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Suggested citation
Christensen, J. and Olhoff, A. (2019). Lessons from a
decade of emissions gap assessments. United Nations
Environment Programme, Nairobi.
https://www.unenvironment.org/resources/
emissions-gap-report-10-year-summary

1
Lessons from a decade of emissions gap assessments

This publication has been prepared by the scientificeditors of the UN Environment Emissions Gap Reports:
John Christensen (UNEP DTU Partnership) and Anne
Olhoff (UNEP DTU Partnership).
UN Environment warmly thanks all the authors, themembers of the steering committee and the reviewers of
the emissions gap assessments over the past 10 years fortheir invaluable contributions.
This year, UN Environment will publish the tenthedition of the annual Emissions Gap Report. To mark the
10-year anniversary and as a contribution to the United
Nations Secretary-General's Climate Action Summit, thispublication revisits the gap rationale and how it has evolved,
comparing the expectations following the Copenhagen
Accord with the reality 10 years later. The findings are1

sobering. Despite a decade of increasing political andsocietal focus on climate change and the milestone Paris
Agreement, global greenhouse gas (GHG) emissions havenot been curbed, and the emissions gap is larger than ever.
The challenges for the United Nations Secretary-General’s
Climate Action Summit and for international climate change
negotiations in 2019 are clear. Unless mitigation ambition
and action increase substantially and immediately in theform of new or updated nationally determined contributions(NDCs) by 2020 and are reflected in ambitious long-term
GHG development strategies, exceeding the 1.5°C goal
can no longer be avoided, and achieving the well-below
2°C temperature goal becomes increasingly challenging.
These and other key lessons emerging from a decadeof Emissions Gap Reports are summarized under the 10
headings of this publication.

The Emissions Gap Report – the annual gaugeof the disconnect between where we are andwhere we need to be

The Copenhagen Accord of 2009 and the Cancun
Pledges of 2010 – the origin of the 2020 emissions gap
assessments
The Copenhagen Accord declared that “deep cuts” inglobal emissions were required “so as to hold the increase inglobal temperature below 2 degrees Celsius” and called foran assessment that would consider strengthening the longterm goal, including in relation to “temperature rises of 1.5
degrees Celsius”. Since December 2009, 140 countries haveendorsed the Copenhagen Accord. Of these, 85 countries
have pledged to reduce their emissions or constrain their
growth up to 2020.
The pledges and the temperature targets referred toin the Copenhagen Accord were formalized by the 2010
Cancun Agreements and gave rise to a central question: will
there be a gap in 2020 between emissions expected underfull implementation of pledges and the level consistent withthe 2°C target? This was the central question addressed in
the Emissions Gap Reports from 2010 to 2014 (UNEP 2010;
UNEP 2011; UNEP 2012; UNEP 2013; UNEP 2014).

Some of the Cancun Pledges for 2020 were unconditional,
while others were conditional on action by others or support
received, and their GHG emission implications furthermore
depended on whether a strict or lenient interpretation of
accounting rules was applied. Consequently, the Emissions Gap
Reports operated with four pledge cases for 2020 (Figure 1).
To estimate the 2020 emissions gap, the emissions under
the pledge cases were compared with a median estimate ofglobal emissions in 2020 consistent with a pathway to 2°C in
2100 (with at least 66 per cent chance). This approach has been
applied consistently over all the years, with a shift to 2030 as
the focal year as it became the target for the Paris Agreement.
Over the 2010–2014 period, the gap estimates for 2020
ranged from a low of 5 GtCO � e according to the most ambitious
pledges and measured under strict accounting rules (UNEP2010) to a high of 13 GtCO � e in 2020 according to the least
ambitious pledges and more lenient accounting rules (UNEP2012). As pledges and accounting approaches became clearer,
the gap estimate converged towards between 8 and 10 GtCO � e(UNEP 2014).

