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Changements climatiques et santé: Le contexte climatique

Jean-Pascal van Ypersele (UCL) Vice-président du GIEC de 2008 à 2015

Twitter: @JPvanYpersele Conférence « changements climatiques et santé », CFDD, Sénat, Bruxelles, 26-10-2017

Merci au Gouvernement wallon pour son soutien à la www.plateforme-wallonne-giec.be et à mon équipe à l’Université catholique de Louvain pour son soutien

Saturn, as seen on 25-4-2016 from a 3 million km distance by the Cassini satellite launched in

October 1997, 40 years after Sputnik

That small blue dot is the Earth, a seen from Cassini, orbiting Saturn, 1.44 billion km from

us, on 19-7-2013

!!!!!!!!!!!!Apollo 17,!7 Dec. 1972!

Our atmosphere is thin and fragile (as seen by ISS crew on 31 July 2013)

Jean-Pascal van Ypersele (vanyp@climate.be)

2014,2015,2016=warmestyearssince1880

Source: NASA GISS

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Uccle n’est pas en reste:

Surfacedelaglacedemerarc-que(écartparrapportàlamoyenne)

Change in average sea-level change

IPCC AR5 WGI (2013)

Lesrécifscoralliensmeurent

AmericanSamoa(fromwww.globalcoralbleaching.org)

QoriKalisGlacier(Pérou):juillet1978

Source:Dr.LonnieThompson(OSU),viah7p://climate.nasa.gov/images-of-change#543-melCng-qori-kalis-glacier-peru

QoriKalisGlacier(Pérou):juillet2011

Source:Dr.LonnieThompson(OSU),viah7p://climate.nasa.gov/images-of-change#543-melCng-qori-kalis-glacier-peru

B. Holt - JPL

Greenland Ice Mass Loss 2002-2009 Derived From NASA GRACE Gravity Mission

Greenland

Chan

ge in

Ice

Mas

s Los

s Gig

aton

s

J. Wahr, U. Colorado

Velicogna, Geophysical Research Letters, 2009

•Contributes to sea level rise

Winter(DJF)seasonalchangesinheavyprecipita-on(%),2071-2100comparedto1971-2000

IPCC,AR5,WGII,Chap.23,p.1277

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InPuertoRico,HurricaneMariacreatedin2017theworsthumanitariancrisisintheUS

fordecades

Source:FEMA,24-9-2017

PourquoileGIEC(Grouped’expertsIntergouvernementalsurl’Evolu-onduClimat)?

Mandat:fournirauxdécideursunesourceobjec-ved’informa-onàpropos:

•  descausesdeschangementsclima-ques

•  desscénariospossiblesd’évolu-on

•  desconséquencesobservéesoufuturespourl’environnementetlesac-vitéshumaines

•  lesop-onsderéponsepossibles(adapta-on&abénua-on=réduc-ondesémissions).

OMM=Organisa-onMétéorologiqueMondialePNUE=ProgrammedesNa-onsUniespour

l’Environnement

Etabli par l’OMM et le PNUE en 1988

Que se passe-t-il dans le système climatique ?

Quels sont les risques ?

Que peut-on faire ?

IPCC AR5 Synthesis Report

Messages clés •! L’influence humaine sur le système climatique est

claire •! La poursuite des émissions de gaz à effet de serre

augmentera le risque d’impacts graves, répandus et irréversibles pour les populations et les écosystèmes

•! Alors que les changements climatiques représentent une menace pour le développement durable, il existe de nombreuses opportunités pour intégrer l’atténuation, l’adaptation, et la poursuite d’autres objectifs sociétaux

•! L’Humanité a les moyens de limiter les changements climatiques et de construire un avenir plus durable et plus résilient

AR5 WGI SPM, AR5 WGII SPM, AR5 WGIII SPM

QdE(Q36&'61#%-36N([%5(EFAf(/<''*:6+(&"#L'7(

Source: /4,288/;K4/V;.VK:8,<I,+-/:T..D23I4K,>.:&

(Lüthi et al.,2008, NOAA)

+30%

2015

The concentrations of CO2 have increased to levels

unprecedented in at least the last 800,000 years.

1000 years before present

CO

2 Con

cent

ratio

ns (p

pm)

Atmospheric concentrations of CO2!

