1 Use of Cropland for Biofuels Increases Greenhouse Gas Emissions Through Land Use Change Tim...

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Use of Cropland for Biofuels Increases Use of Cropland for Biofuels Increases Greenhouse Gas Emissions Through Greenhouse Gas Emissions Through

Land Use ChangeLand Use Change Tim Searchinger, Ralph Heimlich, R.A. Tim Searchinger, Ralph Heimlich, R.A.

Houghton, Fenxia Dong, Amani Elobeid, Houghton, Fenxia Dong, Amani Elobeid, Jacinto Fabiosa, Simla Tokgoz, Dermot Jacinto Fabiosa, Simla Tokgoz, Dermot

Hayes, Tun-Hsiang Yu Hayes, Tun-Hsiang Yu

(tsearchi@princeton.edu)(tsearchi@princeton.edu)

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Nearly All StudiesNearly All StudiesHave Left Out Emissions from Have Left Out Emissions from

Land Use ChangeLand Use Change►Farrell et al, Science:Farrell et al, Science:

““Significantly greater use of biofuels might shift Significantly greater use of biofuels might shift marginal or unused lands into crop production, marginal or unused lands into crop production, however, potentially resulting in significant changes in however, potentially resulting in significant changes in net GHG [greenhouse gas] emissions due to land use net GHG [greenhouse gas] emissions due to land use changes alone. . . . none of which are considered in the changes alone. . . . none of which are considered in the studies evaluated here. For these reasons, we ignore studies evaluated here. For these reasons, we ignore GHG emissions due to potential changes in land use.”GHG emissions due to potential changes in land use.”

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EU AnalysisEU Analysis

Commission of the European Communities, Commission Staff Commission of the European Communities, Commission Staff Working Document Biofuels Progress Report, Report on the Working Document Biofuels Progress Report, Report on the Progress Made in the Use of Biofuels and Other Renewable Progress Made in the Use of Biofuels and Other Renewable Fuels in the Member States of the European Union (10.1.2007) Fuels in the Member States of the European Union (10.1.2007)

"The JEC data do not take account the effect of land use "The JEC data do not take account the effect of land use change, notably changes in soil and plant carbon stocks. In the change, notably changes in soil and plant carbon stocks. In the absence of a global land use model, absence of a global land use model, it has not been possible to it has not been possible to estimate the greenhouse gas effect of the land use changes estimate the greenhouse gas effect of the land use changes likely to be associated with these scenarioslikely to be associated with these scenarios." ."

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Land Conversion Means All Land Conversion Means All Foregone Storage and Ongoing Foregone Storage and Ongoing

SequestrationSequestrationEmission from Land Emission from Land Use ChangeUse Change

► Release of carbon Release of carbon stored in plants and soil stored in plants and soil when forest and when forest and grassland is plowed up grassland is plowed up directly or directly or indirectly indirectly

Foregone ongoing Foregone ongoing sequestration sequestration

► Foregone annual, Foregone annual, ongoing carbon ongoing carbon sequestration on sequestration on former grassland and former grassland and forest that was forest that was converted or on converted or on croplands that would croplands that would revert to grassland or revert to grassland or forest absent biofuel forest absent biofuel demanddemand

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INDIRECT EFFECTS OBVIOUS AT INDIRECT EFFECTS OBVIOUS AT LARGER ETHANOL NUMBERSLARGER ETHANOL NUMBERS

►31 billion gallons of corn ethanol in U.S. 31 billion gallons of corn ethanol in U.S. in 2015 would mean 74 million acres of in 2015 would mean 74 million acres of corn for ethanol, equivalent to entire corn for ethanol, equivalent to entire U.S. corn grain crop in 2004U.S. corn grain crop in 2004

►Would greatly increase grain prices in Would greatly increase grain prices in long run – short run price rises even long run – short run price rises even largerlarger

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Indirect Effect Occurs Through Indirect Effect Occurs Through PricePrice

