Global Warming of 1.5°C
Valérie Masson-Delmotte
Co-chair, IPCC Working Group I (Physical Science Basis)

valmasdel

The report in numbers

91 Authors from 40 Countries
133 Contributing authors
6000 Studies

1 113 Reviewers

42 001 Comments

Where are we?
Since pre-industrial times, human activities havecaused approximately 1.0°C of global warming.
• Already seeing consequences for people,
nature and livelihoods• At current rate, would reach 1.5°C between
around 2030 and 2050
• Past emissions alone do not commit theworld to 1.5°C
Ashley Cooper / Aurora Photos|Cumulative emissions of CO2 and future non-CO2 radiative forcing
determine the probability of limiting warming to 1.5°C

|Cumulative emissions of CO2 and future non-CO2 radiative forcing
determine the probability of limiting warming to 1.5°C

|Cumulative emissions of CO2 and future non-CO2 radiative forcing
determine the probability of limiting warming to 1.5°C

|Cumulative emissions of CO2 and future non-CO2 radiative forcing
determine the probability of limiting warming to 1.5°C

|Cumulative emissions of CO2 and future non-CO2 radiative forcing
determine the probability of limiting warming to 1.5°C

|Cumulative emissions of CO2 and future non-CO2 radiative forcing
determine the probability of limiting warming to 1.5°C

|Cumulative emissions of CO2 and future non-CO2 radiative forcing
determine the probability of limiting warming to 1.5°C

Faster immediate CO2
emission reductions limit
cumulative CO2 emissions

|

Cumulative emissions of CO2 and future non-CO2 radiative forcing
determine the probability of limiting warming to 1.5°C

Maximum temperature rise is determined bycumulative net CO2 emissions and net non-CO2
radiative forcing due to methane, nitrous oxide,aerosols and other anthropogenic forcing agents.

Spatial patterns of changes in annual mean temperature and precipitation
Global warming of 1.5°C

26 CMIP5 models; hatching : 66% model agreement

2°C

Spatial patterns of changes in extreme temperature and precipitation
Global warming of 1.5°C
Number of hot days(days)

Temperature ofhottest days (°C)

Temperature ofcoldest nights (°C)

Extremeprecipitation (%)

2°C

Emergence and intensity of regional climate change hot spots
Arctic summer sea-ice
 L maintained; 50% or higher risk to be ice free; VL to be ice free Habitat (polar bear, whales, seals, sea birds) : losses; losses; critical losses Arctic fisheries : benefits; benefits; benefits

Warming of 1.5°C or
less
Warming of 1.5ºC-2°C
Warming > 2°C

L, likely
VL, very likely
LC, low confidenceMC, medium confidenceHC, high confidenceEmergence and intensity of regional climate change hot spots
Arctic land regions
 Cold extreme: warm up to 4.5°C (HC); warm up to 8°C (HC); VL drastic warming Tundra : L biome shifts; L more shifts; drastic biome shift possible (LC) Permafrost : L 17-44% reduction; L larger (28-53%); potential for collapse (LC) Boreal forest : increased mortality at S. boundary (MC); further (MC); potential dieback (LC)

Warming of 1.5°C or lessWarming of 1.5ºC-2°C
Warming > 2°C

L, likely
VL, very likely
LC, low confidenceMC, medium confidenceHC, high confidenceEmergence and intensity of regional climate change hot spotsAlpine regions
 Biomes : L severe shift; L even more severe; L critical

Warming of 1.5°C or lessWarming of 1.5ºC-2°C
Warming > 2°C

L, likely
VL, very likely
LC, low confidenceMC, medium confidenceHC, high confidenceEmergence and intensity of regional climate change hot spots

Mediterranean Extreme drought: increase probability(MC); robust increase(MC); robust and large increase(MC) Runoff decrease: about 9% (MC); about 17% (MC); substantial reductions (MC) Water deficit: risk (MC); higher risks (MC); very high risks (MC)Warming of 1.5°C or lessWarming of 1.5ºC-2°C
Warming > 2°C

L, likely
VL, very likely
LC, low confidenceMC, medium confidenceHC, high confidenceEmergence and intensity of regional climate change hot spots

Tropics

 # hot days and nights, heatwaves: increases (HC); largest increase; oppressive, VL health impact
 Livestock heat stress : increased; onset of persistent (MC); L persistent Crop yields: risks; extensive risks (W. Africa, SE Asia, S. America); VL substantial reductions
 Rainforests : reduced biomass; larger reductions; reduced extent, potential forest dieback (MC)Warming of 1.5°C or lessWarming of 1.5ºC-2°C
Warming > 2°C

L, likely
VL, very likely
LC, low confidenceMC, medium confidenceHC, high confidenceEmergence and intensity of regional climate change hot spots

Southeast Asia  flooding related to sea-level rise: risks; higher risks (MC); substantial increases in risk
 Asian monsoon : LC; LC; L increase in precipitation intensity
 Heavy precipitation: increase; stronger increase (MC); substantial increase Crop yield reductions: -; one third decline in per capita (MC); substantial reduction

