilized at around current levels, at which changes in climate harmful to human and natural
systems are already observed.
In the scenarios considered, the proposed interventions lead to dramatic changes in the energy,
land and production and consumption systems. In our modeling framework, these changes are a
combination of direct model assumptions and endogenous responses to them. Some of the most
relevant are:
●

●

●
●
●

●

●

The average global price on GHG emissions in both the energy and land sectors reaches
around 90 U.S. dollars per ton of CO2eq in 2050. These levels are relatively low, being
enough to limit warming to 1.5°C by 2100 (with limited overshoot) only in combination withall other transformations. Prices are phased in more slowly in developing countries. In theabsence of these other transformations, the prices required for the same temperature limit
are over three times higher.
Diets worldwide move towards more healthy and sustainable patterns, along the lines of the
EAT-Lancet diet recommendations, by 2050. Global consumption of livestock products,
which is currently increasing, decreases by around half, especially moving away fromruminant meat. Most of this reduction comes from developed countries with meat-rich diets.
Food waste is halved by 2050.
Global average crop nitrogen use efficiency (NUE), the fraction of nitrogen in fertilizer that istaken up by the crops, improves from the current 50% to 70%.
All areas currently listed as protected in the World Database of Protected Areas (WDPA) are
effectively protected, plus all intact forest landscapes and biodiversity hotspots, in total
protecting around 30% of the global land environment by 2030. This value is in line with thecommitments in the Kunming-Montreal Global Biodiversity Framework. GHG pricing isapplied to land use change to disincentive loss of carbon, natural vegetation and biodiversity
in non-protected areas.
The share of electricity in the global final energy supply increases from currently below 20%
to ~25% in 2030, to 45% in 2050. A combination of reduction in the cost of renewables andcarbon pricing leads to an almost complete phase out of coal and oil use in electricity
generation, and reliance on gas falls below 2% of the electricity supply in 2050.
The per-capita demand for cement is reduced by 20%, as a result of price changes in theenergy system and through the promotion of higher material efficiency in the buildings
sector.

5

Fig. A: Effects of the continuation of current policies (from 2015 to 2050, top row) and of varioustransformations (in 2050) on keeping the Global Commons domains within selected the Planetary Boundaries.
Inner dotted lines mark the Planetary Boundary value (or the 1.5C global mean temperature change limit in thecase of the Climate Change boundary). Green (red) arrows indicate an improvement (worsening) of an indicator
due to a certain transformation in 2050 in relation to either 2015 (blue lines in NPi) or to the current policies
continued scenario in 2050 (black lines). Wedges show the relative value of each indicator, with green (orange)
portions showing the part inside (outside) the defined safe space. The starting points of the wedges at thecenter were chosen so as to visually emphasize the effects and their relation to the Planetary Boundary value,
and are not comparable across indicators. Effects on the Air Pollution and Freshwater Use boundaries were notexplicitly quantified in this study.

6Modelling transformations
In this study, we used the REMIND-MAgPIE
integrated assessment framework to simulate
scenariosthat
implement
different
combinations of these transformations inaddition to existing policies. Results show how
they affect the future development of five
GlobalCommons
Domains,(Climate,
Cryosphere, Oceans, Ozone Layer and Land
Biosphere) relative to the Planetary Boundaries
over the course of the next century.
Due to the high relevance of the land andindustry sectors for the pressure on several
planetary boundaries, special sets of scenarios
also offer insights into the effects andtrade-offs
ofdedicated
landandindustry-specific transformations. In the land
sector, options for changing current foodsystems, improving resource efficiency inagriculture, and land-based solutions forclimate change were investigated. In theindustry sector, reductions in the demand formaterials, the introduction of carbon captureand storage (CCS) technologies, and widespreaduse of hydrogen were analyzed in combination
with GHG pricing in the sector. Additionally, thepotential of circular economy strategies in theplastics sector was examined in relation to the Fig. B: System Transformations implemented inplanetary boundaries of climate change and the the REMIND-MAgPIE modelling framework
introduction of novel entities.

7

Effects of individual transformations
Implemented individually, the transformations of energy use, land use, and production andconsumption patterns have different effects on safeguarding the Global Commons. Most but not allof them are positive.
●

The Energy Systems Transformation has strong effects on safeguarding the Climate, Cryosphereand Oceans, but can have detrimental effects on the Land Biosphere Global Commonsdomains. Transforming the energy systems towards sustainable energy sources and shifting
towards more sustainable transport modes would reduce GHG emissions by 39 Gt CO2eq/year in
2050, a 60% reduction relative to a scenario with only the currently implemented policies. This
would prevent around 0.19°C of warming. Most of the avoided emissions would be of CO2,
keeping Ocean Acidification at relatively safe levels inside the Planetary Boundary throughout
the century. However, an increased reliance on bioenergy ultimately has detrimental effects on
the Land Biosphere, leading to higher deforestation rates, use of nitrogen fertilizers, agricultural
consumption and degradation of biodiversity.

●

The Land Systems Transformation is fundamental for preserving the Land Biosphere, but also
has substantial positive impacts on the other Global Commons domains. By 2050, it would halt
the loss of natural forest, reduce agricultural water consumption and improve human-induced
nitrogen fixation and biodiversity intactness to conditions superior to those of today. This would
bring Land System Change, Nitrogen Flow and Biosphere Integrity back within their Planetary
Boundaries. These effects are more than enough to counteract negative effects from the Energy
Systems transformation in these Global Commons domains. The combination of landinterventions would also reduce GHG emissions by 19 Gt CO2eq/year. Methane emissions would
be particularly reduced, preventing 0.18°C of warming in the medium term (2050) andminimizing overshoot of the 1.5°C Paris Agreement target. The avoided CO2 emissions would
have positive impacts on Ocean Acidification, but not enough to prevent it from degrading tolevels outside the Planetary Boundary.

●

Individual components of the Land Systems Transformation focusing on resource-efficient
production, reduction of GHG emissions, and dietary changes, differ in terms of their individual
impact on safeguarding the Global Commons domains, and exhibit synergies and tradeoffs
between them and with other transformations.
○

Transitioning to resource-efficient production systems is a key supply-side intervention to
reduce human-induced nitrogen fixation and agricultural water use. However, reducing water
consumption by limiting irrigation can increase pressures on Land System Change andBiosphere Integrity, as replacing irrigated systems with relatively lower-yielding rainfed ones
requires more land area.

○

Pricing GHG emissions from land use change can prevent leakage effects from otherinterventions, including those that can occur if regulation-based land protection orafforestation schemes like current NDCs miss sufficient coverage in terms of regional
distribution and types of included ecosystem.

○

Each of these land protection measures are of paramount importance if interventions inother sectors further increase biomass demand, e.g. for energy use. On the other hand,
8land-based solutions alone can push unsustainable intensification practices and can create
tradeoffs with water use.
○

In contrast, transforming food demand towards more sustainable diets and reducing foodwaste leads to strong beneficial impacts across most Global Commons domains. It can
combine synergistically with other land interventions, leading to more than additive
outcomes in Land Systems Change and Biosphere Integrity, as reduced demand for foodfrees more land to be used for mitigation and conservation. Its beneficial effect on reducing
emissions and the use of nitrogen and water are slightly diminished when evaluated inconjunction with the other land interventions, which ultimately make the food system moreenvironmentally efficient and therefore reduces the burden of additional food demand.
However, it still positively affects economic variables such as food and bioenergy prices,which are mostly negatively influenced by the other land interventions. It is also key tofacilitating a multi-dimensional transformation to sustainability that also addresses humanwell-being and development.

●

The Sustainable Production and Consumption Transformation has some effects on safeguarding
the Climate, Cryosphere and Oceans, but is not enough to protect them on its own. The
improvements in material efficiency and more sustainable consumption habits ultimately lead tolower industrial production and energy demand, which reduces GHG emissions by 16 Gt
CO2eq/yr relative to current policies in 2050. These reductions can prevent 0.09°C of warming
overshoot in 2050 and have benefits for Ocean Acidification. When combined with othertransformations, Sustainable Production and Consumption can further limit peak warming,
facilitate the Energy Systems Transformation and ease the pressure on the Land Biosphere.

●

The transformations have little to no effect on the Ozone Layer beyond the Montreal Protocol.
With continued compliance to the Montreal Protocol on the emissions of ozone-depleting
substances, the ozone layer should return to pre-1980 levels between 2030 and 2050.

The role of demand reductions
Interventions that reduce demand for goods and services, be it for industrial materials (such as theSustainable Production and Consumption Transformation), or for unsustainable food products(Sustainable Food demand) can have very substantial effects on safeguarding the Global Commons.
But even within our deep transformations, demand-side interventions alone will not be sufficient
to reach any of the assessed targets. Furthermore, when coupled with structural changes in thesystems themselves, such as the decarbonisation of energy supply and more resource-efficient
agricultural production, these demand-side interventions tend to have a smaller effect than when
considered alone. This arises from the fact that these transformed production systems can fulfill thesame demand with less impact on the Global Commons.
However, reductions in demand can be fundamental in reducing the socioeconomic burden ofthese production systems transformations, making the same targets achievable with lower prices
for food, energy and GHG emissions for example. Since most of the demand reductions assessed
require deep behavioural changes, implementing them is posing a major policy challenge.

9

Industry transformation
Industry-specific modelling shows that carbon pricing is essential for reducing the sector’s
environmental impacts, but implementing industry-specific policies enables faster and deeper
de-carbonization of the sector.
Reducing the material demand of the economy through sustainable production and consumption
practices offers significant reductions of the pressure that industry puts on the Global Commonsdomains. However, the feasibility of deep dematerialization remains uncertain.
Carbon capture and storage (CCS) is important for deep decarbonization of the global industry totackle process emissions, as these cannot be mitigated by means of low-carbon energy carriers.
However, CCS technology is not a viable replacement for phasing out fossil fuels for energy use.
Robust policy making for deep decarbonization cannot be avoided.
The adoption of hydrogen-driven technologies in the industry sector should concentrate on thespecific applications where electrification is not feasible, as it is generally not the most cost-effective
solution .
Circular approaches for plastic waste mitigation can help mitigate the introduction of novel entities
in the earth system while avoiding putting further pressure on the climate and the energy transition
but further research is required that defines the technical, economic, and environmental limits of thisalternative.

10

Policy recommendations
An integrated, comprehensive design of policies is needed for a Global Commons stewardship:
Global Commons stewardship needs combined and comprehensive policy settings, targetingtransformations on multiple sectors at the same time. To protect and preserve the Global Commonsand planetary integrity, such an integrated approach is of utmost importance. The interventions
considered in our scenario analysis are mutually supportive in preserving the Global Commons inmany cases, and can avoid or compensate for policy trade-offs if applied together. This is of particularimportance between and within the Energy and Land Systems Transformations, to avoid trade-offs
between land-based mitigation, growing bioenergy crops and nature conservation.
Current policies and commitments need to be substantially strengthened and increase theircoverage of the broad set of changes and transformations required for safeguarding the Global
Commons: Current commitments should not only be implemented, but strengthened with more
ambitious targets in terms of emissions reductions by 2030 and 2050, but also of land andbiodiversity protection. The recently adopted Global Biodiversity Framework represents a major stepin this direction. Policy measures should also have a more comprehensive focus on multiple sectors
and producer and consumer-facing interventions. This could help fill gaps in policy coverage, forexample, with regard to better taking into account the effects of agricultural systems on the waterand nutrient cycles, inducing a change towards more sustainable consumption patterns, andincreasing the material efficiency of production.
An emissions pricing scheme to safeguard the Global Commons should play a critical role topenalize actions that lead to more GHG emissions and reward those that reduce emissions. It
should be designed to cover all emitting sectors, have prices that rise over time, and explicitly
address its own equity and distributional impacts: Measures that effectively put a price on emitting
GHGs can have large positive effects on many Global Commons domains. Actual measures can
include direct carbon pricing or taxation, but also carbon markets (such as the EU Emissions Trading
Scheme) or regulations. Emission pricing directly targets the protection of the climate, and thus also
the preservation of ice sheets and glaciers and the prevention of further Ocean Acidification. It also
discourages the use of coal and other fossil fuels, thus improving air quality especially in cities andcommunities. Including the land use sector in such a pricing scheme creates incentives to protect andexpand forests. It also disincentivizes an excessive reliance on bioenergy for decarbonizing theenergy sector. Including GHGs other than CO2 in the pricing scheme also favours less meat
consumption and fosters a more sustainable use of nitrogen fertilizers. However, GHG pricing shouldbe accompanied by specific land protection measures to alleviate the pressure that some climate
mitigation options such as bioenergy use and afforestation can cause on natural and semi-naturalland, which is critical for halting and reversing biodiversity loss. GHG pricing instruments should
address their equity and distributional impacts by design to ensure their acceptance, directing theirrevenues to lower income regions and households and phasing in prices more slowly in developing
countries.
The GHG price levels required for safeguarding the Global Commons domains, especially the
Climate, depend crucially on all other measures implemented: In the absence of any othermeasures, energy system GHG prices in our scenarios would have to reach around 350 U.S. dollars
per ton of CO2 equivalent by 2050 to reach the 1.5°C climate goal. Combining it with other policies,
11especially encouraging the reduction of total demand for high emissions products and services,such as industrial materials, energy and animal-source foods, and pricing emissions in the land
sector lowers the GHG prices necessary to achieve the same climate target. Demand reductions,although difficult to implement, ease the cost of transition and have several co-benefits for the land
biosphere. Combined with strong levels of demand reduction, a comprehensive GHG pricing scheme
in the energy and land use could achieve the 1.5°C climate goal with prices as low as 90 U.S. dollars
per ton of CO2 equivalent by 2050.
The role of bioenergy in decarbonising the energy system should be limited and coupled with landconservation policies: Bioenergy production can lead to severe trade-offs, threatening the integrityof the land biosphere and increasing food prices. Many of these effects could be counteracted byvery ambitious conservation policies and a shift towards more sustainable food consumption
behaviour, which are challenging to implement at a global scale. Therefore, a mix of regulations onenergy markets to limit their reliance on bioenergy and comprehensive conservation policies on
bioenergy producing regions is recommended.
Foster sustainable production and consumption of industrial goods: A reduction in per-capita
production of material goods in high-income countries facilitates the decarbonization of the energy
supply, thus contributing directly to the protection of climate, cryosphere and oceans, as well as to a
reduction of air pollution and associated health effects and the amount of waste to be disposed of.
Part of these reductions can be achieved through material efficiency measures and technologicalimprovements in the producing industries. But promoting a shift to more sustainable consumption
patterns, with a focus on sharing and circular economies, could also lead to massive benefits.
A sound strategy for the sustainable transformation of the global industry requires a set of
sector-specific policies to overcome potential bottlenecks and carbon lock-ins. Incentives thatspeed up the development and rapid scale-up of Carbon capture and storage technologies areneeded to mitigate process emissions in industry. However, deploying CCS is not a license tocontinue to use fossil fuels, as it cannot provide full decarbonization. Robust policy making for theindustry transformation should hedge against the deep uncertainties underlying both newtechnologies and reductions in demand. More research must be done to define thetechno-economic boundaries of dematerialization and material efficiency, as well as advancing theunderstanding of cross-sectoral interactions. Incentives that foster the scale-up of hydrogen areneeded, but should be targeted to applications where electrification of processes is technicallyconstrained. Subsidizing the deployment of hydrogen beyond the necessary scope risks triggering
additional transformational challenges which can hinder the transformation of industry.
Promotion of healthy and sustainable diets and a reduction of food waste: The food system is oneof the key drivers for environmental degradation. A transition to lower meat and dairy consumption,
as recommended by the ‘Planetary Health’ diet of the EAT-Lancet expert commission, improves
human health and has far-reaching positive consequences for the Global Commons. Together with areduction of food waste, an adoption of the Planetary Health diet reduces food sector emissions of
CH4 and N2O drastically. By reducing land requirements for food production, in addition to inputs for
agriculture such as irrigation and nitrogen fertilizer, sustainable diets are key to facilitating ambitious
climate targets and preserving biodiversity.