AR3 AR2

AR1 AR4

A Progression of Understanding: Greater and Greater Certainty in Attribution

AR1 (1990): “unequivocal detection not likely for a decade”

AR2 (1995): “balance of evidence suggests discernible human influence”

AR3 (2001): “most of the warming of the past 50 years is likely (odds 2 out of 3) due to human activities”

AR4 (2007): “most of the warming is very likely (odds 9 out of 10) due to greenhouse gases”

IPCC

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Carbon cycle: unperturbed fluxes

Units: GtC (billions tons of carbon) or GtC/year (multiply by 3.7 to get GtCO2)

120

70.5

70

2300

Atmosphere pre-ind : 597

38000 Ocean

3700

respiration

Physical,

Chemical, and Biological processes

photosynthesis 119.5

vanyp@climate.be

280 ppmv (1ppmv = 2.2 GtC) GtC

Carbon cycle: perturbed by human activities (numbers for the decade 1990-1999s, based on IPCC AR4)

Units: GtC (billions tons of carbon) or GtC/year

120

70.5

70

2300

Atmosphere pre-ind : 597

38000 Ocean

3700

GtC + 3.2/yr

déforestation (& land use changes) Fossil fuels

6.4

-244 +120 -40

1.6 sinks

2.6 respiration

2.2

Physical, Chemical, and

Biological processes

photosynthesis 119.5

vanyp@climate.be Stocks!

280 ppmv + 1.5 ppmv/yr (1ppmv = 2.2 GtC)

RCP Scenarios: Atmospheric CO2 concentration

AR5, chapter 12. WGI- Adopted version / subject to final copyedit

Three stabilisation scenarios: RCP 2.6 to 6 One Business-as-usual scenario: RCP 8.5

Only the lowest (RCP2.6) scenario maintains the global surface temperature increase above the pre-industrial level to less than 2°C with at

least 66% probability

(IPC

C 2

013,

Fig

. SP

M.7

a)

18-20000 years ago (Last Glacial Maximum) With permission from Dr. S. Joussaume, in « Climat d’hier à demain », CNRS éditions.

Today, with +4-5°C globally With permission from Dr. S. Joussaume, in « Climat d’hier à demain », CNRS éditions.

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Sea level due to continue to increase

(IPC

C 2

013,

Fig

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M.9

)

(Ref: 1986-2005)

With 1 metre sea-level rise: 63000 ha below sea-level in Belgium (likely in 22nd century, not impossible in 21st century)

(NB: flooded area depends on protection)

Source: J.P. van Ypersele et P. Marbaix (2004) See www.climate.be/impacts

(Time 2001)

Effets sur le Delta du Nil, où vivent plus de 10 millions de personnes à moins d’1 m d’altitude

IPCC AR5 Synthesis Report

P,2%&19(%#'(%*#'%)5("6)'#W%5(

•! Tropics!to!the!poles •! On!all!continents!and!in!the!ocean •! Affecting!rich!and!poor!countries (but the

poor are more vulnerable everywhere)

AR5 WGII SPM

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IPCC, AR5, SPM, Figure SPM.8

Regional key risks and risk reduction through adaptation

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HumanHealth:Impacts,Adapta-on,andCo-Benefits(1)

•  ThehealthofhumanpopulaConsissensiCvetoshicsinweatherpa7ernsandotheraspectsofclimatechange(veryhighconfidence).

•  UnClmid-centuryclimatechangewillactmainlybyexacerbaCnghealthproblemsthatalreadyexist(veryhighconfidence).

IPCC,AR5,WGII,chap.11,ExecuCveSummary,p.713

HumanHealth:Impacts,Adapta-on,andCo-Benefits(2)

•  Inrecentdecades,climatechangehascontributedtolevelsofillhealth(likely)thoughthepresentworldwideburdenofillhealthfromclimatechangeisrelaCvelysmallcomparedwithotherstressorsonhealthandisnotwellquanCfied

IPCC,AR5,WGII,chap.11,ExecuCveSummary,p.713

HumanHealth:Impacts,Adapta-on,andCo-Benefits(3)

•  Impactsonhealthwillbereduced,butnoteliminated,inpopulaConsthatbenefitfromrapidsocialandeconomicdevelopment(highconfidence),parCcularlyamongthepoorestandleasthealthygroups(veryhighconfidence).