2
The Paris Agreement – strengthened temperature goals
and a shift to the 2030 emissions gap
The Paris Agreement, adopted by 195 countries at
Conference of the Parties (COP) 21 in December 2015,
represents a major step forward on global climate governance.
It sets out a global action plan to put the world on track to
avoid dangerous climate change by limiting global warming
to well below 2°C and pursuing efforts to limit it to 1.5°C, thetwo formal temperature goals of the agreement.
Nationally determined contributions (NDCs) are at theheart of the Paris Agreement and the approach adopted
in favour of its long-term goals. NDCs represent national
climate plans that embody efforts by each country to
reduce national emissions and adapt to the impacts ofclimate change. At the time of writing, 184 Parties havecommunicated their first NDCs.
Acknowledging that a voluntary bottom-up politicalprocess is unlikely to be very ambitious from the outset, theParis Agreement is designed with a five-year review and new
submission cycle, making it possible to collectively ramp up
ambitions over time.
With the Paris Agreement, the focus of the gap
assessment shifted from 2020 to 2030 as the new target
year, and started to include the 1.5°C limit of the agreement,
as shown in Figure 2.
In line with the 2020 emissions gap, the 2030 emissions
gap is estimated as the difference between projected global
emissions in 2030 under full implementation of conditional
and unconditional NDCs respectively and the emissions
levels that scientific projections indicate are consistent withlimiting global temperature increase in 2100 to below 2°C
and 1.5°C respectively.

Figure 1 — The emissions gap in 2020

Source: UNEP (2011)

Figure 2 — The emissions gap in 2030

No policy baseline
Current policy scenario
Unconditional NDC scenario
Conditional
NDC scenario

Pink area shows
pathways limiting global
temperature increase to
below 2°C by 2100 with
about 66% chance
Purple area shows pathways
limiting global temperature
increase to below 1.5°C by
2100 with about 66% chance

Source: UNEP (2018), Figure 3.1.

Remaining gap
to stay within
2°C limit
level

limit

level

3

2

A decade lost – essentially no change in global
emissions trend

Despite progress on climate policy in many countries,
global GHG emissions continue to grow and show no signsof peaking (Figure 3). Global GHG emissions grew at an
average of 1.6 per cent per year during the period from 2008
to 2017, reaching a record 53.5 GtCO � e in 2017, including
emissions from land-use change. Preliminary findings fromthe Emissions Gap Report 2019 indicate that global GHG
emissions continued to grow in 2018, breaking the 2017
record. Countries with declining emissions have so far been
unable to offset the growth in emissions in other countries
and in sectors not covered by national accounting, such asaviation and shipping.

The current level of global GHG emissions is by now
almost exactly at the level of emissions projected for 2020
under the business-as-usual, or no-policy, scenarios used in
the Emissions Gap Reports (see Figures 1 and 2), which are
based on the assumption that no new climate policies are
put into place from 2005 onwards. In other words, essentiallythere has been no real change in the global emissions
pathway in the last decade. The effects of climate policies
have been too small to offset the impact of key drivers ofemissions such as economic growth and population growth.

Figure 3 — Global greenhouse gas emissions per type of gas (left) and Top greenhouse gas emitters, excluding land-use
change emissions due to lack of reliable data (right)

Source: UNEP (2018), Figure 2.3.

4This rather bleak fact hides many nuances in termsof, for example, policy progress in individual countries anddeclines in energy and carbon intensities. The Emissions
Gap Reports assess that collectively G20 members areon track to achieve the mid-level of the Cancun Pledges,
although some G20 members are projected to miss theirpledges, or there is uncertainty as to whether they willachieve them.
Acknowledging the importance of achieving of the
Cancun Pledges, the fact remains that at the global scale
we have failed to bridge or even narrow the 2020 emissions
gap, as assessed in the Emissions Gap Reports from 2010
to 2014.
The Emissions Gap Repor ts have consistently
emphasized the importance of enhanced pre-2020 action andpledges and warned that unless urgent action is taken, there
will be a number of consequences, including (UNEP 2016):●●

Significantly higher rates of global emission reductions
are required in the medium- and long-term to meet thewell-below 2°C target. The order of magnitude of these
rates has no historic precedent.

3●●

The ‘solution space’ and options available to society
to achieve stringent emission reductions is reduced.

●●

Greater lock-in of carbon- and energy-intensive
infrastructure in the energy system and society, as awhole, which will simultaneously be a disincentive forthe short-term learning and technology developmentthat is essential in the long-term.

●●

Greater dependence on negative emissions
technologies in the medium term – technologies thatso far are unproven on a larger scale.

●●

Increased costs of mitigation and adaptation in themedium- and long-term, and greater risks of economic
disruption.

Importantly, delaying action is associated with greaterrisks of failing to meet the well-below 2°C target and isincompatible with meeting a 1.5°C target. The implication
is clear: if the Paris goals are to be kept viable, the world
cannot afford to lose another decade.