12

Pull all levers to make land and food systems more sustainable: Although supply-side measures tomake agricultural production systems more resource-efficient, demand-side transitions to healthy
diets and low food waste, and systemic solutions to disincentive land system change and associated
GHG emissions are each yielding substantial progress on some Global Commons domains, none canon their own achieve - despite their ambitious design - the vision of returning within those Planetary
Boundaries that are closely tied to land use and agriculture. Thus, policy coherence is key toharnessing the many synergies between individual strategies and is likely to have many co-benefits inother areas, such as nitrogen-related air and water pollution and public health.
Beyond the physical dimensions of the Global Commons domains assessed, we also recommend tofurther take into account measures that primarily target societal development goals and that canalso have substantial impacts on the Global Commons. Many of these interventions can directly or
indirectly affect the justice, acceptability and feasibility of policies targeting the Global Commonsdomains, such as improving global justice in sharing the burden for implementing transformations,gender equality and access to education.
The feasibility of the implementation of such ambitious measures will depend on well-working
governmental institutions and strong international cooperation. Although each government should
control its own transformation strategy, coordination and compensation mechanisms at the global
level are critical given the significant challenges arising from the profound transformations in theenergy, agricultural and industrial systems, particularly in the global south. International cooperationand strong regional institutions will be needed to prevent leakages in the impact of policies,
especially in the land sector and between the Global South and Global North. Moreover, due to thenon-predictability of all impacts of certain measures, monitoring and readjustment strategies will benecessary and should be included in the conception of governance strategies aiming to keep the
impacts of human activities on the Global Commons domains within Planetary Boundaries.

131. Introduction
There are increasing signs that the Global Commons, the biophysical systems that as a whole keep
the Earth System stable and resilient and are the foundation of human development and prosperity,
are under threat. Our Earth System is to a considerable extent outside of the safe operating space forhumanity. Six of the nine Planetary Boundaries are already transgressed (Richardson et al. 2023).
Rapid, far-reaching and decisive action is needed to improve the state of the Global Commons tosuch an extent that the stability and resilience of the Earth System can be restored and maintained in
the long term.
The Global Commons Stewardship (GCS) project, initiated and led by the Center for Global Commons(CGC) at the University of Tokyo, in partnership with PIK, SDSN, WRI and SYSTEMIQ, aims at thedevelopment of a conceptual framework and strategies for Global Commons Stewardship.
The lead questions guiding this assessment report are:●●To which extent can deep transformations in the energy and the land use sector, and the
production and consumption sectors contribute to effectively safeguarding the Global Commonsdomains by keeping in or returning the Earth System into the safe operating space of thePlanetary Boundaries?
Which synergies and trade-offs between these transformations have to be taken into accountwhen designing policy strategies?

To address these questions, we used the PIK integrated assessment modelling framework (PIAM), at
the core of which is the REMIND-MAgPIE model (see Annex 1) to perform a comprehensive
assessment of how the system transformations identified in the GCS project can contribute to thestewardship of the Global Commons. We evaluated a number of scenarios describing the evolution ofindicators of the five Global Commons domains (Fig 1.1.) under different sets of assumptions,
including the implementation of three Systems Transformations (Fig1.2). The transformations
assessed here were based on the System Transformations described in the Global Commons
Stewardship Framework (GCSF 2022) developed within the CGS project. For a more detailed
description of the transformations and how they were implemented in the modelling framework,
see Annex 3.

Fig. 1.1: The five Global Commons domains (GCSF 2021)

14

Fig. 1.2: System Transformations implemented in the REMIND-MAgPIE modelling framework

Main scenarios assessed
The scenarios assessed combined projections of underlying societal development with sets ofinterventions related to the Energy Systems, the Land Use, and the Production and Consumption
transformations (Fig 1.2). Societal development was represented by the Shared socioeconomic
pathways (SSPs), mostly SSP2, the “middle of the road” projection (see Riahi et al. 2017), and, in one
case, by SSP1 - the “sustainability” pathway. The sets of interventions selected tied with the System
Transformations described in the framework paper developed in the GCS project (GCSF 2022),
although not all aspects could be implemented in REMIND-MAgPIE. To enable a more detailed,systematic analysis of the contributions of certain aspects of a Land Systems transformation to
successfully preserving the Global Commons domains, we distinguished a number ofsubtransformations in this field. The scenarios were designed in a way that they can be compared indifferent sequences to analyse the individual effects of the Interventions in different combinations.
Figure 1.3 provides an overview of the scenarios and the scenario sequences implemented, which
include:
15

●
●
●
●

●
●
●

An “National Policies Implemented (NPi)” scenario, including only policies that are currently ineffectA “Nationally Determined Contributions (NDC)” scenario, assuming the implementation of the
NDCs pledged until the time of COP26
A “All transformations” or “Global Commons Stewardship” scenario, designed to sustainably
manage all the Global Commons domains assessed by combining all transformations assessed
A “Sustainable Development” scenario, that combines all transformations with assumptions on
more sustainable GDP and population growth as described by the Shared Socieconomic Pathway
1 (Riahi et al. 2017)
Scenarios including only one of each of the System Transformations (“Energy Systems
Transformation”, “Land Systems Transformation”, “Production and Consumption Transformation”)
Scenarios with only subtransformations of the Land Systems transformation (“land-based
solutions”, “resource efficiency on land”, and “sustainable food consumption” )Several scenarios combining two or more subtransformations and/or transformations.

Fig. 1.3: Overview of the main scenarios simulated and some possible comparisons. Comparing two scenarios
linked with an arrow allows identifying the contribution of a specific intervention in a certain combination.

Indicators used for the Global Commons domains
Key indicators of the Global Commons domains, along with targets based on the Planetary
Boundaries framework were used to assess the contribution of the transformations to successfully
safeguard these domains. The outcomes of the scenario runs were compared with the effects of thetrends continued (NPi) scenario, and a set of targets for Global Commons domains key indicators,
most of them compatible with the Planetary Boundaries framework by Steffen et al. (2015). For a listof target values, see Annex 2.
An exception was made only for the indicators for the Climate System and the Cryosphere. To avoid
ongoing impact on the Climate system in the long term, GHG emissions have to remain stable, and16the net emissions of long-lived gases such as CO2 must reach zero. Thus, targets for GHG emissionsfor 2030 and 20250 were chosen as intermediate values for a trajectory that has a high probability ofkeeping global temperature change below 1.5°C with limited overshoot
Table 1.1: Description of key indicators for assessing the contribution of the Transformations to preserving the
Global Commons domains and their relationship with the Planetary Boundaries. The indicator used for directcomparisons with each Planetary Boundary is marked in bold.2
GlobalCommonsdomainKey indicatorused forassessment

Description of the indicator’s relationship with the
Global Commons domain

Related Planetary
Boundaries

GHG emissions

Acts as a proxy for climate change mitigation
ambition. Measured in GWP100 CO2 equivalentemissions. Targets for each year are chosen to beconsistent with trajectories that would lead to 1.5°C
by the end of the century with minimal overshoot.

Climate Change, Ocean
Acidification

Global Mean
Temperature(GMT) change

Indicates the human impact in both the climate
system and the cryosphere. The response of GMT tohuman activities follows complex dynamics, being
dependent on the timing and nature of emissions ofboth GHG gases and aerosols.

Climate Change

Aragonitesaturation rate

Direct proxy to ocean acidification. Under low
saturation rates, corals and other calcifying organisms
have more difficulty creating and maintaining theirshells, which affects the stability and diversity ofmarine ecosystems. Human activity affects aragonite
saturation rate mainly via CO2 emissions to theatmosphere. The CO2 gas dissolved in seawater
increases its acidity and reduces aragonite saturation
rate.

Ocean Acidification

Effective
Equivalent
Stratospheric
Chlorine (EESC)

Indicates the effective amount of ozone-depleting
substances in the atmosphere.

Ozone Layer

Forest cover

Total forest area, including both natural and managed
forests.

Land System Change

Consumptive
agricultural
water use

Consumptive freshwater use in agriculture, excluding
infiltration and runoff but including irrigation losses
through evaporation.

Freshwater Use

Human-induced
N fixation

Total Nitrogen (N) added to the landscape due tohuman activities, including inorganic N fertilisation

Nitrogen Flows2

The indicators are also represented in the GCS Index (SDSN et al. 2021). However, trade in goods is not fully
considered in a way that allows statements about spillover effects. For more information on spillover effects
between regions and policy options to tackle them, see GCS 2023. Effects of trade in primary energy sources,
although represented in REMIND-MAgPIE as well, are not listed separately. The associated emissions areallocated to the region where they are used, regardless of where the product produced thereby (e.g. steel) is
ultimately consumed.

17

and biological fixation by crops.
Biodiversity
Intactness Index

Ratio of the averaged plant and vertebrate
populations to their presumed pre-modern levels.

18

Biosphere Integrity

2. Implemented policies and current commitments
Motivation and Methods
The state of the Global Commons is currently threatened by human activity, with several Planetary
Boundaries already transgressed. Although many forms of anthropogenic pressure to the Global
Commons continue to increase, the past decades have seen some level of progress in environmental
policy that do alleviate some of this pressure. Besides, most countries have voluntarily committed toachieve climate protection goals throughout the 21st century as part of the Nationally Determined
Contributions (NDCs) of the Paris Agreement, which would have effects on other Global Commonsdomains besides the climate.
Here we evaluate scenarios that project the continuation of implemented policies or the realisationof current commitments into the future. In the Nationally Implemented Policies (NPi) scenario, it was
assumed that only currently implemented policies, including protected areas, are continued
throughout the century. Greenhouse gas (GHG) prices are assumed to grow and converge more
slowly, leading to emission trajectories in line with bottom-up studies on the effect of current
policies. In the Nationally Determined Contributions (NDC) scenario, on top of current policies all
NDC targets submitted by the UNFCCC parties by 2021 are assumed to be achieved. This includes
regional technology adoption, deforestation reduction, afforestation and general GHG reduction
targets, the latter being achieved by implementing regional prices on GHG emissions.

Key findings
If only the currently nationally implemented policies remain in place until 2050 (NPi scenario),
humanity is on track to worsen the state of most Global Commons domains and cross several
Planetary boundaries in the next century. The boundaries for Nitrogen Flow, Land-System Change andBiosphere Integrity have already been crossed today, and no further action envisaged under the NPi’s
would move these indicators substantially away from their boundaries by 2050. With just the controls
currently in place on emissions of CO2 and other greenhouse gases, the Planetary Boundaries for
Climate Change and Ocean Acidification would also be crossed by 2050.3 Although the sustainable
limits for global total agricultural water use would not be crossed by then, current trends would also
increase water consumption towards unsustainable levels in many regions of the world. The only
indicator that is set to improve is the one for the Ozone Layer, with the successful implementation of
the Montreal Protocol bringing ozone depletion back inside the Planetary Boundary.
A complete worldwide implementation of the Nationally Determined Contributions (NDC scenario)
on emissions reduction, land protection and afforestation would lead to substantial progress backtowards the Planetary boundaries for Climate Change, Ocean Acidification and Land systems Change,
but not enough to remain inside the boundaries or even stop degradation at current (2015) values.
Furthermore, the pressures of increased land scarcity and a possible reliance on bioenergy for3

As described in Section 2.3, we define the Planetary Boundary as 1.5°C warming over the preindustrial value,
the target set by the Paris Agreement. As current warming is around 1.1°C, the target has not been crossed yet,but would be in 2050 if current policies continue. In this point we deviate from the Planetary Boundaries
framework (Steffen et al. 2015) which defines Climate Change as an atmospheric CO2 concentration of 350
ppm. Based on this indicator and value, the Planetary boundary for Climate has already been crossed, and evenall the transformations investigated here cannot bring CO2 concentrations back below that value.

19

reducing emissions would lead agriculture to somewhat worsen the state of the Nitrogen Flow andFreshwater Use indicators.

Effects of implemented policies (NPi) and current commitments (NDC) scenarios on the
Global Commons domains
Effects on the Climate: If just the current nationally implemented policies (NPi) are kept in place,climate change will advance significantly, with 1.95°C warming above preindustrial levels in 2050,
already surpassing the 1.5°C target in 2035. This is caused by GHG emissions increasing to 64Gt
CO2eq/yr by 2050. Compared to the NPi scenario, the NDC contributions as agreed at the COP26 in
Glasgow could reduce GHG emissions by 22 Gt CO2eq/yr, just around 40% of the reduction required
to stay on track for the 1.5°C target. We assume the target trajectory of GHG emissions to be that ofour all-transformations scenario (11 Gt CO2eq/yr in 2050), in which warming is kept under 1.5°C withlimited overshoot.
Consequently, the NDCs would prevent just 0.13°C of warming by 2050, with global mean
temperatures still rising by 1.8°C in 2050. Crucially, since net zero CO2 emissions are not reached
before 2100 in the NDC scenario, temperatures continue to steadily rise into the next century.
Effects on Ocean Acidification: The continued CO2 emissions under the NPi scenario lead to a
substantial worsening of ocean acidification by 2050, with aragonite saturation rate dipping to well
below 2.8, a level considered minimum to safeguard marine ecosystems. Reductions in emissions dueto the NDCs improve these conditions, but increase aragonite saturation just halfway towards thetarget level.

20

Fig. 2.1: Effects of existing commitments (NDCs) on the Global Commons domains indicators. The grey
rectangles show the evolution of the indicators between 2015 and 2050 in the scenario with only the NationallyImplemented Policies (NPi) for comparison, while the red rectangles show the effect of the NDCs relative to theNPis in 2050. Dashed lines represent the defined 2050 targets for each indicator.

Effects on the Ozone Layer: The nationally implemented policies scenario includes full compliancewith the Montreal Protocol, which effectively regulates emissions of ozone depleting substances.
Those policies are also included in all other scenarios. Therefore, ozone depletion potential (asmeasured by EESC) returns to safe pre-1980 levels before 2050 in all scenarios.
Effects on the Land Biosphere: The effects of the NDCs on the land biosphere are the result ofcomplex interactions between the pledges on emissions reductions and those on land conservation,
and afforestation. Mostly due to large afforestation pledges, especially from China, the NDCs
substantially increase forest cover by 131 Mha in 2050. Still, the NDCs fall short of reaching the 4300
Mha target by almost 300 Mha.
However, in order to reach the emissions reduction NDC pledges, the energy system demands highamounts of bioenergy, especially from biofuels, to decarbonize the transport sector. This createspressures in the agricultural system and leads to an expansion of irrigated agriculture, increasing
agricultural consumptive water use by 132 km3/year, and to higher nitrogen use. The effects from thedifferent kinds of pledges on land use, involving an increase in both cropland and managed forests,
counteract each other regarding the aggregate impacts on biodiversity, leading to little to no effecton the Biodiversity Intactness Index (BII).

21

3. Transforming Energy Systems
Motivation and Methods
Human energy systems exert immense pressure on the Global Commons. Besides generating the
majority of carbon dioxide emissions, which threaten both the climate system and the oceans
through acidification, they also cause widespread air pollution. The use of bioenergy as areplacement for fossil fuel sources is a promising cheap option for reducing GHG emissions, andtechnologies such as Bioenergy with Carbon Capture and Storage (BECCS) can even lead to the net
removal of carbon dioxide from theatmosphere. However, producing cheapbiomass at the scale demanded by ambitious
climate targets leads to massive pressure onland systems.
Here we evaluate the outcomes of an Energy
Systems Transformation (Tene) on indicators of
the five Global Commons domains. The Energy
Systems transformation includes policies andassumptions throughout human energy
systems,
includingcarbonpricing,
electrification and pushes for certain
technologies (Fig 3.1).
In the Energy Systems Transformation, a priceis set on all GHG emissions, except for those Fig. 3.1: Main interventions included in the Energy
from the land use sector. Non-CO2 emissions Systems Transformation (Tene).
are priced according to their GWP100 CO2equivalent. Prices increase over time, and are set at a level that, if applied together with all otherinterventions, keeps global mean temperature change under 1.5° C with 66% probability with limited
overshoot. GHG prices start at lower levels in developing countries, converge to a single global priceof 92 USD per tonne of CO2eq in 2050 and continue rising steadily after that (see Chapter 6).
For the transport sector, the Energy Systems Transformation includes a strong push for electrification,
and a general push for public transit: Almost all light driving vehicles are assumed to be battery
electric by 2050, as well as most trucks. Personal mobility demands in wealthy regions converge tosustainable levels and are more reliant on public transit and non-motorized modes. Intercity travel
routes are served by high-speed electric rail wherever it is feasible. We also assume a reduction in
overall freight transportation demand due to the phase-out of fossil fuels, which make up for a largepart of long-distance shipping demands today. Light vehicles and most trucks are assumed to bebattery electric by 2050. Moreover, options are included for Carbon Capture and Use (CCU)
technologies, which, coupled with hydrogen production, can help provide lower emission fuels for
harder to decarbonize sectors such as aviation and long-haul transport.
For the buildings sector, the Energy Systems Transformation assumes a strong push for electrification,induced by lowered costs for heat pumps (i.e. substantial subsidy to foster heat pump adoption forclimate control).
22

Finally, Direct Air Capture (DAC) technologies are made available to abate leftover emissions, alongwith other Carbon Dioxide Removal (CDR) technologies. Adoption of these and many of thetechnologies in the transport and buildings sector depends on their relative prices and the inclusionof a price on GHG emissions.

