AA climateclimate scenarioscenario takingtaking intointo accountaccount landland--useusechangechange

Aurore VOLDOIRE, Jean-François ROYER

CNRM/GMGEC

aurore.voldoire@meteo.fr

OutlineOutline

Introduction :

Why take into account vegetation changes inside climate scenarios?

Why take into account land-use changes inside climate scenarios?

Chosen method : Coupling CNRM-CM3 with IMAGE2.2

Description of the coupling scheme

The simulation

Results

Simulated climate perspective

Vegetation perspective

Conclusions / Future work

WhyWhy include vegetationinclude vegetation changeschanges within climatewithin climate scenariosscenarios??

GCM

CO2

Other greenhousegases (GHGs)

CH4

N2O

CFC11

Ozonechemistry Ozone

precursors

CO

Halons

Aérosols

directeffect

indirecteffects

B2B1A2A1FA1TA1B

Vegetation

Importance of land useImportance of land use

Vegetation fraction Roughtness length

Zonal anomalies of surface properties[2090-2099] –[1970-1979]

[70N-90N]

[50N-70N]

[30N-50N]

[10N-30N]

[10S-10N]

[30S-10S]

[50S-30S]

[70S-50S]

map with cultures

natural vegetation

Introduction

Method

Results

Conclusion

TheThe chosen approachchosen approach

Vegetation mapGHG and aerosolconcentrations

TemperaturePrecipitation

Integrated impact

model

IMAGE2.2

(developed at RIVM, TheNetherlands)Alcamo et al. (1998)

General circulation Model

AOG

ARPEGE (atmosphere)OPA (ocean) –IPSL/LodycGELATO (sea ice)ISBA (land surface scheme)

Introduction

Method

Results

Conclusion

Modelling ofenergydemand

Scenario : demographic and economic projection= definition of the needs

Emissions and land use changes

RETROACTIONS

(simple) carbon cycle and atmospheric chemistry

EBM model of climate change (R and T)

Concentration changes

Model of evolution ofcontinental surfaces

(natural vegetation, cattle,cultures,…)

Hypothes on evolution of population and economy

Components ofComponents of thethe IMAGE modelIMAGE modelIntroduction

Method

Results

Conclusion

SimulationSimulation methodmethod ofof thethe vegetationvegetation covercover

Vegetation maps in2050 computed for the

A2 scenario

Potential vegetation

Cultures

Pâtures

F. jeune abandonnée

Plantation

Glace

Toundra

Toundra arbustive

F. boréale

F. de conifères

F. mixte tempérée

F. décidue tempérée

F. mixte chaude

Steppe

Désert

Arbustes

Savane

Savane boisée

F. tropicale

Natural vegetation

Actual vegetation

Introduction

Method

Results

Conclusion

Energydemand

Scenario

Emissions and land use changes

RETROACTIONS

(simple) carbon cycle and atmospheric chemistry

Climat

Concentration changes

continental surfaces

Hypotheses

Introduction of ARPEGE/OPA/GELATOIntroduction of ARPEGE/OPA/GELATO insideinside IMAGE2.2IMAGE2.2Introduction

Method

Results

Conclusion

Climate (CNRM-CM3)ARPEGE OPA

ISBA GELATOOASIS

Scénariod’émission-

concentration

T, P

IMAGE 2.2(RIVM)

O3Precursors

Vegetation mapsGHGs& Aérosols

Climatemeans

Ozone chemistryMOBIDIC

5 years

O3

ZonalTransports

AtmosphereARPEGE-Climat

Coupler

OceanOPAG

Sea iceGELATO

24 h

RiverroutingTRIP

CouplerOASIS

Coupler

Continental SurfacesISBA

Coupler

AOG

The coupling schemeThe coupling schemeIntroduction

Method

Results

Conclusion

ScenarioScenario simulationsimulation

IMAGE2.2

1765

Equilibration of thecarbon cycle model

•historicalemissions of CO2

•historicalconcentrations ofother GHGs

Evaluation ofvegetation mapswith the observedclimate

emissions due tosimulated land use,others are historical

CNRM-CM3

20 years of simulationwith constant forcings

(1970)

