Climate and climate change sciences: 30 years of IPCC ... · Climate Change WGII Impacts,...

Climate and climate change sciences:

30 years of IPCC assessment reports

Valérie Masson-Delmotte

@valmasdel

Global emissions from fossil fuel and industry: 36.2 ± 2 GtCO2 in 2016, 62% over 1990

Projection for 2017: 36.8 ± 2 GtCO2, 2.0% higher than 2016

Estimates for 2015 and 2016 are preliminary. Growth rate is adjusted for the leap year in 2016.Source: CDIAC; Le Quéré et al 2017; Global Carbon Budget 2017

Emissions from fossil fuel use and industry

Uncertainty is ±5% for one standard deviation

(IPCC “likely” range)

http://cdiac.ornl.gov/trends/emis/meth_reg.html

https://doi.org/10.5194/essd-2017-123

http://www.globalcarbonproject.org/carbonbudget/

Haustein et al, Scientific Report, 2017

Warming due to human influence

O’Neil et al, NCC, 2017

More warming = more risks

Global warming

(°C) above 1850-

1900

Unique and

threatened

systems

Extreme

eventsDistribution

of impactsGlobal

aggregated

impacts

Large scale

singular

events

2017

Paris Agreement mechanism

Rogelj et al, Nature, 2016

Long term target

Talanoa Dialogue 2018

Global stocktake 2023adaptation, mitigation, finance

Emission decrease

towards carbon

neutrality

Antiquity Middle

Age

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

A major scientific endeavour

From knowledge production …

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 »

…to the assessment of the state of knowledge

The IPCC assesses the scientific, technical and socio-economic

information relevant to understanding the scientific basis of risk of

human-induced climate change, its potential impacts and options for

adaptation and mitigation.

The IPCC is organized in Working Groups and one Task Force :

- WGI : the physical science basis

- WGII : impacts, adaptation and vulnerability

- WGIII : mitigation of climate change

- Task Force on national greenhouse gas inventories

IPCC reports must be policy-relevant but not policy-prescriptive

COMPREHENSIVE, OBJECTIVE, OPEN AND TRANSPARENT BASIS

Science/Policy Interface

Plenary

Bureaux

Working Group (WG) I

The Physical

Science Basis

WGIII

Mitigation of

Climate Change

WGII

Impacts,

Adaptation &

Vulnerability

Task Force on

National

Greenhouse

Gas Inventories

Authors

Expert

Reviewers

Review

Editors

Intergovernmental Panel: 195 member States

appointing National Focal Points

IPCC – jointly established by WMO and UNEP, action endorsed by the UN General Assembly

Hundreds of scientists and experts from around the world are involved in the preparation of IPCC

reports

From published literature to Summaries for Policy-Makers

• Assessments are based on published literature, preferably peer-reviewed; updates of figures/tables using published methodology are OK, but new research is not.

• Assessment statements must be traceable and the lines of evidence made clear.

• Executive Summaries distill key results/messages from each chapter, and Summary for Policy Makers (SPM) distills even further.

– SPM must be approved line-by-line by governments.

– Underlying chapter text provides foundation for SPM.

How does an assessment differ from a review?

• It is intended to objectively summarize the state of (scientific) knowledge in

a balanced way, including an assessment of confidence/uncertainty.

• It is to be policy relevant (and not policy prescriptive); therefore it need not

comprehensively cover all of the literature in the field.

Indicative bullet points provide guidance

• It is a consensus document produced by the author team, not a collection of

individual contributions. Assessment statements should be agreed as a

group, based on expert judgment.

• Calibrated language is an essential element.

Using a calibrated language

to report confidence in findings

Concrete example : Chapter section and summary statement

{this section is 14 pages long}

Concrete example … Chapter Executive Summary …

Concrete example : … Summary for Policy Makers …

1988

IPCC – jointly

established by

WMO and UNEP

1990

FAR

1995

SAR

2001

TAR

2007

AR4 AR5 AR6

2013-2014

UNFCCC

Global

Stocktake

2023

1970s-1980s

Kyoto

Protocol

UNFCCC Adaptation 2 °C limit Paris Agreement

Nobel Peace Prize

2018

1990

broad overview of climate

change science, discussion

of uncertainties and

evidence of warming

1995

“The balance of evidence

suggests a discernible

human influence on global

climate”

2001

“new and stronger

evidence that most of the

warming observed over the

last 50 years is attributable

to human activities”

2007

"Warming of the

climate system is

unequivocal…"

2013

“Human influence

on the climate

system is clear.”