► Morton et al, Cropland Expansion Changes Deforestation Morton et al, Cropland Expansion Changes Deforestation Dynamics in the southern Brazilian Amazon, PNAS Dynamics in the southern Brazilian Amazon, PNAS 103(39):14637-41 – showing rate of deforestation increases 103(39):14637-41 – showing rate of deforestation increases with pricewith price

► Crop expansion also pushes grazers into converting forest Crop expansion also pushes grazers into converting forest

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Price Effect is Rapid Because Transformed Into Land Value Appreciation

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Feedstock Credit is Critical to Feedstock Credit is Critical to Findings of Greenhouse Gas Findings of Greenhouse Gas

BenefitsBenefits

Source of Fuel*

Making

Feed stock

Refining Fuel

Vehicle Operation (Burning

Fuel)

Net Land Use Effects

% Change in Net

GHGs vs. Gasoline

Feedstock Uptake

from Atmosph

ere(GREET)

Land Use

Change

Total GHGs

Gasoline+4 +15 +72 0 – +92 –

Corn Ethanol (GREET)

+24 

+40 

+71 

-62 

–

+74 -20%

+135

without

feedstock

credit

+47% without

feedstock credit

Greenhouse gasses (CO2) per mega joule of fuel

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Why a feedstock credit?Why a feedstock credit?

►Land already existsLand already exists►Forests and GrasslandForests and Grassland

Have stored carbon for decades and may Have stored carbon for decades and may continue to sequester carboncontinue to sequester carbon

►Cropland produces carbon benefit in Cropland produces carbon benefit in form of protein, carbohydrates, fats. form of protein, carbohydrates, fats. If we use cropland for fuel, we have to If we use cropland for fuel, we have to

find our carbon elsewhere, displacing find our carbon elsewhere, displacing carbon storagecarbon storage

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Feedstock Credit Without Land Use Feedstock Credit Without Land Use Change Is One Sided Accounting of Land Change Is One Sided Accounting of Land

Use EffectUse EffectBiofuel can only justify atmospheric credit if:Biofuel can only justify atmospheric credit if:

(1) growing feedstock for biofuel causes a NET (1) growing feedstock for biofuel causes a NET INCREASE in carbon removed by land overall, orINCREASE in carbon removed by land overall, or

(2) the biofuel uses material that would (2) the biofuel uses material that would otherwise return to the atmosphere anyway without otherwise return to the atmosphere anyway without doing work. doing work.

Land use change emissions are necessary to Land use change emissions are necessary to calculate the net atmospheric credit or debtcalculate the net atmospheric credit or debt

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Using Cropland to Produce Biofuels Using Cropland to Produce Biofuels Will Cause Large Increases in Will Cause Large Increases in

Greenhouse Gasses from Land Use Greenhouse Gasses from Land Use Change Change ► Most diverted grain will be replaced (even after crediting biofuel Most diverted grain will be replaced (even after crediting biofuel

feed by-products)feed by-products)► Breaking out cropland is cost-effective way of meeting new Breaking out cropland is cost-effective way of meeting new

demanddemand► Losses on any forest or grassland converted to cropland are high Losses on any forest or grassland converted to cropland are high

compared to annual gains per hectare of biofuel: compared to annual gains per hectare of biofuel:

Corn-based ethanol (2015)Corn-based ethanol (2015) 1.8 tonnes/hectare/year gain 1.8 tonnes/hectare/year gain (GHG Co2 eqv.) (by comparison (GHG Co2 eqv.) (by comparison

with using gasoline)with using gasoline)

Switchgrass (2015)Switchgrass (2015) 8.6 tonnes/hectare/year gain8.6 tonnes/hectare/year gain

versusversus

Forest conversion Forest conversion 604-1146 tonnes/hectare loss + ongoing 604-1146 tonnes/hectare loss + ongoing sequestrationsequestration

