Outside the Box - Charlotte Kendra G. CastilloPurdue University Purdue Climate Change Research...

8/14/2019 Outside the Box - Charlotte Kendra G. Castillo Purdue University Purdue Climate Change Research Center

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THINKING OUTSIDE THECARBON BOX:

Science and Policy Issues of

Tropical Deforestation-Climate Feedbacks

Charlotte Kendra G. CastilloPurdue University

Purdue Climate Change Research Center

In cooperation withThe Manila Observatory (MO)

World Agro-forestry Centre (ICRAF)


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Reducing Emissionsfrom Deforestation andDegradation (REDD) -

Only half thepicture?


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om ne ma e an ar on- yc eEffects on

Large-scale Deforestation(Bala et al. PNAS Vol. 14, No. 6, 17 April 2007)

Global deforestation: 1113 ppmv CO2(vs. 732 ppmv in Standard) but cooler by~0.3K.

Combined carbon cycle and biophysicaleffects of deforestation in differentregions:

Tropical Temperate Boreal

net warming of +0.7K near-zero temperaturechange of -0.04K net cooling of -0.8K

+199 ppmv CO2 +110 ppmv CO2 +5 ppmv CO2

422 PgC released 316 PgC released 80 PgC released


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The Whole Picture


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Impacts of Deforestation

WARMING:

Adding CO2 to

atmosphere

Eliminating possible

carbon storage in trees Decreasing

evapotranspiration triggers changes inwater vapor, clouds,

lapse rates which affectlocal and globaltemperature changes.

COOLING:

Increasing surfacealbedo, thusdecreasing radiation

absorbed at surface.


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Carbon Cycle Effects

Manifested globally

Lag between cause andeffect

Justification forpromoting

reforestation/afforestation

Biophysical Effects

Most strongly felt atregional scales; needmore research toestablish

teleconnections.

Instant impact (e.g.albedo)

Not considered inpolicy

How do we weigh/trade off impacts of different

scales in climate policy???


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Gaps in currentresearch: Deforestation applied

unrealistically in models

Rates and spatial patterns may

matter given integration ofbiogeophysics with carbon cycle.

No common metrics.

Crucial also from a policy

standpoint. Human dimension not yet

coupled to earth system models.


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Research Objectives

Full earth system integration usingCommunity Climate System Modelver.4 (atm, lnd, ice, ocn)

More realistic deforestation via annual

forcing Analyze sensitivity of transitional

and equilibrium climate to differentdeforestation pathways (rate +preservation target)


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PHASE 2

Development Socio-economicOptimization Schemes for

Forest Preservation vs.Deforestation-for-Agriculture

Decisions.

Integration of Socio-EconomicScheme into Climate Systemand Modeling Feedbacks and

Impacts.

Policy Implications ofIntegrated Modeling

PHASE 3

Coupled Physical SystemSensitivity Analysis:Sensitivity to PreservationTargetSensitivity to Deforestation

RatesSensitivity to Spatial PatternsSensitivity to Region

Policy Implications ofSensitivity Analysis

PHASE 1

Offline Biosphere SensitivityAnalysis:Sensitivity to PreservationTargetSensitivity to Deforestation

RatesSensitivity to Spatial PatternsSensitivity to Region Research Flow


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CCSM3 Reflects impact of biophysics on

climate

+Dynamic Global Veg Model(DGVM)

Contrast sensitivity to 10% vs.1% annual deforestation rate.

10% preservation target.

Applied across tropical band(30deg S to 30degN).

Preliminary Fully-Coupled Results


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10% Annual Deforestation

Continue reapingeconomic benefits (for~20 years untilpreservation target is

hit).

Deforestation ceasessooner. Land cover

and climate alsostabilize sooner.

1% Annual Deforestation

Upfront costs requiredto slow deforestation.

Deforestation

continues longer(~70-80 years) thoughat a slower rate.

Both scenarios have the same preservation target

but will the transitional climate differ?


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SE Asia

COOLING?


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SE Asia

WARMING?


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10%

10%control

control

1%

1%


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control

control

10%

10%

1%

1%


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Preliminary Findings

How a preservation target isreached may be asimportant as the targetitself.

Effect of pathways moredistinguishable regionally

In SURFACE TEMPs In MOISTURE fluxes.


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Biophysics vs. biophysics

Increase in albedo vs. decreasein latent heat flux

Biogeochemistry vs.biogeochemistry

Transient increase inphotosynthetic uptake due tograsses vs. loss of carbonstocks from mature trees


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However, full interactionbetween biophysics andcarbon cycle still uncertain

biosphere-atmosphere Cfluxes not captured.



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Both adaptation and mitigation effortsneed to be informed bycomprehensive, fully-coupled modelingof the earth system leading to

desired/prescribed scenarios.

Do we need a climate effectivenessindex?


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Future Work

Integrate with socio-economic module

CCSM4 +DGVM

Economic agentoptimization

module(rapid response)

Generalequilibrium model(slow response)

x-yearclimateaverages

Land coverdecisions

Annualclimatedata

Adjustments


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THANK YOU!

Acknowledgements Kevin Robert Gurney1,3 , Matt Huber1,3 , Gerald Shively2,3

1Department of Earth & Atmospheric Sciences, PurdueUniversity;2

Department of Agricultural Economics, Purdue University3Purdue Climate Change Research Center (PCCRC)

Manila Observatory

World Agroforestry Center (ICRAF), Philippines

Outside the Box - Charlotte Kendra G. CastilloPurdue University Purdue Climate Change Research...

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Transcript of Outside the Box - Charlotte Kendra G. CastilloPurdue University Purdue Climate Change Research...