•  InaddiContotheirimplicaConsforclimatechange,essenCallyalltheimportantclimate-alteringpollutants(CAPs)otherthancarbondioxide(CO2)havenear-termhealthimplicaCons(veryhighconfidence)

IPCC,AR5,WGII,chap.11,ExecuCveSummary,p.713

HumanHealth:Impacts,Adapta-on,andCo-Benefits(4)

•  SomepartsoftheworldalreadyexceedtheinternaConalstandardforsafeworkacCvityduringtheho7estmonthsoftheyear.

•  ThemosteffecCvemeasurestoreducevulnerabilityintheneartermareprogramsthatimplementandimprovebasicpublichealthmeasuressuchasprovisionofcleanwaterandsanitaCon,secureessenCalhealthcareincludingvaccinaConandchildhealthservices,increasecapacityfordisasterpreparednessandresponse,andalleviatepoverty(veryhighconfidence).

IPCC,AR5,WGII,chap.11,ExecuCveSummary,p.713-714

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•! The 2015 Lancet Commission on Climate Change and Health report stated: “The effects of climate change are being felt today, and future projections represent an unacceptably high and potentially catastrophic risk to human health.”

•! BUT it also underscored that Tackling climate change could be the greatest global health opportunity of the 21st century.

Cumulative emissions of CO2 largely determine global mean surface warming by the late 21st century and beyond.

Fig. SPM.10

© IP

CC

201

3

Fig. SPM.10

Limiting climate change will require substantial and sustained reductions of greenhouse gas emissions.

© IP

CC

201

3

IPCC AR5 Synthesis Report

The window for action is rapidly closing 65% of the carbon budget compatible with a 2°C goal is already used NB: this is with a probability greater than 66% to stay below 2°C NB: this is with a probability greater than 66% to stay below 2°C

Amount Used 1870-2011:

1900 GtCO2

Amount Remaining:

1000 GtCO2

Total Carbon Budget:

2900 GtCO2

AR5 WGI SPM NB: Emissions in 2011: 38 GtCO2/yr

IPCC AR5 Synthesis Report

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IPCC AR5 Synthesis Report

Mitigation Measures

More efficient use of energy

Greater use of low-carbon and no-carbon energy - Many of these technologies exist today - But worldwide investment in research in support of GHG mitigation is small!

Improved carbon sinks - Reduced deforestation and improved forest management

and planting of new forests - Bio-energy with carbon capture and storage

Lifestyle and behavioural changes AR5 WGIII SPM

IPCC AR5 Synthesis Report

The Choices Humanity Makes Will Create Different Outcomes (and affect prospects for effective adaptation)

With substantial mitigation

Without additional mitigation

Change in average surface temperature (1986–2005 to 2081–2100) AR5 WGI SPM

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•! A global effort is required to reduce anthropogenic greenhouse emissions and address the health impact of climate change. The United States must commit to taking both a leadership and collaborative role in developing, implementing and ensuring the success of such a global effort and in reducing its own contributions to greenhouse emissions. Climate change adaptation strategies must be established and mitigation measures must be adopted.

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Adaptation is “adjustment in natural or human systems to a new or changing environment that exploits beneficial opportunities or moderates negative effects.” (1)

Problem •! Drought in Africa

•! Extreme Heat Events in

Europe

•! Urban flooding in North America

Image

Adaptation Strategy (1) •! Reducing non-climate stressors

on water rec., sustainable urban devel., strengthen institutional capacities for demand mgmt.

•! Warning systems, reduced emissions to improve air qual., residence, workplace modifications

•! Use of pervious surfaces, rooftop gardens; wetland conservation, planting of mangroves, coast-protecting vegetation.

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PleasegoandseethelatestmoviewithAlGore(2017):

An Inconvenient Sequel: Truth to Power

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Jean-Pascal van Ypersele (vanyp@climate.be)

Pour en savoir plus : !! www.ipcc.ch : GIEC ou IPCC !! www.climate.be/vanyp : beaucoup de mes dias !! www.plateforme-wallonne-giec.be : Plateforme

wallonne pour le GIEC (e.a., Lettre d’information) !! www.my2050.be : calculateur de scénarios !! www.realclimate.org : réponses aux semeurs de doute !! www.skepticalscience.com : idem

!! Sur Twitter: @JPvanYpersele @IPCC_CH