The emissions gap is larger than everConcerns about the current level of both ambition andaction are amplified in the 2018 report and the forthcoming2019 report. As shown in Figure 2, the 2018 report estimatesthe emissions gap in 2030 between emission levels with full
implementation of conditional NDCs and levels consistent
with least-cost pathways to the 2°C target to be 13 GtCO � e.
If only the unconditional NDCs are implemented, the gap
increases to 15 GtCO � e.
The gap in the case of the 1.5°C target is 29 GtCO �e and
32 GtCO � e respectively. The gap numbers have increased
compared with 2017, mainly as a result of the more detailed
and diverse literature on 1.5°C and 2°C pathways prepared
for the Intergovernmental Panel on Climate Change (IPCC)
Special Report on global warming of 1.5°C . This literature
made it possible to assess the gap compared to pathways
associated with a “likely chance” (at least 66 per cent) of
meeting the 1.5°C target, the same probability used for the
2°C gap assessment. Due to the lack of available studies
that could achieve 1.5°C with a likely chance, earlier reports
only considered the gap associated with a “medium chance”(50 to 66 per cent) of limiting temperature increase to 1.5°C
in 2100.

Updated analysis for the for thcoming 2019
Emissions Gap Report reiterates that progress on national
commitments under the Paris Agreement is limited and thatthe current pace of national action is hugely insufficient forachieving the Paris Agreement long-term temperature goal,and even for achieving the emissions reductions implied by
the current NDCs. Increased emissions and lagging actionmeans that the gap numbers in the 2019 report will be larger
than ever.
Considering the entire decade of Emissions Gap
Reports, three main factors contribute to the growing
emissions gap. First, the failure to bridge the original 2020
emissions gap has led to a larger 2030 gap. Whereas the2020 gap for 2°C was 8 to 10 GtCO � e in the 2014 report, the2030 gap is in the order of 13 to 15 GtCO � e. In other words,
the 2030 gap is about 50 per cent larger than the 2020 gap.
Second, the strengthened temperature targets of the Paris
Agreement of well below 2°C and 1.5°C imply an increase in
the emissions reductions needed by 2030. Third, over timeand as scientific knowledge has improved, the pathwaysfor especially the 1.5°C target have become more stringent.
Altogether, ambition and action over the past decade have
simply been inadequate, so action now needs to be fasterand more transformational.

5

4

The global challenge – the ambition level of current
NDCs needs to be tripled to get on track to 2°C andincreased fivefold to align with 1.5°C

The Emissions Gap Reports show that nations must
triple the level of ambition reflected in their current NDCs to
get on track towards limiting warming to below 2°C, whileat least a fivefold increase is needed to align global climate
action and emissions with limiting warming to 1.5°C by theend of this century (see also Figure 2). For this to be realistic,
new and enhanced NDCs need to be agreed by 2020 and theimplementation of existing actions accelerated.
The defining challenge for the United Nations
Secretary-General's Climate Action Summit in 2019 andfor the United Nations Framework Convention on Climate
Change (UNFCCC) negotiations over the coming year is tobring about this giant leap in ambition and to accelerateaction. As Figure 4 shows, enhanced mitigation ambition
can take many forms and options must be pursued in all
categories and by all countries to meet the challenge. The
year 2020 will be defining. Given the time lag between
developing policies and achieving emission reductions,enhanced ambition of NDCs cannot wait until the global
stocktake planned for 2023.

The Emissions Gap Repor ts conclude that acontinuation of current policies would lead to a global
mean temperature rise of between 3.4°C and 3.7°C by 2100
relative to pre-industrial levels, and continuing thereafter(UNEP 2016). Implementing the current unconditional NDCs,
and assuming that climate action continues consistently
throughout the twenty-first century, would lead to a global
mean temperature rise of between 2.9°C and 3.4°C by 2100
relative to pre-industrial levels, and continuing thereafter.
Implementation of the conditional NDCs would reducethese estimates by 0.2°C in 2100 (UNEP 2016; UNEP 2017;
UNEP 2018). These numbers are currently being updated
for the forthcoming Emissions Gap Report, and will likely
become even more dramatic.