Warming of 1.5°C or lessWarming of 1.5ºC-2°C
Warming > 2°C

L, likely
VL, very likely
LC, low confidenceMC, medium confidenceHC, high confidenceEmergence and intensity of regional climate change hot spots
L, likely
VL, very likely
LC, low confidenceMC, medium confidenceHC, high confidence

Warming of 1.5°C or lessWarming of 1.5ºC-2°C
Warming > 2°C

West African and the Sahel Monsoon : uncertain ; uncertain ; strengthening (LC) Hot nights, longer, more frequent heat waves: L ; L further ; VL substantial   in maize and sorghum production: L, about 40%  suitable area; L larger ;major regional food insecurities (MC) Undernutrition risks : increased; higher; highEmergence and intensity of regional climate change hot spots
L, likely
VL, very likely
LC, low confidenceMC, medium confidenceHC, high confidence

Warming of 1.5°C or lessWarming of 1.5ºC-2°C
Warming > 2°C

Southern Africa
 Water availability: reductions (MC); larger reductions (MC); large reductions (MC)
 # of hot nights and  heat waves : increases (HC); further increase (HC); drastic increase (HC) Increased mortality from heat-waves: high risks; higher risks (HC);sustantial impact on health and mortality (HC) Undernutrition / dryland agriculture and livestock: high risk; higher risk (HC); very high risks

Emergence and intensity of regional climate change hot spots
Warming of 1.5°C or lessWarming of 1.5ºC-2°C
Warming > 2°C

L, likely
VL, very likely
LC, low confidenceMC, medium confidenceHC, high confidence

Small islands: Inundation risk : land exposed; tens of thousands displaced ; substantial, widespread impacts
 Coastal flooding: risks; high risks ; substantial and widespread impacts
 Fresh water stress : increased; projected aridity; substantial and widespread impacts
 # of warm days : increase; further increase (70 warm days/year), persistent heat stress incattle ; persistent heat stress Loss of coral reefs: 70-90%; most coral reefs ; loss of most coral reefs (VL)

|How do climate-related risks change
as a function of the level of global warming?

Confidence level : M, medium; H, high; VH; very highVery highHigh
Moderate
Undetectable

|How do climate-related risks for “Reasons For Concern” change
as a function of the level of global warming?

Confidence level : M, medium; H, high; VH; very highVery highHigh
Moderate
UndetectableAt 1.5°C compared to 2°C• Up to several hundred million fewer people
exposed to climate-related risk andsusceptible to poverty by 2050
• Disproportionately high risk for Arctic,
dryland regions, small island developing
states and least developed countries• Lower risks for health, livelihoods, foodsecurity, water supply, human security andeconomic growth

Jason Florio / Aurora Photos• Wide range of adaptation options which canreduce climate risks; less adaptation needs at
1.5°C

|

What are greenhouse gas emission pathways
compatible with limiting warming to 1.5°C?

https://data.ene.iiasa.ac.at/iamc-1.5c-explorer/26

|What are greenhouse gas emission pathways
compatible with limiting warming to 1.5°C?

Pathways with no or limited overshootPathways with a high overshoot27

|What are greenhouse gas emission pathways
compatible with limiting warming to 1.5°C?

28

Limiting warming to 1.5°C
Would require rapid, far-reaching andunprecedented changes in all systems
A range of technologies and behavioural changes
Scale up in annual investment in low carbon energy
and energy efficiency by factor of five by 2050
Renewables supply 70-85% of electricity in 2050
Coal declines steeply, ~zero in electricity by 2050

Deep emissions cuts in transport and buildings
Transitions in land use, scale depending on
mitigation portfolio
Urban and infrastructure system transitions,changes in urban planning practices
Mint Images / Aurora Photos

Where are we?

• National pledges are not enough to limit
warming to 1.5°C• Avoiding warming of more than 1.5°C
would require carbon dioxide emissions todecline substantially before 2030

Peter Essick / Aurora Photos

Climate change and sustainability• Ethical and fair transitions• Different pathways have different synergies
and trade-offs with UN Sustainable
Development Goals (SDGs)• Careful mix of measures to adapt to climatechange and reduce emissions can help
achieve SDGs

• Low energy demand, low material
consumption and low carbon food carryhighest benefits• Cooperation,governance, innovation andmobilisation of finance key for feasibility

Ashley Cooper/ Aurora Photos

Every half a degree matters

Every year matters
Every choice mattersipcc.ch/report/sr15 :Summary for Policy Makers
10 Frequently Asked Questions
5 Chapters
Glossary

May 2019
Emission
inventories

Oct. 2018

Sept. 2019

Globalwarming of
1.5 oC

Oceansand cryosphereTalanoa
dialogue
UNFCCCLandAug. 2019April 2021

October 2021

April 2022

The PhysicalScience Basis

Climate Change
Impacts,Adaptation andVulnerability

The Synthesis
ReportMitigationofClimate Change

July 2021

The IPCC Sixth Assessment Cycle

Global stocktake
2023
UNFCCCThank you for your attention

|Four illustrative model pathways
Fossil fuels and industry
Agriculture, forestry, land use
Billion tons CO2 per year (GtCO2/yr)

Bioenergy with CCSYear