The Global Gridded Crop Model

Intercomparison – Approaches, insights and caveats of modeling

climate change impacts on agriculture at the

global scale.

Christoph Müller, Joshua Elliott

& the Ag-GRID team

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Climate, Agriculture, Markets

Nelson et al. 2013

Consumer

preferences

Population

GDP

Market

flexibility

Planting

dates

Varieties

Fertilizers

Irrigation

Crop mix

GHG

GCM

bias-

correction

interpolation

Modeling choices

www.ISI-MIP.org

www.isimip.org

www.AgMIP.org

Rosenzweig et al. 2013a

ISI-AgMIP fasttrack

• 7 GGCMs – EPIC, GEPIC, IMAGE-AEZ, LPJ-GUESS, LPJmL,

pDSSAT, PEGASUS

• ~500 scenarios – 5GCM * 4 RCP * 2 irrig * 2 CO2 *7GGCM

• 3-16 crops

• Rainfed & fully irrigated

• With and without CO2 fertilization

• 67420 locations (0.5°*0.5° grid)

Rosenzweig et al. 2013b

IPCC AR4 update for AR5

Rosenzweig et al. 2013b

IPCC AR4 update for AR5

Rosenzweig et al. 2013b

CO2 fertilization

Deryng et al. under review;

Rosenzweig et al. 2013b

Water consumption

Deryng et al. under review

Elliott et al. 2013

Indirect impacts

ISI-MIP: Constraints and potentials of future irrigation

water availability on agricultural production under

climate change (Elliot et al., under review)

Elliott et al. 2013

Limits to adaptation

Waha et al. 2013

Adapted sowing dates

Adapted cropping sequence

kcal/ha

Adaptation options

Piontek et al. 2013

Adaptation challenges

Piontek et al. 2013

Adaptation challenges

Nelson et al. 2013

Economic response

Spatial patterns

Müller & Robertson 2014

IMPACT DSSAT EPIC LPJmL pDSSAT PEGASUS

Maize Maize Maize Maize Maize Maize

Millet Maize ** Sorghum Millet *** ****

Rice Rice Rice Rice Rice ****

Sorghum Maize ** Sorghum Millet *** ****

Wheat Wheat Wheat Wheat Wheat Wheat

… … … … … …

Sub-tropical fruit * * * *** ****

Sugar beet * * Sugar beet *** ****

Sugar cane Maize Sugar cane Sugar cane *** ****

Sweet potatoes * * * *** ****

Temperate fruit * * * *** ****

Vegetables * * * *** ****

Other crops * * * *** ****

Commodity mapping

Nelson et al. 2013

Nelson et al. 2014

Commodity mapping effects

Schmitz et al. 2012

Externalities

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Schmitz et al. 2012

Externalities

Ag-GRID

• Organizing hub for gridded crop modeling and data within AgMIP.

• Includes >18 modeling groups so far and >10 data partners

• Helps coordinate global and regional multi-model assessments.

• Synthesis platform for AgMIP data, expertise, IT, etc.

• GGCMI: flagship project of Ag-GRID

• 3 distinct model types: 1) Gridded process models, 2) Dynamic global vegetation and land-surface models, 3) Empirical/process model hybrids

22

• Nine reanalysis-based historical weather

products spanning 1948-2012

• Harmonized on fertilizer, sowing, maturity, etc.

• Additional focus on large-scale

extreme drought/heat events in

the historical record.

Phase I: Historical evaluation

• Phase II: CTWN

– Multi-dimensional sensitivity study of model response

to carbon, temperature, water, and nitrogen.

• Phase III: Coordinated assessment

– Vulnerabilities, impacts, and adaptations

– New set of future climate forcings from CMIP5 and

CORDEX

– Detailed set of adaptation scenarios developed in the

AgMIP Representative Agricultural Pathways (RAPs)

framework

Future phases

Thanks