Figure 4 — Options for enhancing ambition of the NDCs

implementation
sectoralIncrease

Increase

sectoralpolicies
policies

sectoral

DeclareDeclaremodalities

Source: UNEP (2018), Figure 4.1.

sectoralsectoralpolicies

long-term

6

5

The gap can still be bridged, but unprecedented
and immediate action is required

To assess whether the emissions gap can be bridged,
the Emissions Gap Reports have regularly assessed sectoral
emission reduction potentials. The 2017 report provided
a detailed updated systematic assessment of sectoral
mitigation options in 2030, which shows that the emissions
gap can be bridged before 2030 if countries quickly adopt
proven and cost-effective technologies and management
practices. A substantial part of the economic and technicalpotential can be realized through scaling up and replicating
existing, well-proven policies that simultaneously contributeto key Sustainable Development Goals (SDGs).
The 2017 assessment showed that by considering only
proven technologies and adopting relatively precautionary
assumptions, emissions could be reduced by 33 GtCO � e per
year by 2030 (uncertainty range of 30–36 GtCO � e), which
is sufficient to get on track to well below 2°C and 1.5°C.
This 'basic' potential is illustrated in Figure 5. Remarkably,a large part of this potential is available in just six areas:
solar energy, wind energy, efficient appliances, efficientpassenger cars, afforestation and stopping deforestation.
These six areas present a combined potential of up to 21
GtCO � e per year by 2030, which is more than sufficient to
get on a pathway to well below 2°C.
If areas where estimates of potentials are relatively
new, and the feasibility of realizing these in 2030 is more
uncertain, are also considered, the total emission reduction
potential is 38 GtCO � e per year (uncertainty range of 35–41
GtCO � e).
The underlying assumption is that all countries will act
quickly and implement the most cost-effective measuresin their national contexts. This is evidently a very idealistic
assumption, but it underlines the fact that the policies andtechnologies needed to bridge the gap are readily available
and at limited costs. While new innovation will be needed
for full decarbonization, there is no excuse for inaction now.

Figure 5 — Total emission reduction basic potentials compared to the current policy scenario for 2030

Source: UNEP (2017), Figure 4.1.

7
Only a fraction of this potential is captured in thecurrent NDCs, so the potential for enhanced ambition andaction is huge. As stated above, this potential is sufficient
to close the 2030 gap, even for the ambitious 1.5°C goal.
The 2018 Emissions Gap Report showed that major
gaps in coverage and stringency of domestic policies
remain, including among key G20 members. These findings
are reinforced in the pre-release chapter of the forthcoming
Emissions Gap Report on opportunities for enhancing
mitigation ambition and action among G20 members inparticular. For example, in the areas of fossil-fuel subsidy
reduction, material efficiency measures in industry, oil andgas methane, support schemes for renewables, heating
and cooling systems, emission standards for heavy-duty
vehicles, and e-mobility programmes, and even in areas
where policy coverage is high, stringency can be improved.

Despite the huge potential of carbon pricing to reduce
GHG emissions, it is still only just emerging in many
countries and is generally not applied at a sufficient levelto facilitate a real shift towards low-carbon societies. Even
when considering energy-specific taxes together with
explicit carbon pricing policies, half of the emissions fromfossil fuels are not priced at all, and only 10 per cent of global
emissions from fossil fuels are estimated to be priced at
a level consistent with limiting global warming to 2°C. If
all fossil-fuel subsidies were phased out, it would lead toa reduction of global carbon emissions of up to about 10
per cent by 2030. In this and other areas, ensuring political
viability and handling distributional impacts of the transition
to development paths in line with the Paris Agreement isoften key, as illustrated by Figure 6.

Figure 6 — Key issues for making fiscal reforms politically viable (upper part) and solutions and measures to address them(lower part)

Investments
structural

ClimateSource: UNEP (2018), Figure 6.3.

low-

8
Reducing short-lived climate pollutants (SLCPs) is
another area that is attracting attention. These agents
have a relatively short lifetime in the atmosphere – froma few days to a few decades – but are potent GHGs witha significant short-term warming influence on the climate.
The main SLCPs are black carbon, methane, troposphericozone and some hydrofluorocarbons (HFCs). Reducing
these pollutants will limit the rate of short-term warming
and, when sustained and combined with carbon dioxide(CO �) reductions, will help limit long-term warming, which is
the ultimate aim of closing the emissions gap (UNEP 2017).
One significant development is the phasedown of
HFC use and associated emissions as a result of the Kigali
Amendment to the Montreal Protocol, which could reduce
global hydrofluorocarbon emissions by 0.7 GtCO � e per
year by 2030, and by up to 2.7 GtCO � e per year by 2050.
Additional indirect CO � mitigation is likely through parallel
improvements in the energy efficiency of refrigeration and6