Key findings
The Energy Systems Transformation has strong effects on safeguarding the Climate, Cryosphere andOceans, but can have detrimental effects on the Land Biosphere Global Commons domains.
Transforming the energy systems towards sustainable energy sources and shifting towards moresustainable transport modes would reduce GHG emissions by 39 Gt CO2eq/year in 2050, a 60%
reduction relative to a scenario with only the currently implemented policies. This would prevent
around 0.19°C of warming. Most of the avoided emissions would be of CO2, keeping Ocean
Acidification at relatively safe levels inside the Planetary Boundary throughout the century. However,an increased reliance on bioenergy ultimately has detrimental effects on the Land Biosphere, leading
to higher deforestation rates, use of nitrogen fertilizers, agricultural water consumption anddegradation of biodiversity.
The GHG price levels implemented in the energy sector are relatively modest, reaching around 90
U.S. dollars per ton of CO2eq in 2050, being enough to limit warming to 1.5°C by 2100 (with limited
overshoot) only in combination with all other transformations. However, it is already enough to cause
substantial transformations in the energy system. Electrification of final energy uses anddecarbonization of the electricity supply arises as the most cost-effective strategy in most cases
where it’s technically feasible. The share of electricity in the global final energy supply increases fromcurrently below 20% to ~25% in 2030, to 45% in 2050. A combination of reduction in the cost of
renewables and carbon pricing leads to an almost complete phase out of coal and oil use in electricity
generation, and reliance on gas falls below 2% of the electricity supply in 2050.

Effects of the Energy Systems Transformation on the Global Commons domains

23

Fig. 3.2: Effects of the Energy Systems Transformation (Tene) on the Global Commons domains indicators. The
grey rectangles show the evolution of the indicators between 2015 and 2050 in the scenario with only the
Nationally Implemented Policies (NPi) for comparison, while the yellow rectangles show the effect of thetransformation relative to the NPis in 2050. Dashed lines represent the defined 2050 targets for each indicator.

The interventions included in the Energy Systems Transformation (Tene) have a strong positive impact
in safeguarding the Climate, the Cryosphere and the Oceans. By 2050 GHG emissions are reduced by
39 Gt CO2eq/yr from 65 to 26 Gt CO2eq/yr. This is ~70% of the reduction required to reach the
1.5°C-compatible levels of the all-transformations scenario (11 Gt CO2eq/yr). The reductions in GHG
emissions lead to the avoidance of 0.19°C warming in 2050, and almost 0.5°C by 2100 (fig. 3.2).
Furthermore, the Energy Systems Transformation is the only transformation that allows achieving CO2
neutrality in this century (although only by 2100), leading to a stabilisation of warming at around 2°C
after then.
The GHG reductions are achieved mainly due to the introduction of a moderate price on GHG
emissions in the energy, industry and transport sectors, but is also linked to the reduction in overall
energy demand with the pushes for sustainable options in transport and buildings heating.
Introducing Carbon Capture and Utilization (CCU) technologies plays a relatively minor role in thetransformation, reusing less than 0.5 Gt CO2eq/yr in 2050 and roughly doubling by 2100. Carbon
Dioxide Removal (CDR) technologies do play a somewhat larger role in offsetting residual emissions(respectively 2.5 and 7.5 Gt CO2eq/yr in 2050 and 2100). However, Direct Air Capture (DAC)
technologies are not competitive at the moderate GHG prices of the Energy Systems Transformation,with Bioenergy with Carbon Capture and Storage (BECCS) being the dominant CDR technology in this
scenario.
24The reductions in GHG emissions lead to the avoidance of 0.19°C warming in 2050, and almost 0.5°C
by 2100 (Figure 3.3). The Energy Systems Transformation can achieve CO2 neutrality in 2100, being
the only intervention analysed to achieve it in this century and leading to the stabilisation of warming
around 2°C after then. The strong reductions in CO2 emissions induced by the Energy Systems
Transformation also make it necessary to successfully steward the Oceans, as only scenarios that
include it prevent Ocean Acidification from crossing the Planetary Boundary, even in the scenario
with only the Energy Systems Transformation, with global aragonite saturation rate remaining above
2.8 throughout the century.
On the other hand, the implementation of GHG pricing exclusively in the energy sector leads to aheavy reliance on bioenergy for its decarbonization, creating pressure on the land biosphere in theabsence of specific policies to safeguard it or prevent the reliance on bioenergy. Deforestation
increases slightly on top of the already high levels of the NPi scenario, leading to the loss of anadditional 2.6 Mha of forest by 2050. This pressure not only on forests but also on other naturalenvironments leads to some additional biodiversity loss, although the effect is much weaker thanthat of current trends (NPi) between 2015 and 2050.
Even though our scenarios assume that 2nd generation bioenergy crops themselves should not be
irrigated, the additional pressure on land pushes an increase in irrigation of other crops. Water
withdrawals for irrigation also increase due to a higher availability of water during the growing periodof cultivated crops in this scenario. This happens as a consequence of mitigation efforts in the energy
system, which involves changes in intensity and patterns of climate change impacts that affectagriculture, such as crop yields and accessible freshwater resources for irrigation. Resulting expansionof irrigated agriculture causes consumptive agricultural water use to increase dramatically, which
pushes global agricultural water use close to crossing the Planetary Boundary, being the onlyboundary not crossed in the NPi scenario by 2050. Even though the Planetary Boundary is notcrossed, at regional scales this effect can be very significant, making an additional 35 Mha of irrigatedarea suffer by having water needs above their local environmental flow requirements. The overallpressure on agricultural systems also increases nitrogen fixation.

25

Fig. 3.3: XXI century trajectories of median estimates of Global Mean Temperature change relative to thepreindustrial period (top left), Aragonite saturation rate (top right) and net GHG (bottom left) and CO2 (bottom
right) emissions for the scenarios with only the currently implemented policies (NPi), only the NDCs (NDC), only
the individual transformations (Tene, Tland, Tpc) and with all transformations combined (Tall). The horizontal
black line shows target values for reference.

26

4. Transforming the industry sector
Motivation and Methods
The global industry has been the fastest-growing sector in terms of greenhouse gas emissions in thelast 20 years, accounting for 14 or 20 GtCO2 (without and with indirect emissions, respectively) in2019 (Bashmakov et al. 2022). In addition to being a major emitter of greenhouse gases, the global
industry puts pressure on other planetary boundaries. Of particular interest is the boundary for the
introduction of novel entities. Recent research suggests that this boundary is also already exceeded(Persson et al. 2022).
The decarbonization of the industry sector is expected to be particularly challenging as relevant
technologies are still to be developed or deployed to a significant scale. Moreover, significant
uncertainty remains about the main technologies that will drive the transformation of the industry
sector. Significant efforts are necessary to avoid that the industry becomes a bottleneck in the global
transition towards a sustainable economy which supports/allows for keeping the Global Commonsdomains in the safe operating space of the Planetary Boundaries.
Here we compare a scenario with only the current Nationally Implemented Policies (NPi) with ascenario that additionally includes a Sustainable Production and Consumption Transformation (Tpc).
This transformation assumes radical changes in the use and production of material goods which leadto substantial increase in material efficiency. For the consumption side, more sustainableconsumption patterns lead to longer and more communal use of consumer goods (which is enabledby products with longer durability and repairability (sharing and circular economy). Examples are an
increased use of car-sharing services, preferred buying of second-hand items or extended use of
single items. The total amount of materials required to provide a specific service (or use) is lower. On
the production side, we assume a more efficient use of materials in the production of goods.
Examples are products manufactured with less materials or more durable products, whose longer
lifetime would allow for the same service or use to be provided using less materials.
These assumptions are implemented in
REMIND-MAgPIE as reductions in the
demand for materials in the industry sector.
Based on bottom-up estimates of the effectsof these assumptions (Grübler et al. 2018),
we implement substantial reductions indemand for the steel (76%), cement (20%)
and chemicals (32%) sectors in the absenceof other interventions for the Sustainable
Production
andConsumption
Transformation. These reductions are Fig. 4.1: Interventions included in the Sustainable
phased-in from 2020 to 2050. With less Production and Consumption Transformation.
material production, the demand for energy
in these sectors is also reduced. It’s important to note that industrial production can also be further
reduced in response to other interventions, especially those that change energy prices for the sector.
We further evaluated scenarios examining the potential independent and combined contributions ofspecific interventions on the industry subsector for reducing CO2 emissions and plastic waste27

disposal. Those include carbon pricing at 1.5°C compatible levels (see Chapter 3: Transforming Energy
Systems), the same reduction in demand for materials as in the Sustainable Production andConsumption, here called Low Material Demand (LMD), the use of carbon capture and storage (CCS)
technologies, and an additional push for deeper adoption of hydrogen (H2 push).
We also evaluate scenarios that compare how plastic flows to the environment change in response toa circular economy strategy for the plastics sector. The plastics sector is fossil-based and often
produces short-lived products that have detrimental effects on the environment at their end of life.
These scenarios further implement a push for circularity where high recycling rates are achieved
rapidly at a global scale, besides an acceleration of the transition from primary to secondary steel
production.

Fig. 4.2: General setup of the industry-specific scenarios. A set of individual industry-specific transformations
are assessed on top of the reference scenario, as well as a scenario including all interventions. The effect of
circular approaches for waste management is tested in an ex-post analysis.

Key findings
The Sustainable Production and Consumption Transformation has relatively small effects on
safeguarding the Climate, Cryosphere and Oceans. The improvements in material efficiency and moresustainable consumption habits ultimately lead to lower industrial production and energy demand,
which reduces GHG emissions by 16 Gt CO2eq/yr relative to current policies in 2050. These
reductions can prevent 0.09°C of warming overshoot in 2050 and also have benefits for Ocean
Acidification.
Results of the industry-specific pathway modelling show that carbon pricing is essential but
implementing industry-specific policies will enable a faster and deeper de-carbonization of the sector.
Results suggest that circular economy approaches have the potential to mitigate plastic pollution
without compromising climate goals.
De-materialization of the economy offers significant reductions of the pressure that the global
industry puts on global commons. However, its feasibility remains uncertain, which is why robust
policy for the transformation of the global industry should not rely strongly on a deep
de-materialization of the economy. Carbon capture and storage is critical for deep decarbonization of
the global industry as process emissions cannot be mitigated by means of low-carbon energy carriers.
28

At the same time, deploying carbon capture is not a licence to continue to use fossil fuels. The
adoption of hydrogen-driven technologies in the industry should concentrate on the specificapplications where this technology is critical for deep decarbonization.
Finally, circular approaches for plastic waste mitigation could help mitigate the introduction of novel
entities in the earth system while avoiding putting further pressure on the climate and the energy
transition. However, further research is required that defines the technical, economic, andenvironmental limits of this alternative, including the potential release of microplastics and otherspecies in recycling processes.

Effects of the Sustainable Production and Consumption Transformation on the Global
Commons domains
The Sustainable Production and Consumption Transformation helps safeguard the Climate andOceans relative to the current policies (NPi) scenario. In the absence of other policies, the reduced
industrial production leads to a strong reduction of industry’s GHG emissions. These reductions comenot only from the emissions associated with industrial processes and fuel burning in the industry
itself, but also from the reduction in energy demand, especially electricity, which in turn reduces
emissions from the energy supply.
In total, the Sustainable Production and Consumption Transformation alone reduces GHG emissions
by 16 Gt Gt CO2eq/yr in 2050, which is close to the amount achieved by the NDC commitments
currently in place. This leads to an avoided 0.09°C of warming. Since a large share of the avoided
emissions are of CO2, Ocean Acidification also improves significantly, but not enough to movearagonite saturation back into the safe space of the Planetary Boundary if only this transformation isaffected.
The reduction of industrial material has very small effects on the indicators related to the Land
Biosphere. Effects relative to the NPi scenario, are mostly due to small relocations of agricultural
production. Although it would be expected that the lower industrial activity would require lessenergy, and therefore less bioenergy, if current policies are followed bioenergy plays a very small roleon energy systems worldwide. Therefore, the reduction in energy demand from more sustainableproduction and consumption patterns has but a weak link to the land systems. However, that canchange if the energy systems are also transformed toward having a higher reliance on bioenergy, as
can be seen in the next sections.

29Fig. 4.2: Effects of the Sustainable Production and Consumption Transformation (Tpc, blue) on the Global
Commons domains indicators. The grey rectangles show the evolution of the indicators between 2015 and2050 in the scenario with only the Nationally Implemented Policies (NPi) for comparison, while the blue
rectangles show the effect of the transformation relative to the NPis in 2050. Dashed lines represent thedefined 2050 targets for each indicator.

30

GHG emissions from the global industry
Under currently implemented policies, greenhouse gas emissions from the global industry are
expected to increase by 2.4 GtCO2eq/yr by 2050, reaching 14.1 GtCO2eq/yr. While carbon pricing
roughly halves GHG emissions to 6.7 GtCO2eq/yr by 2050, the proposed industry-specifictransformations enable significant further reductions, reaching 3.6 GtCO2eq/yr by 2050. This is asignificant reduction of 10.5 GtCO2eq/yr compared to NPi.
Dedicated industry-specific policies can complement carbon pricing, allowing for a deeper and fasterdecarbonization of the global industry. The push for lower material demands further reduces
emissions by 1.6 GtCO2eq/yr by 2050 on top of the reductions achieved by carbon pricing.
Introducing carbon capture and storage as an option has a similar effect, with a reduction of 1.7
GtCO2eq/yr. A stronger deployment of hydrogen-driven technologies in the industry allows for saving
0.3 GtCO2eq/yr. Deploying the full set of industry-specific interventions takes us beyond reductions
from carbon pricing with a total additional reduction of 3.1 GtCO2eq/yr by 2050.
The importance of each intervention for reducing industry emissions can be quite different across its
subsectors. Lowering the demand for materials has a substantial effect on steel, cement andchemicals emissions, following the reductions in demand of those specific materials. Carbon pricing
has a very important contribution on decarbonizing the steel sector, as electrification of secondary
steel production is much simpler than that of cement, from which a large share of emissions comefrom the processes themselves, and of chemicals, where besides process emissions, fossils are also
used as feedstocks. Setting a price on carbon emissions also creates an incentive for steel recycling,with the share of secondary steel increasing from under half to two thirds of total production with
the implementation of carbon pricing.
For similar reasons, the use of Carbon Capture and Storage technologies can be more important thanlowering material demand for reducing emissions in the cement and chemicals sectors, as it allows
capturing emissions that are not related to energy use. It is important to stress that deploying CCS
technologies does not mean that the industry can continue to use fossil fuels, as the scale-up of thisyoung technology is challenging and massive efforts are already required to be on-track to therequired capacities to capture process emissions in climate-compatible futures. This way, phasingout fossil fuels and deploying CCS for the remaining process-emissions are complementary measuresand incentives for the development and rapid scale-up of carbon capture and storage technologies
are needed to mitigate process emissions. Other alternatives to mitigate carbon emissions from thecement subsector include the development of novel chemistry for the process and the replacementof cement by other materials.

