Climate and Economic Drivers of Land Use Change

http://globalchange.mit.edu/

John Reilly, Niven Winchester, Adam Schlosser, Qudsia Ejaz

MIT Joint Program on the Science and Policy of Global ChangeMassachusetts Institute of Technology

Questions or comments?Contact: John Reilly

jreilly@mit.edu

North American Carbon Cycle Meeting,Albuquerque, New Mexico4-6 Feb., 2013

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• Population and Income Growth—greater demand, changing consumption patterns—more meat, more land.

• Agricultural productivity growth—more food on less land.• Price driven intensification of production—pasture to feedlots,

dry-land to irrigated, more fertilizer, low value to high value• Climate: Wetter in dry climates, drier in wet climates, or vice

versa, warmer in cold climates, warmer in hot climates• Atmospheric composition: CO2 and crop increase but also

weeds; ozone—damage; nitrogen deposition.• Energy and Climate Policy: higher energy prices, higher

fertilizer and energy costs for agriculture, costs of reducing methane from rice and livestock, nitrous oxide from use of fertilizers

• Land policy: Carbon sequestration/reforestation, forest protection

Drivers

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MIT EPPA, 16 Region, multiSector CGE model

Downscaling Technique/ Spatial disaggregation algorithm

DYNAMICTERRESTRIAL ECOSYSTEMSMODEL (TEM)

CH4, N2O, Net CO2

from land useCrop, pasture, bioenergy, forestproductivity

Spatial data (0.5º x 0.5º) forland use

Economy-Global Land System Interactions

GHG and Other Pollutantsfrom energy and agriculture/land use

Land use shares for crops, livestock, bioenergy, forestry

CO2, Tropospheric Ozone, Nitrogen depositionTemperature, Precipitation,

Solar Radiation

Coupled Ocean, Atmosphere

Biogeophysical Land Processes

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Climate, CO2 Concentrations, and Changes in Land Carbon Storage• Land policy gets us another ½ degree of avoided warming.• Not much difference between the no biofuels and biofuels policy. • With land incentives, land is a major sink.• The climate policy also helps largely because we need less land for

crops because of less environmental (ozone) damage.

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Energy Results• Energy-Only: All

liquid fuels from biomass, large reduction in use, coal w/CCS

• Energy+Land: Less biofuels, some petroleum, less use.

• No-biofuels: similar, more petroleum

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Land Use

• Main difference in Energy only from No-Policy is more land biofuels, less to cropland.

• Reason is mostly less damage to crops from ozone.

• With Energy+Land significant reforestation, with biofuels further push into crop and pasture land.

• This at cost of higher commodity prices.

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Regional patterns of change in land carbon

Much loss, especially Africa, Asia

Mostly gain

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Big Effects on Food Prices When Land Carbon priced

Solid: no-policy Short Dash: Energy-OnlyDots: No biofuels Long Dash:Energy+ Land

Surprising result:No-policy and energy only about the same.

Less environmental damage w/ energy policy, but higher energy and GHG control costs offset benefit to crops.

Energy+Land has big price impacts. w/o biofuels some pressure off.

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Summary• This is a complex system with many interactions

Climate policy affects climate/atmospheric compositionWhich affects crop/forest/pasture productivityAnd, energy and fertilizer inputsAnd, costs of controlling methane and nitrous oxide

It also affects incomes and food prices.

And these determine both the amount of land used and where crops are grown.

Biofuels and land carbon sequestration are still another element.

• Understanding these linkages is critical to designing policies that don’t have unpleasant surprises.

Data and models well calibrated to data are needed. Models must represent physical processes and economic/social response that will occur through markets and policy