Grassland conversion Grassland conversion 75 – 305 tonnes/hectare loss (+ displaced 75 – 305 tonnes/hectare loss (+ displaced grass grass feed)feed)

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Our Analysis for Corn EthanolOur Analysis for Corn Ethanol

► Integrates 3 modelsIntegrates 3 models GREETGREET CARD Agricultural ModelCARD Agricultural Model Houghton land use change for 1990sHoughton land use change for 1990s

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ConceptuallyConceptually

► DDG’s offset diverted corn –1/3 of feed comes backDDG’s offset diverted corn –1/3 of feed comes back► Higher price lowers demand but modestly Higher price lowers demand but modestly ► Some grain made up by higher yields – CARD Some grain made up by higher yields – CARD

assumes no net effectassumes no net effect Rising yields from increased investment offset by Rising yields from increased investment offset by

use of more marginal land and less rotation use of more marginal land and less rotation ► Significantly more acres abroad required to offset Significantly more acres abroad required to offset

diverted domestic corn acres because of lower diverted domestic corn acres because of lower yieldsyields

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Effects of 14.8 Billion Gallon Effects of 14.8 Billion Gallon Increase in 2015/16Increase in 2015/16

►31.9 million acre diversion of corn 31.9 million acre diversion of corn acres to ethanolacres to ethanol

►Large rise in long-term grain prices Large rise in long-term grain prices (Corn from $3.16/bushel to (Corn from $3.16/bushel to $4.43/bushel, soybeans from $6.56 to $4.43/bushel, soybeans from $6.56 to $8.07, wheat $4.29 to $5.27)$8.07, wheat $4.29 to $5.27)

►Huge Export DeclinesHuge Export Declines 63% corn, 33% soybeans; 53% wheat; 63% corn, 33% soybeans; 53% wheat;

21% pork; 15% chickens21% pork; 15% chickens

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RESULTS – LAND CHANGE RESULTS – LAND CHANGE EFFECTS EFFECTS

12.8 million hectares of corn diverted12.8 million hectares of corn diverted

10.8 million hectare increase in 10.8 million hectare increase in cropland worldwidecropland worldwide

2.8 in2.8 in Brazil, 2.2 in U.S.; 2.3 in India and Brazil, 2.2 in U.S.; 2.3 in India and ChinaChina

Mix of forest, savannah and Mix of forest, savannah and grasslandgrassland

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Biodiversity EffectsBiodiversity Effects

The Cerrado – 10,000 plant species, 44% The Cerrado – 10,000 plant species, 44% found nowhere elsefound nowhere else

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Source of Fuel*

Making Feed stock

Refining Fuel

Vehicle Operation (Burning

Fuel)

Net Land Use Effects

% Change in Net GHGs vs.

Gasoline

Feedstock Uptake from Atmosphere

(GREET)

Land Use

ChangeTotal

GHGs*

Gasoline +4 +15 +72 0 – +92 –

Corn Ethanol (GREET)

+24 

+40 

+71 

-62 

–

+74 -20%

+135 without

feedstock credit

+47% without feedstock

credit

Corn Ethanol + Land Use Change +24 +40 +71 -62 +104 +177 +93%Biomass Ethanol (GREET) +10 +9 +71 -62 – +27 -70%

Biomass Ethanol + Land Use Change +10 +9 +71 -62 +111 +138 +50%

GREENHOUSE GAS RESULTS

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ResultsResults

►Corn ethanol nearly doubles emissions Corn ethanol nearly doubles emissions from driving over 30 years from driving over 30 years

►Corn ethanol pays back carbon debt Corn ethanol pays back carbon debt after 167 yearsafter 167 years

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SensitivitySensitivity

► If 20% of diverted grain replaced by If 20% of diverted grain replaced by increase in yields – 133 year paybackincrease in yields – 133 year payback

► If ethanol emissions savings, absent If ethanol emissions savings, absent land conversion, double -- 83 year land conversion, double -- 83 year payback payback