31

Figure 4.3: Effects of the industry-specific interventions on total GHG emissions of the global industry (top) andCO2 emissions of its subsectors in 2050.

Pushing for hydrogen adoption beyond the economic optimum under carbon pricing has just a small
effect on reducing industry emissions across sectors, as it is generally crowded out by electrification
where possible. The effect on emissions is small despite the hydrogen push intervention leading to a
substantial increase in hydrogen use in industry of 12 EJ/yr worldwide, which is around 8% of current32

(2020) total industry energy use, beyond the 15 EJ/yr resulting from the reference carbon
price-driven scenario.

Transformational challenges
Electricity and hydrogen use
Electrification is in most cases the most efficient and proven path for decarbonizing industry, but will
put more pressure on the transformation of power systems. The path to decarbonizing the power
sector relies on proven technologies whose scale-up has gathered considerable pace in the last
decade, such as photovoltaic solar and wind power.

Figure 4.4: Electricity use in the global industry for the proposed scenarios and interventions.

Electricity use in the industry at the global level is expected to roughly double by 2050, reaching 56.8
EJ/yr, in a future where current policies continue. Introducing carbon pricing increases electricity
demand slightly by 2.7 EJ/yr. The LMD push is the intervention that most significantly reduces thepressure that the global industry puts on the power sector, reducing electricity demand by 9.9 EJ/yr
in 2050 as compared to the reference scenario. The effect of CCS is neglectable and the H2 pushdecreases the direct use of electricity in the industry by only 2.7 EJ/yr. However, producing greenhydrogen requires large amounts of electricity, which would in turn put more pressure on the power
sector.
The electrification of some processes in the industry sector, such as the reduction of iron ore, istechnically constrained. Thus, incentives are required that foster the fast adoption of hydrogen for
33

these applications. However, subsidising the deployment of hydrogen beyond the necessary scoperisks triggering additional transformational challenges which can hinder the pace of transformationand the economic performance of the system. Although pushing for hydrogen reduces electricity use
in the industry sector itself, it disproportionately increases the demand for electricity in the energy
sector for hydrogen and synfuels production. Therefore, an excessive reliance on indirectelectrification, through hydrogen production, instead of directly electrifying processes where
possible, leads to further pressure on the transformation of the electricity sector.

Demand for bioenergy in the industry sector
Analysis of the effects of the interventions on the total demand for bioenergy in the industry sector
points to an important potential tradeoff. It underlines the results of Chapters 5 and 6, highlighting
how an intensive use of biogenic energy sources for industrial energy demand can contribute toincreasing pressure on agricultural systems and may threaten the land biosphere.

Figure 4.5: Use of bioenergy in the global industry for the proposed scenarios and interventions.

The use of bioenergy is expected to decrease by 5.9 EJ/yr to reach 5.7 EJ/yr in 2050, for the scenario
where only currently implemented national policies remain. Implementing carbon pricing asprescribed in our reference scenario is projected to increase the demand for bioenergy in theindustry sector by 14.4 EJ/yr (if no countermeasures are implemented), as there is an incentive inplace to use low-carbon energy carriers.

34

Residual fossil fuels use (carbon lock-ins)
Figure 4.6 shows the residual use of fossil fuels in the global industry sector for selected years. We
observe that in the short term, until 2030, carbon pricing in the reference scenario allows for alimited reduction in the use of fossil sources. The LMD intervention achieves further reductions
already by 2030. By 2050, carbon pricing is able to phase out a major share of fossil sources. The
reference scenario with carbon pricing is the most effective in phasing out the use of solid fossil
energy sources. Again, the only sector-specific intervention delivering a significantly deeper
de-fossilization is the transition to lower material demands in the economy. When all sector-specificinterventions are deployed, the use of liquid fossil fuels in the industry is reduced. In the long term,
all mitigation scenarios manage to phase out most fossil sources.
The scenario where CCS has deployed exhibits a slightly higher amount of fossil sources in the longterm, whose corresponding emissions could be captured and stored. However, the amount is very
low and it is clear that phasing out fossils is part of all mitigation strategies. With this, CCS is relevant
for the transformation of the global industry to mitigate process emissions, not emissions from fossil
sources.

Figure 4.6: Residual use of fossil fuels in the global industry by type of fuel.

35

Circularity push
In the following, we present the results of the ex-post analysis of the effects of a stronger
deployment of circular strategies for plastic waste mitigation. We compare the effects of a circular
future against those of a reference scenario based on SSP2-type socio-economic developments. First,
we present our projections for plastics production in the next decades, for three selected scenarios.
Second, we analyze the fate of plastics for these two scenarios in terms of carbon flows. Later, we
present our estimation of variables relevant to the protection of global commons domains. In
particular, we analyze plastic waste introduction into the environment and the emission ofgreenhouse gases.

Figure 4.7: Evolution of plastic waste production under different scenarios.

Before analysing the effect of circularity strategies, it is necessary to understand the effect thatdifferent policies have on the production of plastics and plastic waste in our models. Figure 4.7 shows
the total projected production of plastic waste until 2050 for the scenarios selected for the circularity
analysis: NPi, reference (with carbon pricing), and the full set of transformations (alltransformations). We observe a strong reaction of the production system to carbon pricing, with acomplete deviation from the NPi trend. While under currently implemented national climate policies(NPi) our models project a nearly production of plastic waste of 539 Mt/yr by 2050, this figure goes
down to 316 million tons when the assumed carbon price trajectory is implemented. These
projections are comparatively low, with other sources estimating future production at 1 Gt of plastics
per year by 2050, for a middle-of-the-road-like development scenario (SSP2)4. This could lead to4

Stegmann, P., Daioglou, V., Londo, M., van Vuuren, D. P. & Junginger, M. Plastic futures and their CO2
emissions. Nature 612, 272–276 (2022).

36

underestimating impacts and should therefore be carefully analysed in future assessments. Under
the full-transformation scenario, plastic waste generation is further reduced to a significant extent, all
the way down to 176 Mt/yr by 2050. This is due mostly to the deployment of de-materialization in
the chemicals sector, under our LMD transformation.

Figure 4.8: End-of-life fate of plastic waste under different scenarios including circular economy strategies.

Figure 4.9: Emissions from plastic waste incineration for different policy scenarios and plastic waste mitigation
strategies.

Figure 4.8 compares different futures for managing the end-of-life of plastics products, for an
SSP2-like future, it compares a linear and a circular approach (solid and dotted curves) with the37

previously described transformation on top (marked with different colors). Figure 4.9 offers a closer
look at the resulting direct emissions from plastics incineration. While in the reference case, following
an SSP2-like future, plastic pollution mitigation is achieved via incineration, in the circular economy
scenario, the shares of plastic recycling increase in the next 25 years.

38

5. Transforming Land Systems
Motivation and Methods
Humanity has appropriated most of the world’s land area for its use. The impacts of humanalterations on natural land and the use of land for agriculture or infrastructure are among the oldest
and most significant human drivers of degradation of the Global Commons. Conversion anddegradation of natural land is a constant threat to biodiversity and are an important source of carbon
dioxide emissions. Intensive and extensive agricultural practices, besides displacing natural land,
affect water and nutrient cycles and release air pollutants and multiple greenhouse gases into theatmosphere. The scale and complexity of human land use systems, and the multiple Global Commons
Domains they can impact, makes interventions on them particularly prone to tradeoffs.
Here we examine the effects of a Land Systems
Transformation (Tland) on the Global Commons
Domains, as well as interactions between
different subsets of its interventions. Tland is amodel interpretation of the “Sustainable Food,
Land, Water and Oceans'' transformation in the
GCS framework. We assume radical but gradualchanges in food consumption patterns,
including a reduction in per-capita food waste
and a global shift towards healthier and moreenvironmentally friendly diets by 2050. The
dietary transition involves partial shifts fromanimal source foods to plant-based based
products, a decreasing share of processed foods
and an increasing share of healthy foods such as
vegetables, fruits and nuts, as proposed by the
EAT-Lancet Commission. In addition, daily
per-capita calorie intake of different population
sub-groups (differentiated by age and sex) Fig 5.1: Interventions included in the Land Systems
converges to levels consistent with a healthy Transformationbody weight, thus implying substantial
improvements regarding the prevalence of underweight and breaking with current trends ofincreasing prevalence of overweight and obesity (Bodirsky et al. 2020).
On the supply side, it is assumed that the sustainability of food production improves on several
fronts. Policies decreasing the amount of land available for agricultural production safeguard natureand the climate, while simultaneously spurring investment into agricultural research anddevelopment. This endogenous technological innovation facilitates higher crop yields without
sacrificing the Global Commons. Crop yields endogenously increase as a result of nature and climate
protection policies that decrease the availability of land for agriculture - described below - andincentivize investments into agricultural research and development. Livestock productivity and feed
efficiencies of several animal food systems also strongly improve, which reduces biomass and land
requirements. Efficient nitrogen fertilisation of crops and improved manure management reduce39pollution from excess nutrients in terrestrial and aquatic ecosystems as well as non-CO2 GHG
emissions. Irrigation efficiency is improved and the basic environmental flow requirements of aquatic
ecosystems are protected. Second generation bioenergy crops are only produced in rainfed
production systems to avoid trade-offs between climate protection and sustainable water use.
Several policies for the protection and restoration of natural ecosystems are included. Damage
caused by shifting cultivation to natural forests will be prevented from 2030 onwards. Naturallandscapes within areas classified by Conservation International (CI) as biodiversity hotspots(Mittermeier et al. 2004) are protected from conversion, besides all intact forest landscapes andcurrently protected areas. In total, around 30% of the global land environment is protected by 2030,
in line with the commitments in the Kunming-Montreal Global Biodiversity Framework. A GHG
pricing scheme on land use sources is also implemented. This has the effect of disincentivizing
conversion of natural land and the degradation of peatlands, as well as fostering afforestation as aland-based mitigation measure. The inclusion of agricultural non-CO2 emissions into the GHG pricing
scheme economically incentivises technical abatement of N2O and CH4 emissions.
To enable a more detailed, systematic analysis of the contributions of certain interventions topreserving the different Global Commons domains, we distinguish the following subtransformations
which comprise the Land Systems Transformation (Tland):Land-related Nationally Determined Contributions (LNDndc)
This subtransformation only includes compliance with the Nationally Determined Contributions
related to the land use sector, achieving targets for land protection and afforestation.
Sustainable food demand (LNDfood)
The LNDfood subtransformation includes interventions assigned to the assumptions that level andcomposition of food demand changes due to food waste reductions and a shift to healthy and moresustainable diets. These diets are characterised by a low share of processed and animal-source foods,
and by a total food energy intake that is consistent with a healthy body weight. This is implemented
by assuming developments towards full convergence to the EAT-Lancet diet and to a BMI considered
as healthy in all sex and age groups in 2050. Reductions in food waste are implemented by halving
the currently observed levels of food waste in High Income Countries (HIC) by 2050.
Resource-efficient production systems (LNDreseff)
For the interventions covered by LNDreseff it is assumed that agricultural production shifts to moreresource efficient and less polluting systems and management practices, thereby reducing pressureson land and water resources, decreasing nitrogen-related environmental degradation and mitigating
agricultural non-CO2 emissions. Implementation in our models include more intensive livestock
production systems, more efficient animal waste management systems, improved nitrogen use
efficiency, pricing of agricultural non-CO2 emissions, a phase-out of first-generation bioenergy crops,
protection of environmental flow requirements, and higher irrigation efficiencies.
Land-based solutions (LNDlbs)
The land-based solutions subtransformation is targeted at the dual challenge of mitigating climatechange as well as biodiversity loss. It includes the protection of forested and non-forested ecosystems
40

(including peatlands) by both price-based measures and regulatory land protection schemes.
Moreover, rewetting of drained peatlands as well as afforestation with native species are included asland-based mitigation options.
This is implemented by pricing of CO2 emissions from conversion of natural land and of GHG
emissions from degraded peatlands, protection of biodiversity hotspots, a carbon-price incentivized
afforestation using native species (restricted to the tropics due to albedo effects and confined to a
global maximum), and prevention of damage from shifting agriculture to natural forests.
All these measures decrease land availability, which is compensated by investments into research anddevelopment to increase food production while preventing land expansion.

Key findings
The Land Systems Transformation is fundamental for preserving the Land Biosphere, but also has
substantial positive impacts on the other Global Commons domains. By 2050, it would halt the loss ofnatural forest, reduce agricultural water consumption and improve human-induced nitrogen fixation
and biodiversity intactness to conditions superior to those of today. This would bring Land System
Change, Nitrogen Flow and Biosphere Integrity back within their Planetary Boundaries. These effects
are more than enough to counteract negative effects from the Energy Systems transformation inthese Global Commons domains. The combination of land interventions would also reduce GHG
emissions by 19 Gt CO2eq/year. Methane emissions would be particularly reduced, preventing 0.18°C
of warming in the medium term (2050) and minimising overshoot of the 1.5°C Paris Agreementtarget. The avoided CO2 emissions would have positive impacts on Ocean Acidification, but notenough to prevent it from degrading to levels outside the Planetary Boundary.
Individual components of the Land Systems Transformation focusing on resource-efficient
production, reduction of GHG emissions, and dietary changes, differ in terms of their individual
impact on safeguarding the Global Commons domains, and exhibit synergies and tradeoffs between
them and with other transformations.
Transitioning to resource-efficient production systems is a key supply-side intervention to reduce
human-induced nitrogen fixation and agricultural water use. However, reducing water consumption
by limiting irrigation can increase pressures on Land System Change and Biosphere Integrity, as
replacing irrigated systems with relatively lower-yielding rainfed ones requires more land area.
Pricing GHG emissions from land use change can prevent leakage effects from other interventions,
including those that can occur if regulation-based land protection or afforestation schemes likecurrent NDCs miss sufficient coverage in terms of regional distribution and types of included
ecosystem.
Each of these land protection measures are of paramount importance if interventions in othersectors further increase biomass demand, e.g. for energy use. On the other hand, land-based
solutions alone can push unsustainable intensification practices and can create tradeoffs with wateruse.
In contrast, transforming food demand towards more sustainable diets and reducing food waste
leads to strong beneficial impacts across most Global Commons domains. It can combine
synergistically with other land interventions, leading to more than additive outcomes in Land Systems
41

Change and Biosphere Integrity, as reduced demand for food frees more land to be used for
mitigation and conservation. Its beneficial effect on reducing emissions and the use of nitrogen andwater are slightly diminished when evaluated in conjunction with the other land interventions, which
ultimately make the food system more environmentally efficient and therefore reduces the burden of
additional food demand. However, it still positively affects economic variables such as food andbioenergy prices, which are mostly negatively influenced by the other land interventions. It is also key
to facilitating a multi-dimensional transformation to sustainability that also addresses humanwell-being and development.

Effects of the Land Systems Transformation and its components on the Global Commonsdomains
The Land Systems Transformation (Tland) implementation combines all four land-based
subtransformations, which encompass the inclusion of a price on GHG emissions, efficiency
improvements, dietary shift, food waste reduction and meeting the NDCs for land emissions, inaddition to other land-based mitigation solutions. As such, it emerges to be by far the most effective
transformation for safeguarding the Land Biosphere, but also has important effects on the Climate
and the Oceans.