air-conditioning appliances and equipment. Previous phaseouts under the Montreal Protocol have catalysed significant
improvements in the energy efficiency of appliances – by
up to 30 per cent in some subsectors. UN Environment iscurrently undertaking a separate scientific assessment ofthese effects.
It is worth noting that in its 2018 assessment, the
Scientific Assessment Panel for the Montreal Protocol
concluded that “The Kigali Amendment is projected toreduce future global average warming in 2100 due tohydrofluorocarbons (HFCs) from a baseline of 0.3–0.5°C toless than 0.1°C. The magnitude of the avoided temperature
increase due to the provisions of the Kigali Amendment(0.2 to 0.4°C) is substantial in the context of the 2015 Paris
Agreement” (World Meteorological Organization 2018).
Some of the other key action areas covered inrecent Emissions Gap Reports are highlighted under thesubsequent headlines.

Decarbonizing energy supply and transport is key fortransformational change

CO � emissions from fossil-fuel use in the energy andindustry sectors dominate total GHG emissions. Following aperiod of stabilization from 2014 to 2016, emissions started
to rise again in 2017 and 2018. At the same time, energy
needs are projected to grow by approximately 30 per centby 2040. This increasing demand is stimulated by economic
growth and the accompanying trends of urbanization,industrialization, infrastructure growth, and a growing
global middle class. As the challenge for the energy sector
is therefore immense, transforming the way in which energy
is produced and consumed will be key to reaching the Paris
Agreement goals.
The forthcoming Emissions Gap Report examines
key elements of the required energy transformation, which
combined with findings from previous reports stress theurgency of accelerating energy efficiency across the board
and of rapidly expanding renewable energy supply and use.

Enhanced energy efficiency is required across the board
with a strong focus on heating and cooling, appliances andlighting, industrial processes and motors, and transport.
Many policy options exist in key sectors and havebeen documented in previous Emissions Gap Reports. For
example, the 2016 Emissions Gap Report highlighted asmall number of successful policies that have already been
implemented or are under implementation in many countries
that can be rapidly replicated and scaled up (Figure 7).
The transport sector can be treated either as a subset
of energy consumption or separately as an important
individual sector for mitigation interventions. There is anincreasing focus on electrification as a major mitigation
option in transport. Such a transition would bring significant
local air pollution benefits, and in the transport sector inparticular there is a need for an integrated approach.

9
Almost all NDCs include mitigation in the energy sector
as a key area and around 75 per cent include actions ontransport focusing on three concepts: (1) To avoid andreduce the need for motorized transportation, (2) To shift
to more environmentally friendly modes of transportation,and (3) To improve the energy efficiency of transport modes.

Figure 8 — Cumulative solar PV installations compared toforecasts from various International Energy Agency (IEA)
World Energy Outlooks

The transition requires rapid expansion of renewable electricity supply, establishment of smarter and more flexible
electricity grids, and huge increases in the numbers of
products and processes that run on electricity in buildings, transport and industry.
The renewables expansion has already become
increasingly market driven. Stable and conducive policies
and regulatory frameworks are, however, importantpreconditions along with access to the necessary private
sector finance. Overall capacity additions in 2018 werearound 50 gigawatts for wind power and more than 100
gigawatts for solar photovoltaic (PV) power. For the seventh
successive year, the net additional power generation
capacity of renewable sources exceeded that of nonrenewable sources. Growth rates in renewable power haveaveraged 8–9 per cent per year since 2010. Renewableenergy investment continues to increase, although it isslightly down from 2017 (UNEP forthcoming). This trend
over the last decade is encouraging, but it will need to beaccelerated even further, as described above and illustrated
in Figure 8.

Source: UNEP (2018), Figure 7.2.a.

Figure 7 — Examples of proven sectoral energy efficiency policies

Buildings• Energy codes• Information andenergy performancecertiﬁcation• Highly energy
efﬁcient buildings

Source: UNEP (2016), Figure ES.7.