► If per acre land emissions from If per acre land emissions from conversion were half of our estimate – conversion were half of our estimate – 83 year payback83 year payback

► If all true – 34 year paybackIf all true – 34 year payback

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Biomass & SugarcaneBiomass & Sugarcane

► Biomass grown on soybean fields Biomass grown on soybean fields 70% reduction without land conversion (GREET)70% reduction without land conversion (GREET) 50% increase in emissions with land conversion50% increase in emissions with land conversion

► Brazilian sugarcane Brazilian sugarcane 85% reduction without land conversion (Macedo 85% reduction without land conversion (Macedo

et al.)et al.) 4 year payback period if conversion from 4 year payback period if conversion from

grassland, and 45 years if converted from grassland, and 45 years if converted from rainforest forest directly or indirectlyrainforest forest directly or indirectly

But it’s worth exploring solutions But it’s worth exploring solutions

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Factoring Land Use Change Into Factoring Land Use Change Into Soy BiodieselSoy Biodiesel

►Simpler Analysis – Assume decreased U.S. Simpler Analysis – Assume decreased U.S. production oil replaced proportionately by production oil replaced proportionately by major vegetable oil exporters major vegetable oil exporters

►20% decline in non-fuel demand, 20% of 20% decline in non-fuel demand, 20% of diversion replaced by yield increasesdiversion replaced by yield increases

►Result: Soy biodiesel, instead of 50% Result: Soy biodiesel, instead of 50% savings increases GHG emissions by savings increases GHG emissions by 158% increase compared to conventional 158% increase compared to conventional dieseldiesel

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What about surplus What about surplus cropland? cropland?

Truly surplus crops would regain forest or grass Truly surplus crops would regain forest or grass ►What we think of as surplus represents modest What we think of as surplus represents modest

excess during years of low prices, but prices fluctuateexcess during years of low prices, but prices fluctuate►There is no surplus, productive land from carbon There is no surplus, productive land from carbon

standpointstandpoint

Regional and international cropland is shifting Regional and international cropland is shifting and price accelerates Latin American expansionand price accelerates Latin American expansion

Growing worldwide demand anyway for richer Growing worldwide demand anyway for richer Asia and 9-10 billion peopleAsia and 9-10 billion people

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EU Directive?

Indirect effects the key, indirect Indirect effects the key, indirect effects are the key, indirect effects are the key, indirect effects . . . .effects . . . .

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Impacts on Food Impacts on Food Consumption Consumption

►Roughly 10% of diverted feed grains Roughly 10% of diverted feed grains for livestock and 6% of diverted feed for livestock and 6% of diverted feed grains for dairy not replaced because grains for dairy not replaced because of reduced meat and dairy of reduced meat and dairy consumption consumption

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Would Rules or Disincentives Against Would Rules or Disincentives Against All Land Conversion Eliminate All Land Conversion Eliminate

ProblemProblem

►Have to be very strong and universal Have to be very strong and universal ►Would constrain the cheapest sources Would constrain the cheapest sources

of new supply. Grain and meat prices of new supply. Grain and meat prices would rise dramatically for developing would rise dramatically for developing country poor country poor Much of greenhouse gas “benefit”Much of greenhouse gas “benefit”

would come from changed diets of poor would come from changed diets of poor

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Where Should We Focus Where Should We Focus

►Biofuels from waste products Biofuels from waste products

- biggest cheapest source- biggest cheapest source►Use of “marginal,” Use of “marginal,”

unproductive lands (maybe)unproductive lands (maybe)►Algae?Algae?►Fall harvests from reserveFall harvests from reserve

landslands

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Larger Context Larger Context

►Land use change 20% of CO2 Land use change 20% of CO2 EmissionsEmissions

►Need to reduce land use change while Need to reduce land use change while feeding billions more people eating feeding billions more people eating more meatmore meat

►Makes little sense to reduce fossil fuels Makes little sense to reduce fossil fuels at expense of greater land conversion at expense of greater land conversion