Direct Climate Impacts of Commercial Agricultural Expansion

Michael T Coe

The Woods Hole Research Center

Commercial Agriculture in Tropical Environments Third Annual International Food Security Symposium

University of Illinois April 4, 2017

Global meat demand

Global soy Imports

• Increasing global demand for meat• Drives increasing meat and grain production for feed• Brazil has been at fore-front of this expansion

Corn

Soy

20012001

Corn

Soy

20132011

Soy and Corn exports from Mato Grosso

Cumulative deforestation

Cumulative deforestation

650

700

750

800

850

2004 2008 2012 2016

Year

Cu

mu

lative

lo

ss (

tho

usa

nd k

m2)

BiomeAmazonCerrado

How are forests important for the climate system?

Forests important for carbon balance and climate• ~ 15% of all CO2 put into atmosphere is from deforestation• Ending deforestation keeps CO2 out of atmosphere• Reforestation takes excess CO2 from atmosphere

Forests also have very direct affect on regional climate• Recycle water to atmosphere• Maintain low surface albedo and high net radiation• Support high convective activity and rainfall particularly at

beginning and end of wet season

Incoming precipitation and net

radiation

Precip = ET + R

Rnet = ET + H

Vegetation is a key part of the

transfer of energy and water back

to atmosphere

Coe et al., 2016; Panday et al,. 2015; Silverio et al., 2015

Coe et al., 2016; Panday et al,. 2015; Silverio et al., 2015

Coe et al., 2016; Panday et al,. 2015; Silverio et al., 2015

Coe et al., 2016; Panday et al,. 2015; Silverio et al., 2015

Spracklen and Garcia-Carreras, 2015; Costa et al., subm.

Xingu

MaToPiBa

Upper Xingu

176,000 km2 area

Forested indigenous reserve surrounded by mosaic landscape.

Compared values of evapotranspiration and land surface temperature from MODIS for native vegetation, crops and pastures, for period 2002-2013

Silverio et al., 2015

Maybe use

Intact forests send about about 3/4 of incoming solar radiation and precipitation back to atmosphere

• Equivalent to ~1300 mm/yr or ~100 W/m2

• Throughout much of long dry season

Panday et al.,2015; Silverio et al., 2015

Soy and pasture evapotranspireat the same rates as forest during growing season

Silverio et al., 2015

But not during the dry season• Water is trapped in soil

because there are no active roots

• Annual evapotranspiration reduced by ~25-30% (pasture and soy respectively)

• Sensible heat increased 6-10%

• Rnet decreased by 12-18%• Land surface temperature 4-

6.5°C hotter than the forest

Soy and pasture evapotranspireat the same rates as forest during growing season

Silverio et al., 2015

Upper Xingu

Surface Temperature outside reserve is 3C warmer and increasing

Silverio et al., 2015

Upper Xingu

Flux of water to atmosphere decreased by 6%

Silverio et al., 2015

• 2 million ha brought into mechanized agriculture in MaToPiBa region from 2002-2013

• 75% in native Cerrado, remainder from existing pastures

• 10-15km3/yr less evapotranspiration over that decade (~-3%)

2001 2013

Agricultural expansion in Cerrado

Spera et al. 2016

• Government projections are for an additional nearly 3 million ha of crop expansion in this region

• Equals an additional evapotranspiration decrease of about 4.5km3

Spera et al. 2016

2001

Agricultural expansion in Cerrado

Eva et al., 2003

Present day

2050 with

governance

Soares-Filho et al., 2006

2050 business

as usual

Soares-Filho et a., 2006

Modeling Land Surface Processes and

Atmospheric Feedbacks

Are future atmospheric feedbacks to

rainfall of potentially important scale?

What are consequences for ecosystem

services?

Coe et al., 2009, Oliveira et al., 2013, Stickler et al., 2013

BAU 2050

Regional rainfall

decrease of 15%

Coe et al., 2009

Xingu

Tocantins

Rainfall decrease has

consequences for

ecosystem services

30% decrease in crop

yield in both basins

30% decrease in

power potential of

Xingu

Oliveira et al., 2013

Stickler et al., 2013

Xingu

Tocantins

Conclusions:

• Deforestation fundamentally shifts energy/water balance (ET, dS, Q, Rnet, H, T).

• Large areas of Cerrado and Amazon have been deforested – measurable changes to energy and water balance have occurred.

• Deforestation continues both, legal and illegal.• Deforestation is consistent with recent observed

changes in rainfall at end of dry season.• Future climate and productivity of the region will

depend on how much deforestation rates can be curbed or reversed.