Forcings producedby IMAGE

Scenario

Full coupling

19901970 2100

First coupledsimulation with an A2

scénario:A2-IM-CM3

Introduction

Method

Results

Conclusion

SimulatedSimulated globalglobal temperaturetemperature changechangeIntroduction

Method

Results

Conclusion

CNRM-CM3forced by SRESconcentrations

CNRM-CM3coupled to

IMAGE

concentrationconcentration scenariosscenarios

Simulations desconcentrations parIMAGE

SRES scenarioThe concentration scenarios

produced by IMAGE do notdepend much on the thesimulated climatic change

The SRES concentrationscenario is not much differentfrom the IMAGE scenario

No explanation for the suddenchange observed in temperature

Abrupt change ofAbrupt change of thethe arcticarctic seasea--iceice covercover

Aire de la glace en Arctique

Tendance glissante sur 15 ans de l’aire de glace Arctique

95%

95%

99%

99%

Introduction

Method

Results

Conclusion

GeographicGeographic distribution ofdistribution of thethe warmingwarming

Date from which the IMAGE/CNRM-CM3 simulation stays warmer than theCNRM-CM3 in annual mean over the following 15 years

Region where thevegetation albedo issmaller when usingthe IMAGE vegetationmap

Introduction

Method

Results

Conclusion

SimulatedSimulated change ofchange of vegetationvegetation

Cultures

Pâtures

F. jeune abandonnée

Plantation

Glace

Toundra

Toundra arbustive

F. boréale

F. de conifères

F. mixte tempérée

F. décidue tempérée

F. mixte chaude

Steppe

Désert

Arbustes

Savane

Savane boisée

F. tropicale

1970 2100

Différence

Introduction

Method

Results

Conclusion

SeasonalSeasonal cyclecycle anomalyanomaly overover AmazoniaAmazonia

Daily thermal amplitude Precipitation

Total evaporation Evapotranspiration

Sensible heat flux

Computed as difference between the 2070-2099 and the 1960-1989 periods

Modification of the mean climate, but also of extremes :

IPCC standard simulation

Simulation with IMAGE

IPCC standard simulation

Simulation with IMAGE

-23941

+84436Maximum Nb ofconsecutive drydays

+33936

+13332Nb of days whereprécip > 10mm.j-1

Différence2070-20991960-1999

Introduction

Method

Results

Conclusion

PerspectivePerspective fromfrom IMAGEIMAGE

Evolution of cultivated surfaceover Amazonia

Evolution boral forest surfacenorth of 70°N

same scenariodifferent climates

Same climateapplied to

different scénarios

The surface of cultures is determined mainly by demographic constrainsts and by theevolution of agricultural practices climate is a secondary factor

Natural vegetation evolves mainly under the action of climate but is a slow phenomenon possible retroactions at longer term than the century

Introduction

Method

Results

Conclusion

SynthesisSynthesis

Though this work does not show clear evidence of an impact offuture vegetation changes on climate, it brings some usefulinformations :

Shows the feasibility of the IMAGE2.2-GCM coupling

An impact on climate is found locally (important in term ofvariability)

But no important retroaction is found at the decennal timescale

weak impact of climate on modeling of cultures inside IMAGE

The century time-scale is somewhat short to detect theappearance of a retroaction between natural vegetation changeand climate

Introduction

Method

Results

Conclusion

Future perspectivesFuture perspectives

Remarks :

To simulate only the natural evolution of vegetation is not realistic(the evolution of cultivated surfaces is very important)

The evolution of the surface of cultures depends mainly on thechosen economic scenario

Proposition :

Use of projections of land-use produced by IMAGE (or other impactAssessment Models) for each scenario directly in GCMs, in additionto simulations of natural vegetation dynamic vegetation models.

Introduction

Method

Results

Conclusion