Fig 5.2: Effects of the Land Systems Transformation (Tland, dark green) and its subtransformations (light green)on the Global Commons domains indicators. The grey rectangles show the evolution of the indicators between
2015 and 2050 in the scenario with only the Nationally Implemented Policies (NPi) for comparison, while theblue rectangles show the effect of the transformation relative to the NPis in 2050. Dashed lines represent thedefined 2050 targets for each indicator. Subtransformations are labelled as follows LNDndc: Current

42

deforestation and afforestation commitments; LNDlbs: Land-based solutions intervention; LNDfood:Sustainable food demand; LNDresff: Resource-efficient production systems

Relative to the NPi scenario in 2050, the Land Systems Transformation reduces greenhouse gas
emissions by 19 Gt CO2eq/yr, which is 37% of the gap to the 2050 emissions target, and around halfof the emissions reduction achieved by the energy transformation. This leads to a reduction in global
mean temperature (GMT) by 0.18°C, which is a similar amount to the 0.19°C reduction achievablewith the Energy Systems Transformation. The Land Systems Transformation had a particularly
pronounced effect on 2050 temperature due to the strong reductions in emissions of non-CO2 gaseswith high radiative forcing (e.g. CH4, N2O), thus making it especially important for reducing peakwarming.
The implementation of the Land Systems Transformation also leads to an increase in aragonite
saturation rate by 0.06, although this contribution was relatively small due to the more moderate
reductions in CO2 emissions compared to those of the other transformations.
As expected, the Land Systems Transformation has an important effect on safeguarding the land
biosphere indicators. Globally, it increases forest cover by 450 Mha and reduces consumptive
agricultural water use by 442 km3/yr in 2050. Moreover, it decreases nitrogen fixation by 116 Mt
N/yr, being the only transformation that can bring this indicator into the safe space below the 90 Mt
N/yr Planetary boundary. Finally, it increases the Biodiversity Intactness Index (BII) by 0.013,
suggesting that this transformation is critical to reaching the 80% intactness target.
The decomposition of the Land Systems Transformation into individual subtransformations showsthat for many indicators the overall transformation demonstrates a less-than-additive effect (e.g.
GHG emissions and global mean temperature). These diminishing returns suggest that thesubtransformations have overlapping effects. However, several indicators appear to be synergistic,
such as the increase in forest area and ensuing increases in biodiversity intactness. This likely
emerges as reductions in the consumption of red meat from the Sustainable Food Demand (LNDfood)
subtransformation facilitates the conversion of cropland to forests, which however is only
incentivized with the CO2 pricing introduced by the Land Based Solutions intervention (LNDlbs).

Land-related Nationally Determined Contributions (LNDndc)
The implementation of only the land-based NDC commitments leads to significant positive impacts
on the Global Commons domains Climate, Oceans, and the Land Biosphere. In particular, it leads to a
9 Gt CO2eq/yr reduction in greenhouse gas emissions in 2050, which is approximately half that
achieved by the full Land Systems Transformation. This reduction in emissions causes a reduction in
GMT by 0.04°C, which is around 20% of that achieved by the full Land Systems Transformation and its
CO2 component leads to an increase in aragonite saturation All the land protection and afforestationcommitments increase forest cover by 125 Mha, with an ensuing slight increase in BII of 0.001.
Importantly, implementation of the land-based NDC commitments had negligible impacts on both
agricultural water use and human-induced nitrogen fixation. These indicators were likely unaffected
because the transformation lacks any changes in demand patterns or technologies reducing
environmental impacts of agriculture. Without these drivers, while significantly more forest is sparedfrom land conversion, conversion will still occur in some regions and existing croplands and pastures
are intensified in order to meet food demand.
43

Land-based solutions (LNDlbs)
The land-based solutions subtransformation had significant impacts on the assessed Climate, Oceans,Land Biosphere Global Commons domains indicators in 2050. It includes land protection schemes
and the extension of GHG to land carbon. The intervention reduces greenhouse gas emissions by 11
Gt CO2eq/yr, a little over a half of the full Land Systems Transformation and more than the land-based
NDCs subtransformation. Additionally, the subtransformation reduces Global Mean Temperature by
0.07°C, i.e., almost double the effect of the land-based NDCs alone. The intervention had the largest
contribution to increasing aragonite saturation, with an increase of 0.05 due to the proportionallylarge reduction in CO2 emissions versus non- CO2 emissions. Forest cover increases by 110 Mha,making this the most important intervention after the land-based NDCs in increasing forest cover.
Furthermore, LNDlbs increased BII by 0.004, representing the strongest single positive effect.
However, this subtransformation can also have negative side effects. As the intervention lacks
mechanisms to reduce demand or increase production efficiency, we observed increases in
consumptive agricultural water use by 126 km3/yr as well as a slight increase in nitrogen fixation of
1.9 Mt N/yr. As land protection measures decrease the availability of productive land, intensificationis required to meet food demand where agriculture is still possible. While land-based solutions
demonstrate large potential to reduce greenhouse gas emissions and improve environmental
indicators, they will also necessitate complementary measures to reduce potentially strong, negativeside-effects.

Resource-efficient production systems (LNDreseff)
The resource efficiency subtransformation (LNDreseff) includes improvements in N and water
efficiency, livestock intensification, improvements to animal waste management, a price on non-GHG
emissions in the land sector, and the protection of environmental flow requirements, notably without
any exogenous agricultural yield improvements. The scenario led to significant reductions in GHG
emissions (11Gt CO2eq/yr), which is a little over half the reduction achieved by the full landtransformation, and increased aragonite saturation rate. It also reduces GMT by 0.09°C, which is
proportionally higher than other interventions due to the strong reduction in short-lived, high-forcing
non-CO2 emissions. The subtransformation also reduces consumptive agricultural water use by 148
km3/yr. As agricultural water availability is highly spatially variable, this decrease in consumption will
likely reduce regional violations of this important boundary. However, it slightly reduces forest cover(by 7.6 Mha), as agricultural expansion is required to meet food demand while preventing violationsof regional water availability. The scenario very slightly decreases BII, in line with the forest losses.
Lastly, efficiency gains strongly reduce N fixation by 77 Mt N/yr.

Sustainable food demand (LNDfood)
The sustainable food demand subtransformation is defined as a global convergence to the EAT-Lancet
Diet and strong reduction of food waste. Among the different interventions in the Land Systems
Transformation, it represents the most substantial contribution in reducing GHG emissions,amounting to 14 Gt CO2eq/yr. This alone accounts for 27% of the total reductions required to achieve
the 1.5 compatible emissions target. It thus also leads to a 0.12°C reduction in Global Mean
Temperature, the largest reduction among the land-based scenarios. The intervention also increases
44forest cover by 53 Mha, which occurs as dietary change reduces the pressure on the land system toproduce livestock and the food necessary to feed them. However, the increase in aragonite saturation
rate by 0.04 is proportionally less than expected, as the emissions reductions tend to come from ahigh share of non-CO2 mitigation. Consumptive agricultural water use decreases by 336 km3/yr andhuman-induced N-fixation by 63 Mt N/yr, and improves BII by 0.003. Importantly, LNDfood is uniquein that its ability to synergistically increase forest and BII within the Land Systems Transformation (seerespective section above).

45

6. Combining the Transformations: Synergies, trade-offs, and alternativesocioeconomic assumptions
Motivation and Methods
The world’s energy, land use and production systems are fundamentally interconnected, and so are
the different Global Commons domains. Therefore, the deep Systems Transformations consideredhere can interact with each other inside and across domains in complex ways. As shown in previous
chapters, some transformations that are beneficial to certain Global Commons domains, such as theEnergy Systems transformation, can generate additional pressure on other domains, such as the Land
Biosphere, and slow the effects of other Transformations. Other transformations may have synergistic
effects, enhancing or facilitating each other, while others still explore similar solution spaces anddon’t have additive effects.
We here present a more detailed description of the effects when the Transformations are applied
jointly in an all-transformations (Tall) scenario. To decompose individual effects and examinesynergies and tradeoffs, we also explore intermediate scenarios where the transformations areprogressively applied in combination with each other. We focus on a sequence beginning with theEnergy Systems Transformation, followed by the Land Systems Transformation and its component
interventions, and ending with the Sustainable Production and Consumption Transformation. As theeffects of human activities on the Global Commons are fundamentally affected by GDP development
and population growth rates, we go beyond the all-transformations scenario and estimate the effects
of different assumptions on GDP and population growth as in the Shared Socioeconomic Pathway 1.

Key findings
The scenario in which all proposed transformations are implemented jointly (Tall) would allow
humanity to reverse the degradation of the assessed Global Commons domains to levels very close toor within the safe space of the Planetary Boundaries by 2050. Although even these deep systems
transformations wouldn’t be able to keep warming below 1.5°C without some overshoot in 2050, a
combination of CO2 removal and continued reduction of non-CO2 emissions would revert warming, sothat Global Mean Temperatures would stay below the Paris Agreement target by 2100 and beyond.
However, CO2 concentrations and radiative forcing would still only be stabilised at around current
levels, at which changes in climate harmful to human and natural systems are already observed.
The GHG price levels required for safeguarding the Global Commons domains, especially the Climate,depend crucially on all other measures implemented: In the absence of any other measures, energy
system GHG prices in our scenarios would have to reach around 350 U.S. dollars per ton of CO2
equivalent by 2050 to reach the 1.5°C climate goal. Combining it with other policies, especiallyencouraging the reduction of total demand for high emissions products and services, such asindustrial materials, energy and animal-source foods, and pricing emissions in the land sector lowers
the GHG prices necessary to achieve the same climate target. Demand reductions, although difficult
to implement, ease the cost of transition and have several co-benefits for the land biosphere.
Combined with strong levels of demand reduction, a comprehensive GHG pricing scheme in theenergy and land use could achieve the 1.5°C climate goal with prices as low as 90 U.S. dollars per tonof CO2 equivalent by 2050.
46

As noted in the previous sections, transforming the Energy System has the strongest positive effects
in preventing Climate Change. Among the transformations assessed, it is the only one that can alone
keep Ocean Acidification from crossing its Planetary Boundary. It is also necessary to achieve net-zero
CO2 emissions and stabilise warming into the next century, even though it cannot keep Climate
Change within the safe space by itself.
However, a transformation of energy systems with no limitations on bioenergy reliance fordecarbonising the energy sector will have detrimental effects on Land System Change and Nitrogen
Flows, and push Freshwater Use close to its Planetary Boundary. Such impacts could be counteracted
by jointly transforming the land systems as shown in Section 3.5, but also via specific demand-side
policies on the energy sector to limit its reliance on bioenergy.
Most of these impacts can be counteracted by jointly transforming Land Systems. The Land Systems
transformation can bring Land System Change, Nitrogen Flow and Biosphere Integrity back within
their Planetary Boundaries, substantially reduce Freshwater Use and counteract negative effects fromthe Energy Systems Transformation in these Commons domains. The interventions in the Land
Systems Transformation have a smaller impact on reducing GHG emissions and therefore
safeguarding the climate when applied together with the Energy Systems Transformation than when
considered alone. This is mostly because, if applied without specific policies to prevent, the GHG
pricing on the energy sector leads to a relatively high reliance on bioenergy, particularly
purpose-grown biomass. This leads to higher direct agricultural emissions and increased pressure on
natural land, which makes mitigation from the Land Systems Transformation policies somewhat
harder to achieve.
Reducing the demand for materials in the Sustainable Production and Consumption Transformation
has a much weaker effect on reducing GHG emissions when combined with the already combined
Energy Systems and Land Systems Transformations. This arises from the fact that currently mostemissions in the industry sector are caused by the energy supply, so reducing industrial production
has a weaker effect in reducing emissions in a transformed energy system. However, as the remaining
process emissions are particularly hard to abate, the demand reductions help reduce the costs oftransformation and lead to the relatively low reliance on Carbon Dioxide Removal (CDR) in the alltransformations scenario.
Similarly, assuming smaller population and GDP growth as in SSP1 leads to relatively modest
additional progress in safeguarding the Global Commons domains. Although population and GDP areimportant drivers of global environmental impacts (Riahi et al. 2017, Rockström et al. 2020), theper-capita and per-dollar intensity of impacts is already greatly reduced by the three transformations
implemented before as follows: The Sustainable Production and Consumption Transformation
assumes less demand for materials per person, which reduces the energy demand for the productionof goods. The pricing schemes and land regulations in the Energy and Land systems Transformations
shift these systems to provide energy and agricultural products in more environmentally-efficientways. The shifts in diets and food waste reduction in the Sustainable Food Demand intervention
additionally substantially reduces the amount of agricultural production, and therefore
environmental impacts and land pressure, required to feed a growing population. Similarly, thepushes for more sustainable transport modes and efficient heating systems reduce the per-capita
demand for energy services.
47

Although there can be significant tradeoffs to the Land Biosphere between the components of theLand Systems transformation (as shown in the previous section), the joint implementation of allcomponents of the Land Systems Transformation exhibits a more than additive effect on preserving
biodiversity. This is due to the complementarity of especially the demand-focused diet and foodwaste measures with the systemic approach of disincentivizing loss of natural terrestrial ecosystemsof the Land-based solutions intervention, and to a certain extent also bioenergy production.
The massive transformations assessed here can also have large impacts on agricultural prices, withpotentially important consequences for food security and the justice of these transformations.
Interventions that create additional pressure on the land system tend to increase costs and therefore
prices. Consequently, the Energy Systems transformation can have such an effect when the
production of bioenergy competes with food production. The same is true for the NDCs, which
additionally include large amounts of afforestation that competes for land with agriculture. Lower
material demands from the Sustainable Production and Consumption Transformation reduces
agricultural prices. Since there’s a somewhat heavy reliance on bioenergy on the transformed energy
systems
A key insight from the assessment of the land subtransformation scenarios is that safeguarding theLand Biosphere through supply-side interventions alone can substantially increase the price of food.
The land competition effect is particularly intense for our Land-based solutions subtransformation,that includes a price on CO2 emissions from the conversion of natural land, as well as more stringent
protection of biodiverse regions. The Resource-efficient production systems subtransformation shows
the largest increase of food prices, around 15% in 2050 compared to the NPi scenario, as it increases
production costs in multiple ways. Only a shift in demand patterns, as assumed in the Sustainable
food demand subtransformation, can keep food prices relatively stable at low values over the 21st
century. The Sustainable food demand subtransformation, which models an adoption of the
EAT-Lancet planetary health diet and halving of food waste, dramatically reduces the environmental
impact of peoples’ diets by transitioning away from livestock products.
In general, interventions that only reduce demand, be it for industrial materials (such as theSustainable Production and Consumption Transformation), for unsustainable food products(Sustainable Food demand) or even reduces the size of the economy in general (lower population and
GDP growth in SSP1) can have very substantial effects on safeguarding the assessed Global Commonsdomains. But even within our deep transformations, reduced demand alone will not be sufficient toreach any of the assessed targets. Furthermore, when coupled with structural changes in the systems
themselves, such as the decarbonisation of energy supply and more resource-efficient agricultural
production, these demand-side interventions tend to have a smaller effect than when consideredalone. This arises from the fact that these transformed production systems can fulfil the same
demand with less impact on the Global Commons. However, reductions in demand can befundamental in reducing the societal costs of these production systems transformations, making thesame targets achievable with lower prices for food, energy and GHG emissions for example. Though
as most of the demand reductions assessed require deep behavioural changes, implementing themwould pose a major policy challenge.
Although this study focuses on physical dimensions of the Global Commons domains assessed,
measures that primarily target societal development goals and can also have substantial impacts on
the Global Commons. Many of these interventions can directly or indirectly affect the justice,48

acceptability and feasibility of policies targeting the Global Commons domains, such as improving
global justice in sharing the burden for implementing transformations, gender equality and access to
education.
The system transformations described here are very ambitious. The feasibility of the implementationof such measures will likely depend on well-working governmental institutions and strong
international cooperation. Although each government should control its own transformation strategy,
coordination and compensation mechanisms at the global level are critical given the significant
challenges arising from the profound transformations in the energy, agricultural and industrial
systems, particularly in the global south. International cooperation and strong regional institutions
will be needed to prevent leakages in the impact of policies, especially in the land sector andbetween the Global South and Global North. Moreover, due to the non-predictability of all impacts ofcertain measures, monitoring and readjustment strategies will be necessary and should be includedin the conception of governance strategies aiming to keep the impacts of human activities on the
Global Commons domains within Planetary Boundaries.

