Valerie Masson-Delmotte, Co-Chair of IPCC Working Group I

1. Climate Change
Valérie Masson-Delmotte
valmasdel
#showyourstripes

2. • Climate is changing everywhere, with visible impacts
• This is due to global greenhouse gas emissions
• On the near-term (horizon 2050), future changes are
inevitable and we must be prepared to reduce risks
• Long-term changes (beyond 2050) depend drastically on
greenhouse gas emissions in the next years and decades
• There are many options to act

3. A major scientific endeavour
17th C
Weather
instruments
19th C
Networks
Ice ages
Greenhouse
effect
Fluid physics
Thermodynamics
Radiative transfers
20th C
Past climate
Climate modelling
Chronology, proxies
Super computors
Satellites

4. 0
5000
10000
15000
20000
1970 1975 1980 1985 1990 1995 2000 2005 2010 2015
Number of peer-review papers with
the keyword
« climate change »

5. Physical science
basis
Synthesis report
Impact,
adaptation and
vulnerabilities
Mitigation
April 2021 April 2022October 2021
July 2021
Paris Agreement
2023 Global
Stocktake
1.5 o
C
Oct. 2018 Sept. 2019
August 2019
Talanoa
Dialogue
COP24
Usage des
terres
Océans
et cryosphère
Emission
inventories
May 2019
The 6th Assessment cycle
of the Intergovernmental
Panel on Climate Change
www.ipcc.ch
@IPCC_CH
1.5°C
Land
Ocean &
cryosphere

6. Physical
principles
Today’s
climate
Trends Process
Weather
forecast
Past climate Robustness
Reto Knutti, ETH Zürich
Climate modelling
www.nature.com/articles/nclimate3224

7. What is climate change?

8. Atmospheric concentration
CO2
CH4
N2O
Year
0 20001000
www.geosci-model-dev.net/10/2057/2017/
Human influence on atmospheric composition

9. Human influence on the global carbon cycle
CO2 in the
atmosphere
Coal, oil, gas (87%), deforestation (13%)100%
≈22% ≈29%
≈44%
Billion tons
CO2
2008-2017
www.globalcarbonproject.org
Uncertainty
≈5%

10. Since 1750
(W/m2)
 greenhouse
effect
- umbrella effect
of aerosols
= net warming
effect
Human influence on the Earth’s energy budget
www.ipcc.ch/ar5/wg1 Figure SPM.5 adapted by folk.uio.no/roberan

11. Nos activités agissent
sur le bilan d’énergie de la Terre
Climate is changing
due to the Earth’s energy imbalance
www.nature.com/articles/nclimate2876

12. Global warming

13. Global mean surface temperature change since 1850-1879 (°C)
Monthly observations
All causes combined
Human activities (5-95%)
Sun and volcanoes (5-95%)
Human influence on global climate

14. More
frequent
Global warming is affecting extreme events
Less
frequent
www.ipcc.ch/report/managing-the-risks-of-extreme-events-and-disasters-to-advance-
climate-change-adaptation/

15. Climate change hazards
www.nature.com/articles/nclimate2876
www.ipcc.ch/report/SROCC

16. www.ipcc.ch/report/SROCC

17. Impacts and risks for selected natural,
managed and human systems
www.ipcc.ch/report/SR15

18. Impacts and risks to marine life from climate change
www.ipcc.ch/report/SROCC

19. Risks from changes in land-based processes
as a result of climate change
www.ipcc.ch/report/SRCCL

20. Different socio-economic pathways affect
levels of climate-related risks
Low population growth, reduced
inequalities, food production in low
emission systems, effective land use
regulation, high adaptive capacity
www.ipcc.ch/report/SRCCL

21. www.ipcc.ch/report/SROCC
Sea level rise risks depend
on emissions and on response options

22. What are plausible futures?

23. Today’s choices determine future risks
Fast reduction
of emissions
Large increase of
emissions
Late reduction of
emissions
2019
Delayed action

24. If not us, who? If not now, when?

25. If not us, who? If not now, when?
• There are many options for action, and this requires new mindsets
and new skills (« climate literacy »)
- not just awareness raising, but skills
- systemic vision (beyond usual silos)
- understanding science (Earth system)
- understanding societal implications
- systems transitions (energy, land use, urban, industry, finance)
- societal transformation (law, best practices, demand side)
- potential and limits, co-benefits and trade-offs, enabling conditions
- building resilient, carbon neutral development pathways
• Training teachers www.oce.global
• Monitor, assess, benchmark « climate literacy »

26. If not us, who? If not now, when?
• Research and action to support transitions and
transformations
• Agenda of research and action for cities and
climate change
• Cultural heritage and climate change
• Transforming universities, living labs of
transitions :
- Environmental & carbon footprints
- Open data and student projects
- Researchers engaged with society
- Vision, targets, pathways, implementation
- Net zero emissions and resilience
- International benchmarking
- Creativity
www.ipcc.ch/report/SR15 and data.ene.iiasa.ac.at/iamc-1.5c-explorer
labos1point5.org
futureearth.org/2019/09/20/global-research-and-action-agenda-
on-cities-and-climate-change-science-published/
www.icomos.org
climateheritage.org

27. IPCC
IPCC
http://www.slideshare.net/ipcc-media/presentations
https://www.youtube.com/ipccgeneva
Find us on:
Website: http://ipcc.ch/
IPCC Secretariat: ipcc-sec@wmo.int
@IPCC_CH https://www.linkedin.com/company/ipcc
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THANK YOU FOR YOUR ATTENTION!
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