Industry• Energy management,
ISO 50001 andenergy performancemonitoring• Energy performancestandards forindustrial equipment• Energy service
companies

Transport• Vehicle fuel economy
standards• Electric mobility forpassenger transport• Sustainable logistics /freight transportation

10

7

Phasing out coal is indispensable, but requires
a balanced transition

At the global scale, the stock of coal-fired power plants
is still increasing, as are emissions from coal. The existing
stocks, in combination with what is currently planned andbeing built (assuming standard lifetimes and usage rates)
alone account for a significant share of the available carbon
budget for a 2°C target, and would plausibly make a 1.5°C
target infeasible, as illustrated in Figure 9. Facilitating atransition away from coal for power production will therefore
be essential to successful global mitigation efforts. Avoiding
further lock-in through new coal-fired power plants istherefore a major and urgent requirement, followed by agradual phasing out of existing coal plants.

While coal is widely used, only around 10 or 11 large
countries have very significant coal emissions. For allthese countries, a transition away from coal presents
a major political and economic challenge that will taketime. Removing domestic subsidies and including pricingof externalities will be important, with the latter helping
generate revenue to address the societal challenges atransition will encounter. This will include addressing
impacts on affected workers and communities, as well as
the coal owners and industry, balancing energy prices fordifferent social groups and energy-intensive industries, tomention a few (see also Figure 6).

Figure 9 — Emissions committed to the atmosphere from coal-fired power plants (existing, under construction and planned)
and other economic sectors, by region

2°C budget with
>66% probability
1150-1250 GtCO�
from 2016

1.5°C budget with>50% probability
560-660 GtCO�
from 2016

Source: Based on UNEP (2017), Figure 5.1.

11

8

Nature-based solutions can make a large contribution
and are currently the main option for CO� removal

The Climate Action Summit uses the term ‘naturebased solutions’ as the convening theme for a broad set ofissues related to the enhanced used of natural systems for
improving mitigation and adaptation to climate change. The
main categories include:

Best practice policies to curb deforestation werereviewed in the Emission Gap Reports in both 2012 and 2015and highlighted four distinct policy categories that haveeconomic potential to mitigate around 5 GtCO � e annuallyby 2030 according to the 2017 Emissions Gap Report:●●

Forests and other terrestrial ecosystems●●

Establishing new protected areas.

●●

Agriculture and food systems●●●●

Marine and coastal ecosystems

Using command-and-control measures (enacting,enforcing and monitoring of regulations on forest
conversion, may include investment in existing
protected areas to prevent incursion).

●●

Using economic instruments (taxes, subsidies,
payments for ecosystem services).

●●

Creating policies affecting drivers and contexts thatcurrently promote deforestation (sectoral policies,
institutional frameworks, governance structures andagricultural subsidy reform).

Not all aspects of nature-based solutions have been
covered in the Emissions Gap Reports. However, mitigation
potentials and options in forestry, including REDD+, wereassessed in the 2012, 2015 and 2017 reports, agriculture
options in the 2013 and 2017 reports, and nature-based
CO � removal options in the 2017 report. The Emission
Gap Report findings are aligned with the information in the
recently released IPCC Special Report on Climate Change
and Land and the fifth assessment report of the IPCC.
Most mitigation options are quite well known, but often
difficult to implement in practice due to challenges related
to limited access to financing, poverty issues, institutions,
ecological issues, and barriers concerning technologicaldevelopment, diffusion and transfer.

9Non-State and subnational actors are essential, but thecurrent mitigation impacts are still limited and poorly
documented

Non-State and subnational action plays an importantrole in delivering NDCs. Since 2015, the Emissions Gap
Reports have included assessments of the role of suchaction and the 2018 report included a special focus on nonState and subnational actors. The 2018 report documents
the rapid increase in the number of actors participating inclimate action: more than 7,000 cities from 133 countries
and 245 regions from 42 countries, along with more than
6,000 companies with at least US$36 trillion in revenue,
have pledged mitigation action.
Commitments cover large parts of the economy andare gradually expanding in terms of regional coverage. Manyof the actors are engaging in ‘international cooperative

initiatives’, which are characterized by multi-country andmulti-actor engagement. The numbers are impressive, butthere is still huge potential for expansion. Based on available
data, less than 20 per cent of the world population isrepresented in current national and international initiatives,and many more of the over 500,000 publicly traded
companies worldwide still can, and must, act.
Assessing the emission reduction potential from nonState and subnational action is challenging and must take into
account overlaps with national action. The Emissions Gap
Reports find that the potential could ultimately be significant,allowing countries to raise their ambition, but the current
impacts are limited and poorly documented (Figure 10).

12Figure 10 — The range of estimated potential emission reductions in various non-State and subnational action studies

Source: UNEP (2018), Figure 5.4.