GHG prices required for 1.5°C target
In our scenarios, setting a price on greenhouse gas emissions (GHG price) is a crucial intervention. It
is included in both the Energy Systems and Land Systems Transformations. We define the GHG pricepath in most of our scenarios as the optimal, cost-minimising path that can keep warming in the All
Transformations Implemented scenario (SSP2-Tall) below 1.5°C (with limited overshoot). The same
price (fig. 6.2) is applied for GHG emissions both from the Land Use sector as part of the Land
Systems Transformation and from all other sectors as part of the Energy Systems Transformation.
However, since this scenario includes all interventions used in the other scenarios, many of whichease the transition or directly reduce emissions, it can achieve the same climate goal with much
lower GHG prices than any other scenario (Fig 6.1). If GHG pricing is implemented only on energy
systems, the price level required by 2050 is around 350 USD/tCO2eq. However, with all othertransformations applied, this price falls drastically to around 90 USD/tCO2eq. Therefore, the GHG
price path used can be described as one that is high enough to keep warming below 1.5°C if alltransformations are applied, but not necessarily so if only parts of them are.

49

Fig. 6.1: Trajectories of GHG emissions pricing required for global mean temperature change to remain under
1.5°C with limited overshoot in: the all-transformations scenario (red) and; in a scenario where prices areapplied only in the energy sector and in the absence of any other interventions (blue).

The GHG price however differs by regions. This differentiation is made based on the GDP per capita
of each region in earlier years, so that developing regions face lower prices initially. The prices
eventually converge to a uniform global price of 91 USD/t CO2eq in 2050, and reach 219 USD/t CO2eq.

50

Fig. 6.2: Prices on GHG emissions (per ton of CO2 equivalent), applied as part of the Energy Systems and Lands
System Transformations. Region codes: CAZ: Canada, NZ, Australia; CHA: China; EUR: EU28 Europe; IND: India;
JPN: Japan; LAM: Latin America and the Caribbean; MEA: Middle East, North Africa, Central Asia; NEU:
Non-EU28 Europe; OAS: Other Asia; REF: Countries from the reforming economies of the former Soviet Union;
SSA: Sub-Saharan Africa; USA; United States of America.

Effects on the Climate system and the Cryosphere

Fig. 6.3: Effects of the combined transformations on yearly GHG emissions. For comparison, the gray rectangles
on the left side show the evolution of the indicator between 2015 and 2050 in the current policies
implemented (SSP2-NPi) scenario. The other rectangles represent the decomposition of the effects, relative to
the NPi scenario, of the Energy Systems Transformation (yellow), followed by the Land Systems Transformation(Tland, dark green) with its subtransformations (light green) and the Sustainable Production and Consumption
Transformation (blue). The grey rectangle on the right side shows the state of the all transformations (SSP2-Tall)scenario in 2050. The magenta rectangle on the right side shows the additional effects of SSP1 assumptions on
GDP and population growth.

The All transformations scenario (Tall) can, by design, keep warming below 1.5ºC by 2100 witharound 0.1ºC overshoot in 2050. Therefore, we use the emissions trajectory of the
all-transformations scenario as intermediate targets to compare progress in scenarios with fewer
interventions. GHG emissions in that scenario are at 11 Gt CO2eq/yr in 2050, and net-zero CO2emissions are reached in 2070.
As described in Section 2, under current policies (NPi), GHG emissions (Fig. 6.3) would reach 64 Gt
CO2eq/yr by 2050, and the current NDC commitments would reduce them by 22 GtC CO2eq/yr, lessthan half the reduction needed to achieve the target value of 11 Gt CO2eq/yr. We set thisintermediate target for emissions based on our all-transformations scenario, in which global mean
temperature change remains below 1.5C by 2100 with limited overshoot. Transforming the energy
51system can close more than 70% of that gap, mainly through reductions in CO2 emissions in theenergy and industry sectors due to the introduction of emissions pricing.
The interventions in the Land Systems Transformation have a smaller impact on reducing GHG
emissions when applied together with the Energy Systems Transformation, 11 Gt CO2eq/yr, butnevertheless adds another 20% to closing the gap. This is mostly because, if applied without specificpolicies to prevent, the GHG pricing on the energy sector leads to a relatively high reliance on
bioenergy, particularly purpose-grown biomass (20 EJ/yr in 2050 and 288 EJ/yr in 2100 from energy
crops). This leads to higher direct agricultural emissions and increased pressure on natural land,
which makes mitigation from the Land Systems Transformation policies somewhat harder to achieve.
For this reason, the effect of the overall transformation, as well as of its component interventions, in
reducing GHG emissions by 2050 is around 10 Gt CO2eq/yr weaker than when they are applied on topof the scenario with only the currently implemented policies. The land scarcity induced by theconservation policies in the Land Systems Transformation also increases production prices forbioenergy, which leads to a somewhat lower reliance on energy crops by the end of the century (188
EJ/yr), but little effect in 2050.
Reducing the demand for materials in the Sustainable Production and Consumption Transformation
has a much weaker effect on reducing GHG emissions when combined with the already combined
Energy Systems and Land Systems Transformations. This arises from the fact that currently mostemissions in the industry sector are caused by the energy supply, and a smaller but still substantial
share by the industrial processes themselves. Reducing the demand for industrial products leads toless production and proportionally reduces GHG emissions from both sources. But if the energy
system is transformed, this already reduces the emissions needed for the production of one unit ofindustrial goods. Therefore, reducing the total demand for these goods has a weaker effect inreducing emissions in a transformed energy system. However, as the remaining process emissions are
particularly hard to abate, the demand reductions help reduce the costs of transformation and leadto the relatively low reliance on Carbon Dioxide Removal (CDR) in this scenario.

52

Fig. 6.4: Effects of the combined transformations on global mean temperature (GMT) change. For comparison,
the gray rectangles on the left side show the evolution of the indicator between 2015 and 2050 (top) or 2100
(bottom) in the current policies implemented (SSP2-NPi) scenario. The other rectangles represent thedecomposition of the effects, relative to the NPi scenario, of the Energy Systems Transformation (yellow),followed by the Land Systems Transformation (Tland, dark green) with its subtransformations (light green) andthe Sustainable Production and Consumption Transformation (blue). The grey rectangle on the right side shows
the state of the all transformations (SSP2-Tall) scenario in 2050 (top) or 2100 (bottom). The magenta rectangle
on the right side shows the additional effects of SSP1 assumptions on GDP and population growth.

Similarly, assuming smaller population and GDP growth as in SSP1 leads to a relatively modest
additional reduction in GHG emissions (1.5 Gt CO2eq/yr). Although population and GDP areimportant drivers of global environmental impacts (Riahi et al. 2017, Rockström et al. 2020), theper-capita and per-dollar intensity of emissions is already greatly reduced by the threetransformations implemented before as follows: The Sustainable Production and Consumption
Transformation assumes less demand for materials per person, which reduces the energy demand forthe production of goods. The GHG pricing schemes in the Energy and Land systems Transformations
shift these systems to provide energy and agricultural products in more emissions-efficient ways. The
shifts in diets and food waste reduction in the Sustainable Food Demand intervention additionallysubstantially reduces the amount of agricultural production, and therefore agricultural emissions and53

land pressure, required to feed a growing population. Similarly, the pushes for more sustainabletransport modes and efficient heating systems reduce the per-capita demand for energy services.
The effects of the transformations on preventing Global Mean Temperature change broadly follow
those on reducing equivalent GHG emissions, but with different short- and long-term dynamics. By
2100, the scenario with all transformations is able to limit warming to below 1.5°C, with the Energy
Systems Transformation being responsible for preventing around 70% of the warming that would
happen under current policies. However, the Land Systems Transformation is particularly importantto minimise the overshoot of the 1.5°C in the short term due to its ability to quickly reduce methane
emissions. Methane is a strong greenhouse gas, but has a relatively short lifetime in the atmosphere.
Therefore, the earlier methane reductions of the Land Systems Transformation result in stronger
reductions in short-term warming, having the strongest effect around 2030 when the target is firstovershot in most scenarios (Fig.6.5). However, the Energy Systems Transformation is the only one
that is able to, alone, reach net-zero CO2 emissions by 2100 and prevent warming to continue wellinto the next century.

Fig. 6.5: XXI century trajectories of median estimates of Global Mean Temperature change relative to thepreindustrial period for the scenarios with only the currently implemented policies (NPi), only the individualtransformations (Tene, Tland, Tpc) and with all transformations combined (Tall). The horizontal black line shows
the 1.5°C target.

Effects on the Oceans
The aragonite saturation rate is a direct proxy for the Planetary Boundary of Ocean Acidification, withlower values being detrimental to the stability of marine ecosystems. The main human-driven causeof ocean acidification is the increase in the concentration of CO2 in the atmosphere caused by CO2emissions. A large fraction of the CO2 emitted by human activities is eventually dissolved in the ocean
waters, which increases their acidity and lowers the aragonite saturation rate.

54

Fig. 6.6: Effects of the combined transformations on Aragonite Saturation Rate. For comparison, the grayrectangles on the left side show the evolution of the indicator between 2015 and 2050 (top) or 2100 (bottom)
in the current policies implemented (SSP2-NPi) scenario. The other rectangles represent the decomposition of
the effects, relative to the NPi scenario, of the Energy Systems Transformation (yellow), followed by the Land
Systems Transformation (Tland, dark green) with its subtransformations (light green) and the Sustainable
Production and Consumption Transformation (blue). The grey rectangle on the right side shows the state of the
all transformations (SSP2-Tall) scenario in 2050 (top) or 2100 (bottom). The magenta rectangle on the right sideshows the additional effects of SSP1 assumptions on GDP and population growth.

Since it has the strongest effects in reducing CO2 emissions, the Energy Systems Transformation is
responsible for the largest positive impact on the aragonite saturation rate. With only the current
NDCs, aragonite saturation would fall below the target value already in 2050. In fact, only scenariosthat include the Energy Systems Transformation remain consistently above the target value
throughout the century (fig 6.7). Therefore, transforming the energy systems is essential to keep
Ocean Acidification within relatively safe levels.
The interactions between the Energy Systems Transformation and the other two mentioned for GHG
emissions similarly apply for Ocean Acidification. The Land Systems Transformation has a substantial
positive effect on aragonite saturation, although it’s just about half as strong when applied alongside
the Energy Systems Transformation. This is due to the increased bioenergy demand induced by thelatter. All its component interventions reduce CO2 emissions and have individually positive impacts,55

with the Land-based solutions having the strongest. Similarly, the reduced energy and material
demand induced by the Sustainable Production and Consumption Transformation has a diminishedeffect in reducing CO2 emissions when the energy systems are already decarbonized, and therefore asmaller but still positive impact on aragonite saturation.
Also, for similar reasons, assuming lower GDP and population growth as in the SSP1 scenario has apositive but modest effect on increasing aragonite saturation rate when assessed on top of alltransformations. Each transformation directly or indirectly reduces the CO2 emissions needed to
produce one unit of GDP or to fulfil one person’s needs, either by reducing demand for food,materials and energy or by producing them in more efficient ways.

Fig. 6.7: XXI century trajectories of global mean aragonite saturation rate for the scenarios with only thecurrently implemented policies (NPi), only the individual transformations (Tene, Tland, Tpc) and with alltransformations combined (Tall). Lower values of aragonite saturation rate lead to higher impacts on marine
ecosystems.

Effects on the Ozone Layer
All our scenarios, including the national policies implemented (NPi) scenario, include full compliancewith the Montreal Protocol. Under this assumption, emissions of ozone-depleting substances arephased out quickly, leading to the gradual recovery of the Ozone Layer and co-benefits to the climate
system by avoiding warming. Effective Equivalent Stratospheric Chlorine (EESC), an indicator of thepotential damage of anthropogenic activity on the health of stratospheric ozone, returns to pre-1980
levels (around 2000 ppt) between 2030 and 2050 (Fig. 6.8). This finding is broadly in agreement withthose of the latest UN Scientific Assessment of Ozone Depletion (WMO 2022), which finds that undercontinued compliance the near-global average levels of tropospheric column ozone should return topre-1980 levels by around 2040.

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Fig. 6.8: Effects of the base national policies implemented (NPi) assumptions on Effective Equivalent
Stratospheric Chlorine (EESC), a measure of ozone-depleting substances in the stratosphere. All our scenarios,
including NDC, assume full compliance with the Montreal Protocol’s reductions in the emissions ofozone-depleting substances.

Effects on the Land Biosphere
Forest cover
The different transformations show synergies as well as trade-offs regarding the future developmentof forest cover. If all transformations are applied jointly in the Global Commons stewardship scenario,
forest cover increases compared to 2015 and reaches the target level of 4300 Mha in 2050, definedas 75% of original forest cover (see Annex). This is made possible especially by combining different
interventions in the land and food systems. These together increase forest cover by 428 Mha andmore than compensate the projected decreases caused by the continuation of current policies andthe increased bioenergy demand from the Energy Systems Transformation.
The current NDCs include afforestation commitments that unfold a strong positive impact on forest
cover in the short-term. However, forest cover in the NDC scenario is again slightly below the value of2015 in the middle of the century, and commitments are not successful in stopping deforestation in
the long-term, due to leakage effects and resulting loss of unprotected natural forests. While theland-based NDCs are largely beneficial for the forest cover indicator, they are not enough tocounteract the current trends in deforestation, and trade-offs from NDC implementation in othersectors occur due to the resulting substantial increase in demand for purpose-grown bioenergy crops.
The Energy Systems Transformation additionally drives demand for second generation bioenergy with resulting pressures on the land systems, and having detrimental consequences for forest cover.
The land-based solutions subtransformation is critical to prevent trade-offs from mitigation measuresin the energy system such as bioenergy production, especially in the long-term. If applied on top of
the Energy Systems Transformation, it leads to effects on aggregate forest cover in 2050 similar to
those of the land sector commitments of the NDCs, yet involving different underlying dynamics. The
temporal dynamics in the NDC scenario are driven mainly by an early increase in managed forest but
57

simultaneous unabated decline in natural forest cover. In contrast, land-based mitigation measures
such as GHG emissions pricing from natural land conversion and additional land protection schemes
stabilise forest cover throughout the century, halt further loss of primary forests, and prevent the
majority of decline in secondary natural forests. Thus, stabilising forest cover on top of the Energy
Systems Transformation is realised with only a small contribution of additional afforestation, andgoes hand in hand with a relative reduction in bioenergy deployment compared to accomplishing theenergy transformation without such price- and regulation-based land protection measures.
If applied on top of the Energy System Transformation, the resource efficiency subtransformation in
the land sector slightly increases forest cover in the first half of the century. This is due to synergies oflower demand for pastures in the wake of livestock system intensification with biomass use in theenergy system.
The sustainable food demand subtransformation increases forest cover by a substantial amount, but
it is less effective when bundled with mitigation efforts in the energy system. This is mostly caused bybioenergy crops competing for the land freed by the reduced food production.
Combining the individual subtransformations within the Land Systems Transformation yields a morethan additive effect. This is due to synergies, created by both temporal complementarity (different
emphases in the long- and short-term impacts) and complementarity of the underlying processes,
such as in the combination of the food system transformation and land-based climate change
mitigation actions. This synergistic interplay between the subtransformations in the land sector,
however, is similar to their behaviour without implementation of energy system interventions.
The effect of the Sustainable Production and Consumption Transformation on forest cover is positiveand much more substantial when applied on top of the Energy and Land Systems Transformations.
With the decarbonisation of the energy system, industrial production relies much more on biofuelsand bioenergy-based electricity than under current policies. Therefore, the reduction of industrial
activity has a smaller effect on GHG emissions as mentioned before, but a much larger effect on
reducing bioenergy demand and therefore reducing pressure on the land systems.
Finally, assuming lower population and GDP growth according to the more sustainablesocio-economic pathway (SSP1) leads to a relatively modest increase in forest cover on top of alltransformations. as these already reduce the demand for agricultural products as well as the
detrimental impacts of biomass production on forests.

58

Fig. 6.9: Effects of the combined transformations on total global Forest Cover. For comparison, the grayrectangles on the left side show the evolution of the indicator between 2015 and 2050 in the current policies
implemented (SSP2-NPi) scenario. The other rectangles represent the decomposition of the effects, relative to
the NPi scenario, of the Energy Systems Transformation (yellow), followed by the Land Systems Transformation(Tland, dark green) with its subtransformations (light green) and the Sustainable Production and Consumption
Transformation (blue). The grey rectangle on the right side shows the state of the all transformations (SSP2-Tall)scenario in 2050. The magenta rectangle on the right side shows the additional effects of SSP1 assumptions on
GDP and population growth.