Improvements:

Methods of attribution : global scale

IPCC AR5

New developments for single extreme events

Magnusson et al 2013 WMR

Example : role of high sea

surface temperature on wind

speeds of Hurricane Sandy

1950s 1960s 1970s 1980s 1990s

Emergence of sea level science

2000s 2010s

-

Extreme sea levelAstronomical theory

and ice ages

Vulnerability of West

Antarctic ice sheet

Observed sea

level rise

Sea level projections

Fast glacier flow

Irreversibility

Interior rivers

Regional

aspectsGlacier

mass

balance

Ice sheet - ocean

Coastal habitats

Sea level in the FAR (1990) and AR5 (2013)

Over the last century, global sea level has increased by 10-20 cm

Over the period 1901 to 2010, global mean sea level rose by 0.19 [0.17 to 0.21]

m.

1.7 [1.5 to 1.9] mm yr–1 between 1901 and 2010

2.0 [1.7 to 2.3] mm yr–1 between 1971 and 2010,

3.2 [2.8 to 3.6] mm yr–1 between 1993 and 2010.

Over the period 1993 to 2010, global mean sea level rise is, with high confidence,

consistent with the sum of the observed contributions from ocean thermal

expansion due to warming, from changes in glaciers, Greenland ice sheet, Antarctic

ice sheet and land water storage.

It is very likely that there is a substantial anthropogenic contribution to the

global mean sea level rise since the 1970s.


Under the business as usual scenario, the predicted rise is about 65cm by the end

of the next century. There will be significant regional variations.

For RCP8.5, the rise by the year 2100 will likely be

in the range of 0.52 to 0.98 (relative to 1986-2005)

There is currently insufficient evidence

to evaluate the probability of specific levels

above the assessed likely range.

Sea level rise will not be uniform. By the end of the 21st century, it is very likely that

sea level will rise in more than about 95% of the ocean area. About 70% of the

coastlines worldwide are projected to experience sea level change within 20% of the

global mean sea level change.

Although, over the next 100 years, the effect of the Antarctic and Greenland ice

sheets is expected to be small they make a major contribution to the

uncertainty in predictions

Changes in outflow from both ice sheets combined will likely make a

contribution in the range of 0.03 to 0.20 m by 2081−2100

Only the collapse of marine-based sectors of the Antarctic ice sheet, if initiated,

could cause global mean sea level to rise substantially above the likely range

during the 21st century. However, there is medium confidence that this

additional contribution would not exceed several tenths of a meter of sea level

rise during the 21st century.



Even if greenhouse forcing increased no further, there would still be a

commitment to a continuing sea level rise for many decades and even centuries

due to delays in climate ocean and ice mass responses

It is virtually certain that global mean sea level rise will continue beyond 2100,

with sea level rise due to thermal expansion to continue for many centuries.

RCP 2.6 : <1 m by 2300

RCP8.5 : 1 m to more than 3 m

Sustained mass loss by ice sheets would cause larger sea level rise, and some

part of the mass loss might be irreversible. There is high confidence that sustained

warming greater than some threshold

would lead to the near-complete loss of the

Greenland ice sheet over a millennium or more,

causing a global mean sea level rise of up to 7 m.

m

The most severe effects of sea level rise are likely to result from extreme events

(for example, storm surges) the incidence of which may be affected by climatic

change

It is very likely that there will be a significant increase in the occurrence of future

sea level extremes by 2050 and 2100. This increase will primarily be the result of an

increase in mean sea level (high confidence), with the frequency of a particular sea level

extreme increasing by an order of magnitude or more in some regions by the end of the

21st century. There is low confidence in region-specific projections of storminess

and associated storm surges.


64%

36%

Developed Countries

Developing Countries & Economies in

Transition

79%

21%

Male writing team members

Female writing team members

63%

37%

New to the IPCC process

Previously involved

The Fifth Assessment Report (AR5)

830 Coordinating Lead Authors, Lead Authors and Review Editors

from 85 countries

2030 international agenda

Paris Agreement

Knowledge: risk management & solutions

Specificities of the IPCC AR6

• More experts from developing countries

• More integration across Working Groups

• High level scenarios and concrete steps

• Connections with sustainable development goals

• Focus on solutions linked to domestic challenges

Poverty alleviation, job creation, health, innovation, energy access…

• Strengthen relevance for a variety of stakeholders

Three Conventions (climate, biodiversity, desertification)

Subnational policy makers (cities…)

Business, industry, finance…

Aspirations for the AR6

Improve communication (graphics, SPM, FAQ…)