10

Innovation and new solutions are needed for long-term
carbon neutrality

Combining innovation in the use of existing technologies
and in behaviour with the promotion of investment in newtechnologies and market creation has the potential toradically transform societies and reduce their GHG emissions.
However, it will not happen by itself. Five principles are likely to
be key in the design of policies and programmes to accelerate
low-carbon innovation (UNEP 2018):

3.

Green policies must set a direction for the whole
economy, not for each sector separately.

4.

Mission-oriented innovation is useful for stimulating
investment and innovation across different parts of theeconomy to reach concrete, target-specific goals by aspecific date.

1.

Public organizations must be willing to take on thehigh, early-stage risk that private organizations shy
away from.

5.

2.

At the mid-stage of the innovation chain, publicorganizations must be able to nurture feedback effects
among different parts of the innovation landscape andhelp de-risk private investment in commercial-scale
projects.

Policy instruments need to be structured tomobilize actors through bottom-up exploration andparticipation. All these policies benefit from a longterm design horizon that creates certainty for private
finance to be crowded in.

13CO� removal is one of many areas where innovationand new solutions are needed. Most of the global modellingscenarios that analyse different pathways to achieving theParis Agreement goals of 1.5°C or well below 2°C include
elements of ‘negative emissions solutions’, that is, options
that actively reduce CO� in the atmosphere. In the 2017
Emissions Gap Report, the various options for CO� removal
were therefore assessed. CO� removal and the deploymentof negative emissions approaches must be employed inaddition to other mitigation options. In other words, CO�removal is concerned with the management of overshoot,in the event that all relevant mitigation options have been
pursued.
Figure 11 provides an overview of the various CO �
removal options and strategies. Natural removal options
have already been mentioned as part of the nature-based
solutions and currently constitute the main and most costeffective options for CO � removal. The combined options
focus on increased use of bioenergy, especially for power
production, combined with Carbon Capture and Storage(CCS). Studies indicate a significant mitigation potential
but there are many unresolved issues around the land andwater resources required for large-scale biomass for energy
production and currently CCS is too costly for large-scale
deployment.

Human-made technologies to remove CO � from theair have been in use for many years, mostly in submarine,
aerospace and medical applications. Only recently havethese technologies been considered as global-scale carbon
removal agents. They offer specific benefits in that they usevery little land or water, they do not emit non-CO � GHGs andthey have very high levels of certainty regarding the flux
and long-term fate of the CO � removed. Some approaches
also produce materials that can be used commercially, forexample, cements and aggregates.
However, many approaches are very expensive and may
have numerous, as yet unknown, side effects that may haverepercussions for societies. Most have not been deployed atscale and have a low level of technical readiness. Nonetheless,increased investment in developing these options could, overtime, change the situation. Precaution is recommended, andpros and cons need to be assessed, before any full-scale
deployment could happen. The United Nations may have arole to play in ensuring an overarching intergovernmental
policy approach that can help ensure no one is left behind, if
such technologies are to be deployed widely.

Figure 11 — Major strategies for negative emission technologies→→→

Source: UNEP (2017), Figure 7.1.

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14
Looking ahead – the next decade will be defining
While the past decade has been a lost opportunity
in terms of bending the global emissions curve, a large
number of positive policy and technology developments
have taken place, creating a solid foundation for enhancing
mitigation ambition and accelerating action. The scientificunderstanding of both the consequences of inadequate
action and the available options for rapid and cost-effective
emission reductions has also improved significantly.
Bending the emissions curve and bridging the emissions
gap, while presenting an unprecedented challenge, is still
possible. It will require the full utilization of all emission

reduction options and policies to support these, replicationand scale-up of current best practices, a shift in investments
to bring about the transformations and innovations neededin the longer term, and careful management of the interestsof the economic and societal sectors that might be affectedduring the transition to a zero-carbon and climate-resilient
future. It will require concerted climate action of all
stakeholders, at all levels and in all sectors.
The next decade will be defining – postponing ambition
and action is no longer an option, if we want the goals of theParis Agreement to remain within reach.

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UNEP (2011) Bridging the Emissions Gap.
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UNEP (2017) The Emissions Gap Report 2017.
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UNEP (2012) The Emissions Gap Report 2012.
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Nairobi: United Nations Environment Programme (UNEP).
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Nairobi: United Nations Environment Programme (UNEP).
Available at: unenvironment.org/emissionsgap

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