Human-induced nitrogen fixation
Our transformation scenarios demonstrate the profound importance of measures increasing
resource-use efficiency (LNDreseff) within the agricultural sector – particularly in tandem with a shift
towards a flexitarian EAT-Lancet diet (LNDfood) – if the Planetary Boundary for human-induced
nitrogen fixation is to be met. Indeed, these transformations alone are able to mitigate N-fixation tolevels approaching the Planetary Boundary. However, coupling these measures with the Energy
Systems Transformation (Tene) and especially the Sustainable Production and Consumption
Transformation (Tpc), the Planetary Boundary is achieved. Without these critical land interventions,transformations targeted solely at the energy sector will only exacerbate the problem of
human-induced nitrogen fixation.
Meeting the NDCs increases the level of human-induced N fixation through two pathways. Directly,
without disincentivizing emissions from the land use sector, meeting the NDCs will result in thesignificant deployment of N-intensive bioenergy crops. Indirectly, mirroring the increase in
consumptive agriculture use, a reliance on bioenergy will drive competition for land, inducing
cropland expansion necessary to meet food and bioenergy demand. The combined effect increases
our projections of human-induced N fixation by 7% (14 MtN/yr) over the NPi alone in 2050. In
contrast, a full Energy Systems Transformation (Tene), despite also relying heavily on bioenergy, leads
to a lower total demand for biomass than that of the NDC scenario (but still higher than NPi). This isdue to the more sustainable assumptions in the transport sector including electrification, which
reduces the demand for biofuels. This mitigates – though does not entirely eliminate - the increase in
N fixation compared to the NPi scenario.

59

Fig. 6.10: Effects of the combined transformations on Human-induced N fixation. For comparison, the grayrectangles on the left side show the evolution of the indicator between 2015 and 2050 in the current policies
implemented (SSP2-NPi) scenario. The other rectangles represent the decomposition of the effects, relative to
the NPi scenario, of the Energy Systems Transformation (yellow), followed by the Land Systems Transformation(Tland, dark green) with its subtransformations (light green) and the Sustainable Production and Consumption
Transformation (blue). The grey rectangle on the right side shows the state of the all transformations (SSP2-Tall)scenario in 2050. The magenta rectangle on the right side shows the additional effects of SSP1 assumptions on
GDP and population growth.

Transformations in the land sector targeting either the land-based NDCs (LNDndc) or land-based
solutions (LNDlbs) do little to mitigate human-induced nitrogen fixation, as they relocate foodproduction rather than either reducing the resource-intensity of food demand (LNDfood) or
increasing the resource efficiency of food production (LNDreseff). Applied on top of the Energy
Systems Transformation, a transition towards more plant-based diets or increasing the efficiency of N
usage decreases N pollution by 29% and 37% respectively. When integrated together into the fullLand Systems Transformation (Tland), the Planetary Boundary for human-induced nitrogen fixation iswithin reach; in total fixation reaches 95 Mt N/yr, near the Planetary Boundary of 90 Mt N/yr. Furthertransforming the industrial sector through the Sustainable Production and Consumption
Transformation (Tpc) reduces total N-fixation by 5 Mt N/yr, successfully lowering total
human-induced N fixation to just slightly above the Planetary Boundary. Integrating SSP1
assumptions of population and GDP further decreases total fixation to 83 MtN/yr, as demand for
agricultural and industrial products is reduced. However, compared to the enormous potential for
efficiency gains and dietary shift, integrating more optimistic SSP assumptions makes relatively little
difference in the final accounting for N-fixation.
Like consumptive agricultural water use, the boundary for N-fixation is highly relevant in a
spatially-explicit context. Thus, quantifying regional boundaries will be critical for future work. Recent
literature accounting for the spatial variability of both ecosystems' sensitivity to nitrogen pollution
and agricultural nitrogen losses has found that incorporating these regional boundaries likely
decreases the safe operating space for nitrogen usage. This suggests a further increase in thenecessity of enhancing nitrogen use efficiency, as well as the coordinated reduction of
non-agricultural nitrogen sources (Schulte-Uebbing et al. 2022).

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Fig. 6.11: Effects of the combined transformations on Biodiversity Intactness Index. For comparison, the grayrectangles on the left side show the evolution of the indicator between 2015 and 2050 in the current policies
implemented (SSP2-NPi) scenario. The other rectangles represent the decomposition of the effects, relative to
the NPi scenario, of the Energy Systems Transformation (yellow), followed by the Land Systems Transformation(Tland, dark green) with its subtransformations (light green) and the Sustainable Production and Consumption
Transformation (blue). The grey rectangle on the right side shows the state of the all transformations (SSP2-Tall)scenario in 2050. The magenta rectangle on the right side shows the additional effects of SSP1 assumptions on
GDP and population growth.

Biodiversity Intactness
Biodiversity intactness as measured by the BII indicator will further decrease as a result of conversionof natural land into managed land and an increasing relative importance of cropland compared to
pasture within agricultural landscapes, if no interventions are to be taken against land system change.
When climate mitigation measures include biomass as energy carrier and are implemented in theenergy sector without adequate precautions against detrimental impacts of large-scale bioenergy
production on the biosphere, BII will even decrease beyond the level of the NPi scenario, especially inthe long-term. These trade-offs from energy system measures on the land system are observable
both for the Energy Systems Transformation as well as for the NDC scenario mainly in the second halfof the century.
When all system transformations are implemented jointly in the Global Commons Stewardshipscenario, the BII increases relative to 2015, exceeds the target of 0.8 in 2050 (see Annex 2), andcontinues to improve throughout the end of the century, largely due the Land Systems
Transformation and the complementary benefits of ambitious dietary changes towards healthynutrition and land-based solutions to mitigate climate change in the land sector. Although current
land-based NDCs also slightly counterbalance trade-offs from large-scale bioenergy production thatare part of the mitigation measures in the NDC scenario and the Energy Systems Transformation,
positive effects on BII are small, and less perceivable than their positive effects on forest cover. The
regionally diverse pledges for afforestation and avoided land conversion cannot systematically
prevent leakage effects, both in terms of teleconnections and in terms of affected land cover types,
resulting in a relative shift from natural to managed forests and loss of non-forested land andpastures, with all described leakage channels negatively affecting biodiversity intactness. Despite
small positive effects on forest cover, the resource efficiency subtransformation in the land sector
61does not improve BII in the first half of the century, due to a stronger expansion of cropland in thewake of livestock system intensification with a higher reliance on cropland-based feed and less
irrigation. In the second half of the century, there are, however, small synergies between bioenergy
demand and a higher availability of pastures for bioenergy plantations, which averts pressures fromnatural land cover types and improves BII outcomes, if resource efficiency interventions are applied
on top of the Energy Systems Transformation.
The land-based solutions subtransformation is the single most important bundle of measures tofoster progress towards the BII target, which more than counterbalances the negative developments
under the NPi scenario, stabilising the BII in the first half of the century and slightly bending the curve
until the end of the century, regardless of whether the interventions of the Energy Systems
Transformation are in place. Since the latter exhibits, as individual strategy, detrimental effects on BII
beyond the NPi scenario, the interventions included in the LNDlbs scenario are especially relevant in
the context of multi-sector pathways, showing a higher relative improvement of BII in combination
with the Energy Systems Transformation compared to effects based on the NPi scenario. Pricing GHG
emissions from natural land conversion exert positive impacts on BII especially due to the resulting
preservation of remaining primary forests and incentives to curb cropland expansion, which also
makes bioenergy production more expensive and somewhat dampens the high demand for biomass
from the energy sector. In contrast to land-based solutions, the positive impacts of the foodtransformation in combination with the Energy Systems Transformation on BII are comparable to its
effects as individual intervention and do not moderate bioenergy deployment. The transition to
healthy diets and low food waste represents the second most important subtransformation forimproving BII, while also substantially slowing down the speed of agricultural intensification anddecreasing the size of the livestock sector, with many potential co-benefits on biodiversity beyond
those from land use change, such as the use of pesticides and landscape homogenisation, which are
not quantified in the here presented work.
The joint implementation of all components of the Land Systems Transformation exhibits a more thanadditive effect, due to the complementarity of especially the demand-focused diet and food waste
measures with the systemic approach of disincentivizing loss of natural terrestrial ecosystems in the
LNDlbs scenario and to a certain extent also bioenergy production. The land-based NDCs additionallycontribute early action to increase afforestation efforts. The Sustainable Production andConsumption Transformation, applied as the last system transformation, has a positive impact on
Land System Change and BII by reducing mitigation pressures in the energy system and thus
dependence on bioenergy, as opposed to applying it on top of current policies with little deploymentof bioenergy. Finally, following population and GDP growth of the more sustainable socio-economic
pathway of SSP1 turns out to have strongest benefits for BII after LNDlbs and LNDfood, mainly due tothe lower biomass requirements for food, feed and biomass for energy use.

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Fig. 6.12: Effects of the combined transformations on Consumptive agricultural water use. For comparison, thegray rectangles on the left side show the evolution of the indicator between 2015 and 2050 in the current
policies implemented (SSP2-NPi) scenario. The other rectangles represent the decomposition of the effects,
relative to the NPi scenario, of the Energy Systems Transformation (yellow), followed by the Land Systems
Transformation (Tland, dark green) with its subtransformations (light green) and the Sustainable Production
and Consumption Transformation (blue). The grey rectangle on the right side shows the state of the alltransformations (SSP2-Tall) scenario in 2050. The magenta rectangle on the right side shows the additional
effects of SSP1 assumptions on GDP and population growth.

Consumptive agricultural water use
Our analysis shows that changes in consumptive agricultural water use follows a pattern similar toother global indicators that reflect agricultural inputs. For instance, similar to human-induced
nitrogen fixation, the Energy Systems Transformation (Tene) without coordinated protections against
an over-reliance on bioenergy production will put extreme pressure on the agricultural system tomeet climate targets. In this case, consumptive agricultural water use increases by 17% (332 km3/yr),reaching levels slightly below the prescribed boundary of 1980 km3/yr. This effect emerges because,
despite being limited to rainfed production, bioenergy production displaces food production towards
marginal croplands, thus indirectly increasing irrigation to meet food demand. The three land-based
subtransformations have strong synergies that, when applied together on top of the Energy Systems
Transformation, reduce pressure on the land system such that bioenergy deployment can coexist
with food production, and reaching the targets for other global indicators such as biodiversity andforest cover remain possible.
Avoiding negative leakage effects related to bioenergy requires concerted, ambitious, and global
efforts to shift patterns of food demand towards sustainable consumption and away from resource
and land-intensive production. Livestock production necessitates significant water, both as a primary
input to the animals themselves, but also for growing feed crops. Thus, large-scale reduction inlivestock consumption reduces two factors responsible for substantial shares of water use. Thus, thistransformation is a trade-off free solution to the overconsumption of agricultural water.
Resources efficiency gains, as modelled in the Resource-efficient production systems
subtransformation, is another critical component of a Land Systems Transformation respecting
boundaries for water use, but suffers a severe negative externality when applied in isolation. This
subtransformation introduces critical efficiency improvements, as well as necessary restrictions on
63

environmental flow violations. Thus, it leads to strong reductions in agricultural water consumption.
However, when coupled with the Energy Systems Transformation alone, it leads to significant
cropland expansion. This is because, if there is no possibility of intensifying food crops, the growing
demand for food can only be met by expanding the croplands and relying more on rain-fed rather
than irrigated yields.
In 2050, the Land-based solutions (LNDlbs) subtransformation appears relatively unimportant interms of agricultural water use. If applied in isolation, it would however drastically increase the usageof agricultural water over the second half of the century. The reason is that it introduces a CO2 pricein the agricultural sector that includes emissions from land conversion. Thus, even as demand
increases, it is unprofitable to convert forests to cropland, and water use is intensified on existing
croplands instead. On the other hand, integrated into the Land Systems Transformation, land-based
solutions are critical to balance the Resource-efficient production systems subtransformation.
The integration of all three land-based subtransformations dampens their respective negativeside-effects, and successfully offsets the consequences of the Energy Systems Transformation
scenario. Water usage reaches levels lower than those seen in 2015, despite the pressure oflarge-scale bioenergy production on the agricultural system. Even cropland area is held nearly
constant from today. Lastly, adopting SSP1 population and GDP trajectories has negligible impact on
shifting aggregate water usage.
Although all scenarios fall within the Planetary Boundary in 2050, water availability, and its
consumptive use, is heterogeneously distributed. Therefore, in many regions, an unconstrainedenergy transition will almost inevitably push the availability of water for agriculture below regional
thresholds, even if the global boundary is apparently safe from transgression. These regional impacts
endanger not only critical ecosystem services but also human health and wellbeing. Thus,
incorporating these "regional boundaries" is a necessary step for future research and fundamental
for policymakers focusing on regional planning.

Effects on agricultural prices
Although this study focuses on the physical outcomes of the transformations in safeguarding the
Global Commons domains, the massive transformations assessed here can have large impacts on
agricultural prices, with potentially important consequences for food security and the justice of thesetransformations. For this reason, we also analyse the effects of the different transformations on an
agricultural commodity price index. This is the production-weighted average price index of
agricultural commodities (all consumer products, including food and bioenergy) with respect to 2020.

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Fig. 6.13: Effects of the combined transformations on agricultural commodity prices. Values are shown for an
aggregated price index relative to the year 2020. For comparison, the gray rectangles on the left side show theevolution of the indicator between 2015 and 2050 in the current policies implemented (SSP2-NPi) scenario. The
other rectangles represent the decomposition of the effects, relative to the NPi scenario, of the Energy Systems
Transformation (yellow), followed by the Land Systems Transformation (Tland, dark green) with its
subtransformations (light green) and the Sustainable Production and Consumption Transformation (blue). The
grey rectangle on the right side shows the state of the all transformations (SSP2-Tall) scenario in 2050. The
magenta rectangle on the right side shows the additional effects of SSP1 assumptions on GDP and population
growth.

Due to continued improvements in agricultural technologies, agricultural food prices tend to decline
by 2050 in the national policies implemented (NPi) scenario.
Interventions that create additional pressure on the land system tend to increase costs and therefore
prices. Consequently, the Energy Systems transformation can have such an effect when the
production of bioenergy competes with food production. For the same reason, the nationallydetermined contributions (NDCs) for decarbonizing energy systems lead to pressure on food prices.
Interventions aimed at protecting land also create pressures on agricultural prices, as they limit the
expansion of agriculture. That is the case of the land-based NDCs (LNDndc), which further increase
food prices as forested land that could otherwise be converted into cropland is restricted fromexpansion. Land-based solutions (LNDlbs) is yet more extreme, because it includes a price on CO2emissions from the conversion of natural land, as well as more stringent protection of biodiverse
regions. These would further reduce the total land available for cropland and pasture expansion.
The Resource-efficient production systems subtransformation shows the largest increase of foodprices. This striking result emerges as a price on non-CO2 GHG emissions is introduced into theagricultural sector, in addition to protections on freshwater environmental flows. Both measuresincrease the price of food production, especially for livestock products which produce significant
non-CO2 emissions. Protection of freshwater environmental flows, and the subsequent displacementof irrigated areas leads to significant conversion of land to cropland, further increasing food prices.
A key insight from the assessment of the land subtransformation scenarios is that safeguarding theLand Biosphere through supply-side interventions alone will increase the price of food. Only a shift indemand patterns, as assumed in the Sustainable food demand subtransformation (LNDfood), can65keep food prices relatively stable at low values over the 21st century. The Sustainable food demand
subtransformation, which models an adoption of the EAT-Lancet planetary health diet and halving offood waste, dramatically reduces the environmental impact of peoples’ diets by transitioning awayfrom livestock products. But since these products also tend to be the most expensive – in addition to
being the most polluting – reducing the share of livestock products leads to large decreases in theprice of food by 2050.
Adopting this transition on top of the Energy Systems Transformation and the other Land Systems
subtransformations enables significant progress towards the Planetary Boundaries while even slightly
decreasing the food prices by around 5% relative to the prices in the national policies implemented(NPi) scenario. This result affirms that the transition towards healthy, affordable diets is one of themost pressing issues for policymakers to address into the 21st century. Only measures targeting shifts
to more sustainable diets and reducing food waste will reduce pressure on the land system andcreate leeway for implementing policies which preserve the long-term health of the Global Commonsdomains without negatively impacting livelihoods and human wellbeing.
Lower material demands from the Sustainable Production and Consumption Transformation also
reduces agricultural prices. Since there’s a somewhat heavy reliance on bioenergy on thetransformed energy systems, the reduction in industrial demand leads to less pressure on land andultimately affects prices.
Lastly, adopting SSP1 assumptions for population and GDP expectedly makes a large difference in the
agricultural prices, reducing them by more than 5% relative to the All-transformations scenario (thatconsiders SSP2 assumptions). This is largely a consequence of the reduced demand from a population
smaller by around 0.5 billion people in 2050. However, it’s interesting to note that even thissubstantial reduction in population has a much smaller effect on food prices than that of shifting tomore sustainable food consumption patterns.