IPCC report preparation steps

Cut-off dates for

cited references

The Physical Science Basis

The Synthesis Report

Climate ChangeImpacts,

Adaptation and Vulnerability

Mitigationof

Climate Change

April 2021 April 2022October 2021

July 2021

Global stocktake2023

UNFCCC

Global warming of

1.5 oC

Oct. 2018 Oct. 2019

Aug. 2019

FacilitativedialogueUNFCCC

Land

Oceans and cryosphere

Schedule

Cities and Climate Change Science Conference

Emissioninventories

May 2019

March2018

May 2018 Expert Meeting on Short Lived Climate Forcers

May 2018 Expert Meeting on Assessing Climate Information for Regions

Chapter 1: Framing and context

Chapter 2: Mitigation pathways compatible with 1.5°C

in the context of sustainable development

Chapter 3: Impacts of 1.5°C global warming on natural

and human systems

Chapter 4: Strengthening and implementing the global

response to the threat of climate change

Chapter 5: Sustainable development, poverty

eradication and reducing inequalities

Global warming of 1.5°C (SR1.5)

15

40

60

50

20


Chapter 2: Land-climate interactions

Chapter 3: Desertification

Chapter 4: Land degradation

Chapter 5: Food security

Chapter 6 : Interlinkages between desertification, land

degradation, food security, and greenhouse gas fluxes

: synergies, trade-offs and integrated response options

Chapter 7 : Risk management and decision making

In relation to sustainable development

IPCC Special Report on Climate

Change and Land (SRCCL)

15

50

35-40

40

50

40

40


Chapter 2: High mountain areas

Chapter 3: Polar regions

Chapter 4: Sea level rise and implications for low lying

islands, coasts and communities

Chapter 5: Changing ocean, marine ecosystems, and

dependent communities

Chapter 6 : Extremes, abrupt changes and managing

risks

Box : Low lying islands and coasts

IPCC Special Report on the Ocean and

Cryosphere in a Changing Climate (SROCC)

15

30

50

50

65

20

<5

WGI OutlineSummary for Policy Makers

Technical Summary

Chapter 1: Framing, context, methods

Chapter 2: Changing state of the climate system

Chapter 3: Human influence on the climate system

Chapter 4: Future global climate: scenario-based projections and near-term information

Chapter 5: Global carbon and other biogeochemical cycles and feedbacks

Chapter 6: Short-lived climate forcers

Chapter 7: The Earth’s energy budget, climate feedbacks, and climate sensitivity

Chapter 8: Water cycle changes

Chapter 9: Ocean, cryosphere, and sea level change

Chapter 10: Linking global to regional climate change

Chapter 11: Weather and climate extreme events in a changing climate

Chapter 12: Climate change information for regional impact and for risk assessment

Annexes incl. options for a Regional Atlas and Technical Annexes

Glossary

Index

Large-scale climate change


Technical Summary














Glossary

Index

Climate processes

Regional climate

information


Technical Summary














Glossary

Index


Technical Summary












Chapter 12: Climate change information for regional impact and risk for assessment


Glossary

Index

Link to WGII

Link to WGIII

WGII ChaptersChapter 1: Point of departure and key concepts

SECTION 1: Risks, adaptation and sustainability for systems impacted by climate change Chapter 2: Terrestrial and freshwater ecosystems and their services

Chapter 3: Ocean and coastal ecosystems and their services

Chapter 4: Water

Chapter 5: Food, fibre, and other ecosystem products

Chapter 6: Cities, settlements and key infrastructure

Chapter 7: Health, wellbeing and the changing structure of communities

Chapter 8: Poverty, livelihoods and sustainable development

SECTION 2: Regions Chapter 9: Africa

Chapter 10: Asia

Chapter 11: Australasia

Chapter 12: Central and South America

Chapter 13: Europe

Chapter 14: North America

Chapter 15: Small Islands

SECTION 3: Sustainable development pathways: integrating adaptation and mitigation Chapter 16: Key risks across sectors and regions

Chapter 17: Decision-making options for managing risk

Chapter 18: Climate resilient development pathways* *connection to WG III

ANNEX I: Regional Atlas

CROSS-CHAPTER PAPERS

• Biodiversity hotspots (land, coasts and oceans)

• Cities and settlements by the sea

• Deserts, semi-arid areas, and desertification

• Mediterranean region

• Mountains

• Polar regions

• Tropical forests

15. Investment and finance16. Innovation, technology development and transfer

5: Demand, services and social aspects of mitigation6: Energy systems 9. Buildings7. Agriculture, Forestry, and Other Land Uses 10. Transport8. Urban systems and other settlements 11. Industry12. Cross sectoral perspectives

Outline of WG III AR6 on mitigationFraming (1 chapter)

High-level assessment of emission trends, drivers and pathways (3 chapters)