66References[GCSF 2022] Center for Global Commons. 2022. Safeguarding the Global Commons for humanprosperity and environmental sustainability - The Global Commons Stewardship Framework.
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68AnnexAnnex 1: Model descriptions
We use and extend the PIK integrated assessment modelling (PIAM) framework to simulate the
System Transformations, interactions between them, and their impacts on the Global Commons. The
core of the framework consists of the energy-economy-climate model REMIND coupled to thespatially explicit land-system model MagPIE. The core REMIND-MagPIE models are complemented by
MAGICC, a simple global climate model, and LPJmL, a vegetation and hydrology model.
Here we present brief descriptions of the core REMIND-MagPIE, MAGICC and LPJml models, alongwith lists of references that provide more detailed descriptions as well as examples of successful
applications.

Annex Fig. 1.1: Overview of the modelling framework, showing some of the simulated processes and linkages
between models.

REMIND - REgional Model of INvestments and Development
REMIND (REgional Model of Investment and Development) is a numerical model that represents the
future evolution of the world economies with a special focus on the development of the energy
sector and the implications for our world climate. The goal of REMIND is to find the optimal mix ofinvestments in the economy and the energy sectors of each model region given a set of population,technology, policy and climate constraints. It also accounts for regional trade characteristics on
goods, energy fuels, and emissions allowances. All greenhouse gas emissions due to human activities
are represented in the model.
More information can be found in the sources below:●●●

https://rse.pik-potsdam.de/doc/remind/2.1.3
https://github.com/remindmodel/remind
https://www.iamcdocumentation.eu/index.php/Model_Documentation_-_REMIND-MAgPIE
69

●

●

Luderer, G., Bauer, N., Baumstark, L., Bertram, C., et al.: REMIND - REgional Model ofINvestments and Development, https://github.com/remindmodel/remind,
10.5281/zenodo.4091409. https://doi.org/10.5281/zenodo.4091409,
https://www.pik-potsdam.de/research/transformation-pathways/models/remindBaumstark, L., Bauer, N., Benke, et al. (2021). REMIND2.1: Transformation and innovation
dynamics of the energy-economic system within climate and sustainability limits. Geoscientific
Model Development Discussions, 1–50. https://doi.org/10.5194/gmd-2021-85

MAgPIE - Model of Agricultural Production and its Impact on the Environment
MAgPIE (Model of Agricultural Production and its Impact on the Environment) is a global
partial-equilibrium model used to analyse potential developments in the land system, given different
scenarios of socio-economic development and climate change. A spatially-explicit model, it minimises
the total costs of the land-use sector (production, investment and transportation) under
spatially-explicit biogeophysical constraints, while meeting demand for regional and globally-tradedagricultural goods. Demand incorporates country-level food intake, food waste and dietarycomposition based on projected future scenarios of GDP, demographic structure and population
growth. Biogeophysical constraints, e.g. crop yield potentials and water availability, are derived fromthe dynamic vegetation model LPJmL(Lund-Potsdam-Jena managed Land) on a 0.5°x0.5° grid scale.
More information can be found in the sources below:
●
●
●

●

https://rse.pik-potsdam.de/doc/magpie/4.4.0/
https://github.com/magpiemodel/magpie
Dietrich J, Bodirsky B, Weindl I, Humpenöder F, Stevanovic M, Kreidenweis U, Wang X, Karstens
K, Mishra A, Beier F, Molina Bacca E, Klein D, Ambrósio G, Araujo E, Biewald A, Lotze-Campen H,
Popp A (2020). “MAgPIE - An Open Source land-use modeling framework - Version 4.3.0.” doi:
10.5281/zenodo.1418752,
https://doi.org/10.5281/zenodo.1418752),
https://github.com/magpiemodel/magpie.
Dietrich, J. P., Bodirsky, B. L., Humpenöder, F., et al. (2019): MAgPIE 4 – a modular open-source
framework for modeling global land systems, Geosci. Model Dev., 12, 1299–1317,
https://doi.org/10.5194/gmd-12-1299-2019.

MAGICC - Model for the Assessment of Greenhouse Gas Induced Climate Change
MAGICC is a simple/reduced complexity climate model. It consists of a hemispherically averaged
upwelling-diffusion ocean coupled to an atmosphere layer and a globally averaged carbon cycle
model. MAGICC has been widely used in various IPCC Assessment Reports.
●●

Meinshausen, M., Raper, S. C. B., & Wigley, T. M. L. (2011). Emulating coupled atmosphere-oceanand carbon cycle models with a simpler model, MAGICC6 – Part 1: Model description andcalibration.
Atmospheric
ChemistryandPhysics,
11(4),
1417–1456.
https://doi.org/10.5194/acp-11-1417-2011
Meinshausen, M., Wigley, T. M. L., & Raper, S. C. B. (2011). Emulating atmosphere-ocean andcarbon cycle models with a simpler model, MAGICC6 - Part 2: Applications. Atmospheric
Chemistry and Physics, 11(4), 1457–1471. https://doi.org/10.5194/acp-11-1457-201170

LPJmL - Lund-Potsdam-Jena managed Land dynamic global vegetation, hydrology and cropmodel
The model LPJmL ("Lund-Potsdam-Jena managed Land") is designed to simulate vegetation
composition and distribution as well as stocks and land-atmosphere exchange flows of carbon andwater, for both natural and agricultural ecosystems. Using a combination of plant physiologicalrelations, generalized empirically established functions and plant trait parameters, it simulates
processes such as photosynthesis, plant growth, maintenance and regeneration losses, fire
disturbance, soil moisture, runoff, evapotranspiration, irrigation and vegetation structure.
●●https://www.pik-potsdam.de/en/institute/departments/activities/biosphere-water-modelling/lp
jml/key-publications#section-0
GMD editors, Christoph Müller (eds.) (2020): The Lund–Potsdam–Jena managed Land (LPJmL)
dynamic global vegetation, hydrology and crop model – developments, evaluations anddocumentation.
Specialissue
ofGeoscientific
Model
Development,
https://gmd.copernicus.org/articles/special_issue1028.html

71Annex 2: Indicators used for the Global Commons domains
GlobalCommons

Key Indicator

Target2030

Target
2050

Units

Target source

Climate system GHG Emissions

37

11 Gt
Defined by our own 1.5°C-compatible pathway
CO2eq/y (SSP2-Tall)r

Cryosphere/Cli
mate

Global Mean
Temperaturechange1.5

1.5 °CParis Agreement

Ocean

Aragonitesaturation rate

2.8

2.8 -

Steffen et al. 2015: 80% of pre-industrial valueof approximately 3.5

Ozone

Equivalent
Effective
Stratospheric
Chlorine (EESC)

2000

2000 ppt

1980 value, before substantial ozone depletion(Newman et al. 2007)

4300

4300 Mha

van Vuuren et al. (2021) target for 2050: 75%
of forested land as % of original forest cover.
Potential forest cover (without woodlands)
taken from the Global Map of Potential Forest
Cover. World Resources Institute (Potapov etal. 2021).

Land Biosphere Forest coverLand Biosphere Yearly naturalforest loss (net)00 Mha/yr van Vuuren et al. (2021) target for 2030: No
further primary forest loss

Land Biosphere Consumptive
agricultural
water use

1980

1980 km3/yr

Land Biosphere Human-induced
N fixation

90

90 Mt N/yr From Soergel et al. (2021). Proxy for nitrogen
losses to the environment, representing adriver of ecosystem degradation Fixation as anindicator follows van Vuuren et al. (2021).
Quantitative target: adopted from the
EAT-Lancet Commission (Willett et al. 2019).

Land Biosphere Biodiversity
Intactness Index

0.8

0.8 -

72

Central estimate from Springmann et al.
(2018): 1980 (780-3190) km^3

From Soergel et al. (2021). Adapted from van
Vuuren et al. (2021) (“no further
degradation”), which we translate into a
numerical value of 0.8 based on MAgPIE
results

Annex 3: Assumptions and interventions used to implement the system transformations in
REMIND-MAgPIE
1. The Energy Systems Transformation (Tene)
Intervention

Description of setting in models

Power
Decarbonisation of power generation In the power sector, even low CO2-prices, consistent with the Paris
Agreement only if all other transformations are also achieved, issufficient to decarbonise the sector by around 2060.
Also includes direct air capture (DAC) as an option to abate leftover
emissions from all sectors.
Decrease of battery storage costs

Learning for battery storage is considered by default in the model as a
response to the CO2 price.

Improvement of energy efficiency

Energy efficiency (and thus demand) is closely correlated to theCO2-price: An increasing CO2-price triggers energy efficiency
improvement in all sectors.

Transport
Improve transport infrastructure
Preference changes and infrastructure availability drive higher
Provide alternatives to car and plane
adoption of public, shared and non-motorized transport. In
transportation, shifts in preferences
conjunction with all other interventions (including GHG pricing) the
share of the total distance travelled in trains and non-motorized
Foster higher adoption of public,
shared and non-motorized transport modes roughly doubles by 2050.
Increased preference for battery Increased preference for battery electric vehicles (BEVs). The
electric vehicles
expansion of charging infrastructure is represented indirectly by
reducing inconvenience costs as demand for BEvs increase. As a result,almost all Light-Duty Vehicles (LDV) and most trucks are Battery
electric vehicles (BEV) in 2050 in a current policy scenario. BEV
adoption also responds to changes in fuel/energy prices driven byother interventions.
Use of synthetic gases and liquids asalternative, low-emission fuels.

Increase of use of synthetic gases and liquids as alternative,
low-emission fuels.
Include CCU as an option for the production of synthetic fuels.

2. The Land Systems Transformation (Tland)
Land-based solutions (LNDlbs)
Intervention

Description of setting in models

Forests
CO2 pricing policy on land-use change Inclusion of CO2 emissions from conversion of natural land (i.e. forests
and non-forest natural vegetation) into the GHG pricing scheme
economically dis-incentivises expansion of cropland and othermanaged land73

Peatland protection

Inclusion of GHG emissions from degraded peatlands into the GHG
pricing scheme dis-incentivises further degradation of intact
peatlands. (for more information on peatland protection in MAgPIE
see Humpenoeder et al. 2020)

Protection of biodiversity hotspots

The land protection scheme covers all natural landscapes within areasthat were classified by Conservation International (CI) as biodiversity
hotspots (high prevalence of endemic species, whose native habitat
has already been lost by 70%). (for more information on theprotection of biodiversity hotspots in MAgPIE see Kreidenweis et al.
2018)

Afforestation

The GHG pricing scheme incentivises afforestation as a land-based
mitigation measure, which is restricted to the tropics due to albedo
effects. Moreover, afforestation is confined to a global maximum of
500 Mha and the application of native species, motivated by broader
sustainability considerations.

Restoration of peatlands

Rewetting of drained peatland is considered as a land-based
mitigation measure and incentivised by GHG pricing, where the GHG
emission reduction between the degraded and rewetted state isrewarded. (for more information on peatland restoration in MAgPIE
see Humpenoeder et al. 2020)

Protection of forests from shifting
agriculture

Damage from shifting agriculture to natural forests is assumed to beprevented from 2030 onwards.

Food
Investments in research anddevelopment in the agricultural
sectorResource scarcity and demand pressure increase the incentives toinvest into agricultural research and development (R&D) that foster
crop yield gains. Land protection and GHG pricing policies canincrease land scarcity, thereby also strengthening efforts to improve
crop yields and increase crop production without land expansion. (formore information on R&D investments in MAgPIE see Dietrich et al.
2014)

Sustainable food demand (LNDfood)
Food
Reduction of food waste

Regional per-capita food waste is reduced to a maximum of 50% thecurrently observed levels in high income regions until 2050.

Dietary transition towards the
EAT-Lancet diet and daily per-capita
kcal consumption consistent with ahealthy body weight

Diets change gradually towards healthy dietary patterns, which arecharacterized by a shift from resource-intensive animal-source foods
to plant-based products associated with lower environmental impacts
and by an increasing share of healthy foods like fruits, vegetables, andnuts, as proposed by the EAT–Lancet Commission. (see Willett et al.
2019)
Total daily per-capita kcal consumption of different population
sub-groups converges to levels consistent with a healthy body weight.

Ressource-efficient production systems (LNDreseff)
74

Food
Intensification of livestock production
systems

Strong increase of livestock productivity results in improved feed
efficiencies in five animal food systems (beef cattle, dairy cattle, pigs,
broilers and laying hens). (for more information on the livestock
sector in MAgPIE see Weindl et al. 2017a, b)

More efficient animal waste
management systems

Improved management of manure leads to a lower share of nutrientsthat are lost due to volatilization and denitrification, a higher share ofrecycled nutrients, and lower non-CO2 emissions. (see Bodirsky et al.
2012)

Improved nitrogen use efficiency

Efficient fertilization and associated increased soil nitrogen uptake
efficiency, converging to 75% by 2050, reduces excessive nitrogenfrom agricultural systems and related negative impacts on terrestrial
and aquatic ecosystems as well as N2O emissions. (for more
information on efficient fertilization as a measure to mitigate
nitrogen pollution in MAgPIE see Birdirsky et al. 2014)

GHG policy pricing agricultural non-CO2 A GHG pricing scheme targeting agricultural non-CO2 emissions
emissions
economically incentivises investments into technical measures toreduce N20 and CH4 emissions from agriculture, e.g. feed additives.
(for more information on the abatement of agricultural non-CO2
emissions in MAgPIE see Stevanović et al. 2016)
Phase out 1st generation bioenergy

First generation bioenergy production is gradually phased out
between 2020 and 2050 (for more information on the default
scenario trajectory for first generation bioenergy (based on currently
established and planned bioenergy policies), on which the phase-out
is applied see Lotze-Campen et al. 2014).

Freshwater Management
Protection of environmental flow
requirements

The water protection scheme reserves a certain fraction of locallyavailable freshwater, which is needed to preserve
freshwater-dependent ecosystems. The high- and low-flow
requirements on which the parametrization of the protection scheme
is based are selected to maintain freshwater-dependent ecosystems
in an at least “fair” condition (Smakhtin, Revenga, and Döll 2004). (formore information on the protection of environmental flow
requirements in MAgPIE see Bonsch et al. 2015).

Improved nitrogen use efficiency

See description above.
Measures to mitigate excessive nitrogen from agricultural systems
reduce the influx of nitrogen into rivers and lakes, a driver of waterpollution, and improve water quality.

Protection of environmental flow
requirements

See description above.

Increase in irrigation efficiency

Water management in agriculture can be improved by increasing theratio of withdrawn water that reaches the plants, by reducing losses
in conveyance systems and from application to the field. (for more
information on irrigation efficiency in MAgPIE see Schmitz et al.
2013).

75

3. The Sustainable Production and Consumption Transformation (Tpc)
Intervention

Description of setting in models

Increasing material efficiency inproductionMore efficient use of materials in industry, less waste in productionand extended lifetimes of products lead to reductions in totalmaterial demand for steel and cement by 77% and 20% respectively.
These reductions are gradually achieved between 2020 and 2050.

Change in consumption patterns

Changes in consumption patterns, including the move towards amore sharing and circular economy, lead to reductions in totalmaterial demand for steel and chemicals (which includes plastics) by
10% and 32% respectively. These reductions are gradually achieved
between 2020 and 2050.

76