Sectoral chapters (8 chapters)

Institutional drivers (2 chapters)

Synthesis (1 chapter)

17. Accelerating the transition in the context of sustainable development

13. National and sub-national policies and institutions 14. International cooperation

1. Introduction and framing

2. Emissions trends and drivers3. Mitigation pathways compatible with long-term goals4. Mitigation and development pathways in the near- to mid-term

Set up sustainable development as key framing concept

Balancing sources and sinks/warming levels

NDCs, emissions peaking, mid-century long-term low greenhouse

gas emission development strategies

Orients sectors to human needs

The sectoral core: maps on to inventories

Financial flows + technological innovation

Synthesis sustainable development in different geographical scales

Financial and technological drivers (2 chapters)

Responses not captured by sectoral framing

Institutions, policies and cooperation

The Physical Science Basis

The Synthesis Report

Climate ChangeImpacts,

Adaptation and Vulnerability

Mitigationof

Climate Change

April 2021 April 2022October 2021

July 2021

Global stocktake2023

UNFCCC

Global warming of

1.5 oC

Oct. 2018 Oct. 2019

Aug. 2019

FacilitativedialogueUNFCCC

Land

Oceans and cryosphere

Schedule

Cities and Climate Change Science Conference

Emissioninventories

May 2019

March 2018

May 2018 Expert Meeting on Short Lived Climate Forcers

May 2018 Expert Meeting on Assessing Climate Information for Regions

Cut-off dates for reports

Report Cut-off dates for

submitted papers to

be cited in Second

Order Drafts

Cut-off dates for

papers accepted for

publication to be cited

in report

SR1.5 01 November 2017 15 May 2018

SROCC October 2018 May 2019

SRCCL September 2018 April 2019

AR6, WG1 31 January 2020 15 October 2020

Author teams

Coordinating Lead Authors (CLAs)

Lead Authors (LAs)

Review Editors (REs)

Contributing Authors (CA)

Chapter Scientists (CS)

2017 2018 2019

SR15 FOD – JulySOD – JanApproval – Oct

SRCCL FOD – MaySOD – Oct

Approval – Aug

SROCC FOD – AprSOD – Nov

Approval – Sept

Next review processes

Outreach Activities

Closing remarks

• Multiple roles of IPCC reports :

- assessment of the state of knowledge for governments

- synthesis of available research, regional results into global context

- identification of knowledge gaps and uncertainties

- maturation of science and stimulation of research

- teaching

• New knowledge is vital for IPCC assessments

• The review process is crucial for the quality of the assessment

• AR6 : a new IPCC approach with 3 special reports

• Which approach for the AR7 and beyond?

@IPCCNews

IPCC_Climate_Change

http://www.slideshare.net/ipcc-media/presentations

https://www.youtube.com/c/ipccgeneva

Find us on:

Website: http://ipcc.ch/

IPCC Secretariat: [email protected]

IPCC Press Office: [email protected]

@IPCC_CH

https://www.linkedin.com/company/ipcc

https://www.flickr.com/photos/ipccphoto/sets/

https://vimeo.com/ipcc

THANK YOU FOR YOUR ATTENTION!

For more information:

http://ipcc.ch/

mailto:[email protected]

mailto:[email protected]

Chapter 1:

Framing, context, methods

Executive Summary

• Synthesis of key findings from AR5 and earlier assessment reports, and

connections to AR6 Special Reports

• Framing of the physical science information relevant for mitigation,

adaptation, and risk assessment in the context of the Global Stocktake

• Assessment approach

• Observational and reanalysis developments since the AR5

• Model and experimental design developments since the AR5

• Emissions and forcing scenarios

• Treatment and evaluation of uncertainty throughout the report

Frequently Asked Questions

Chapter 2:

Changing state of the climate system

Executive Summary

• Multi-millennial context, pre-industrial to present day

• Natural and anthropogenic forcings

• Radiative forcing

• Large-scale indicators of observed change in the atmosphere, ocean,

cryosphere, land, and biosphere

• Modes of variability


Chapter 3:

Human influence on the climate system

Executive Summary

• Overview of model performance and development since the AR5

• Simulated large-scale indicators of change in the atmosphere, ocean,

cryosphere, land, and biosphere

• Simulated modes of variability

• Natural variability versus anthropogenically-forced change

• Attribution of large-scale observed changes


Chapter 4:

Future global climate: scenario-based projections

and near-term information

Executive Summary

• Projections of global mean surface temperature and other key global

indicators

• Evaluation of multi-model ensemble methods

• Large scale patterns of climate change

• Committed climate response, climate targets, overshoot, irreversibility,

abrupt change

• Climate response to greenhouse gas removal scenarios

• Climate response to solar radiation management scenarios

• Interplay between internal variability and response to forcings, including

short-lived forcers

• Variability and unexpected changes of global mean surface temperature

• Near-term predictability, sources and capabilities

• Synthesis of climate information in the near-term


Chapter 5:

Global carbon and other biogeochemical cycles and

feedbacks

Executive Summary

• Feedbacks between climate and biogeochemical cycles, including

paleoclimate information

• Ocean acidification

• Historical trends and variability of CO2, CH4 and N2O; sources and sinks

• Projections of global biogeochemical cycles from near-term to long-term

• Abrupt change, irreversibility

• Model evaluation, emergent constraints

• Transient climate response to cumulative emissions and remaining carbon

budgets for climate targets

• Biogeochemical implications of land and coastal management mitigation

options including greenhouse gas removal

• Biogeochemical implications of solar radiation management scenarios


Chapter 6:

Short-lived climate forcers

Executive Summary

• Key global emissions: global overview, natural, anthropogenic, historical

and scenarios

• Observed and reconstructed concentrations and radiative forcing

• Direct and indirect-aerosol forcing

• Implications for greenhouse gas lifetimes

• Implications of different socio-economic and emission pathways, including

urbanisation, for radiative forcing

• Connections to air quality and atmospheric composition


Chapter 7:

The Earth’s energy budget, climate feedbacks,

and climate sensitivity

Executive Summary

• Energy budget and its changes through time

• Radiative forcing: definitions, estimates, and its representation in models

• Climate feedbacks

• Sensitivity of the climate system: methods and uncertainty

• Empirical constraints on the sensitivity of the climate system, including

paleoclimate

• Global warming potential, global temperature change potential, and other

metrics


Chapter 8:

Water cycle changes

Executive Summary

• Observations, models, methods and their reliability

• Past, present and projected changes, trends, variability and feedbacks in

the physical components of the water cycle

• Circulation, processes and phenomena (e.g. monsoon systems) affecting

moisture and precipitation patterns, including extremes

• Cloud-aerosol processes affecting the water cycle

• Changes in seasonality of natural storage and water availability

• Abrupt change

• Confidence in projections


Chapter 9:

Ocean, cryosphere, and sea level change

Executive Summary

• Past and future changes in ocean circulation and properties (trends,

variability and extremes)

• Past and future changes in marine and terrestrial cryosphere

• Evaluation of models and projection methods

• Detection and attribution

• Past global and regional sea level changes

• Projections of global and regional sea level change

• Abrupt change and long-term commitment

• Extreme water levels (tides, surge and ocean waves)


Chapter 10:

Linking global to regional climate change

Executive Summary

• Regional phenomena, drivers, feedbacks and teleconnections

• Regional scale observations and reanalyses

• Interplay between internal variability and forced change at the regional

scale, including attribution

• Evaluation of model improvements, methods, including downscaling and

bias adjustment and regional specificities

• Confidence in regional climate information, including quantification of

uncertainties

• Scale specific methodologies e.g. urban, mountains, coastal, catchments,

small islands

• Approaches to synthesizing information from multiple lines of evidence


Chapter 11:

Weather and climate extreme events in a changing climate

Executive Summary

• Extreme types encompassing weather and climate timescales and

compound events (including droughts, tropical cyclones)

• Observations for extremes and their limitations, including paleo

• Mechanisms, drivers and feedbacks leading to extremes

• Ability of models to simulate extremes and related processes

• Attribution of changes in extremes and extreme events

• Assessment of projected changes of extremes and potential surprises

• Case studies across timescales


Chapter 12:

Climate change information for regional impact and for risk

assessment

Executive Summary

• Framing: physical climate system and hazards

• Region-specific integration of information, including confidence

• Information (quantitative and qualitative) on changing hazards: present

day, near term and long term

• Region-specific methodologies

• Relationship between changing hazards, global mean temperature

change, scenarios and emissions


“Ultimately what we do about climate issues depends upon the state of our

scientific knowledge. Only to the extent that we have understanding can we

help our governments.

Governments wish to know where to focus effort and resources. The

international resources that can be made available to deal with climatic

problems are limited. This is so not merely because finances are limited, but

because the number of scientists capable of working effectively on these

problems is limited.

Because of this, efforts must be focused on those climatic problems where

there is an urgent need for answers, and where the state of our scientific

knowledge leads us to believe that it may be possible for science to make a

useful contribution.”

Robert White, Keynote address, World Climate Conference, 1979

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Climate and climate change sciences: 30 years of IPCC ... · Climate Change WGII Impacts,...

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