Courtesy IIASA

FEEDING A HOT AND HUNGRY PLANETTim Searchinger

(Princeton University, German Marshall Fund of the U.S.tsearchi@princeton.edu

Ag’s Contribution to World Greenhouse Gases ~ 30%

(IPCC 2007; Bellarby 2008 , in CO2 eq.)

• Nitrous oxide – fertilizer, livestock deposits, biomass burning

• Methane – livestock (enteric), cows, rice, manure, biomass burning

• Energy – farm machinery, fertilizer, irrigation pumps

• 13 million hectares/yr gross deforestation

• N20 and NH4 to grow 60% by 2030

Non-Ag33.5 Gt

69%

Ag Land Expansion

8.5Gt17%

CO2 from Energy

Use1 Gt2% N2O and

NH46 Gt12%

2004

49 Gt Total

- 16% of world malnourished- 1/3 of children in developing world stunted- 30 million babies born impaired due to lack of natal nutrition - 5 million children die annually from causes related to lack of nutrition

19501952

19541956

19581960

19621964

19661968

19701972

19741976

19781980

19821984

19861988

19901992

19941996

19982000

20022004

20062008

$0

$2

$4

$6

$8

$10

$12

$14 Trends in Cereal Crop Prices, United States Season Average

BarleyCornOatsSorghumWheat

Seas

on a

vera

ge p

rice

, $/b

ushe

l 2000 Constant $

Source: USDA, NASS

Undernourished People and Recent Changes

Source: FAO. 2009. The State of Food Insecurity In the World, 2008

Agriculture Mitigation Potential at $100/t(IPPC 2007 Mitigation Report)

The Challenge of Soil Carbon Gains

• No Till– Depth

• Baker et al., Agriculture Ecosystems and Env. 118:1-5 (2007); • Blanco-Canqui & Lal, SSSAJ 72:693-701 (2008)

– Nitrous Oxide• Africa• Are we actually losing soil carbon?

– UK, Midwest– New Zealand

Biochar?

Conventional approach But . . . Land grows plants

(carbon) anyway* forest* food

Only ADDITIONAL plant growth helps

Biofuels & Greenhouse Gases

Large Bioenergy Potential Studies

• Most potential arable land – IPCC 2007 chapter 8 - 1.3billion hectares and/or

• All forest growth in excess of harvest (Smeets 2008)and/or

• All “abandoned” cropland (Hoodwijk (2004) and/or

• Hundreds of millions of hectares of “grazing” or “other” land – savannah (Fischer 2001; Smith 2007)

Recounts existing forest, forest re-growth, net terrestrial carbon sink, land counted for grazing

Unused Cropland is Mostly Wetter Savannah, Woodlots and Forest in Latin

America and Africa

Other Uses of Land?

• More cropland and pasture for food –200-500 million hectares by 2050

• Terrestrial carbon sink – 9.5 GT CO2/yr• Avoided deforestation potential – 9 Gt/year• Afforestation mitigation potential – 4 Gt/year• Restore peatlands – 1.3 gigatons/year

All from IPCC 2007 Mitigation Report, chapters 8 & 9

IPCC Baselines – Mission Accomplished? IPCC SRES Scenarios

Predicted Emissions from Land Use Change Gigatons C

Year B-1 B-2

2020 2.2 0

2050 -0.4 -0.2

Foley J A et al. PNAS 2007;104:12585-12586

©2007 by National Academy of Sciences

Croplands

Grazing lands

Can We Avoid Land Use Change for Food?

Agriculture occupies 35% of ice free surface

19651967

19691971

19731975

19771979

19811983

19851987

19891991

19931995

19971999

20012003

20050

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

World Cereal Yield Growth 1965-2006

5 year average percent change in cereal WorldLinear (5 year average percent change in cereal World)5 year average percent change in Population WorldLinear (5 year average percent change in Population World)

5 ye

ar a

vera

ge a

nnua

l cha

nge

, per

cent

Carbon Dioxide Emissions – Reilly (MIT) – Impact of Ozone

Note: Emissions from land use change are those from projected changes. Continuing uptake from forest regrowth from pre-2000 land use change and changed uptake (due to CO2/climate) on undisturbed land is not shown.

No-policy scenario

Reference

-100

102030405060708090

2010 2040 2070 2100Year

CO2

emis

sion

s (b

mt)

Land All other Total

Change in average maximum temperature ( oC), 2000–2050top is CSIRO; bottom is NCAR

Impacts on Yields of Climate Change Itself

Nelson et al., Climate Change Impact on Agriculture (IFPRI 2009)

With no crop fertilization effect , by 2050:–Rice yields decline by 14 – 18% in developing countries- Irrigated wheat declines 28-34%

Areas of Water Stress (IIASA)

Optimism: Yields Gaps

Courtesy of Pedro Sanchez

also:* Much food waste* Biotechnology•Livestock intensification opportunities

•FAO’s latest estimate ~120 million hectares additional cropland by 2050

Natural Forest

Natural Forest (Melillo, Gurgel, et al. 2008)

Natural Forest (“Deforestation” Scenario)

Natural Forest

Land Lessons

• Land is limited

• MORE CARBON NOT DIFFERENT CARBON

• Understand land/input tradeoffs

Important question: where isthe underutilized “other” land

• Carbon content• Outputs• Biodiversity• Ownership• Barriers to use

Peatland Restoration – 1.3 Gt/y (IPCC 2007 Mitigation)

70% of rice straw in Punjab burned Punia, Current Science 94:1185-1190 (2008)

Predicted 2000-2010 Pasture & Cropland Expansion in Latin America

Wassenaar et al., Global Env. Change 17:86-104 (2007)

Two thirds of net agricultural expansion is pasture

Sources of Nitrous Oxide

EPA 2006 Davidson 2009 Crutzen

Manure & Fertilizer

4.4 soils0.4 manure management

2.2 Fertilizer2.8 Manure

4.3-5.8

Adapted from Davidson, Nature Geoscience 2:659-662 (2009)

Role of Livestock in Methane and Nitrous Oxide Emissions

Gas Source Mainly Mainly Percentagerelated to related to contributionextensive intensive to totalsystems systems animal food

(109 tonnes CO2 eq.)

(109 tonnes CO2 eq.) GHG emissions

CH4 Total anthropogenic CO2 emissions 5.9

Total from livestock activities 2.2

enteric fermentation 1.6 0.2 25

manure management 0.17 0.2 5.2

N2O Total anthropogenic CO2 emissions 3.4 Total from livestock activities 2.2

N fertilizer application ~ 0.1 1.4

indirect fertilizer emission ~ 0.1 1.4

leguminous feed cropping ~ 0.2 2.8manure management 0.24 0.09 4.6manure application/deposition 0.67 0.17 12indirect manure emission ~ 0.48 ~ 0.14 8.7

Steinfeld et al. 2007, Livestock’s Long Shadow (FAO)

Land Use Original Net Primary Productivity

Actual Net Primary Productivity

Human Appropriated Percentage

Cropland 611 397 83.5%

Grazing Land 486 433 19.4%

Forestry 720 720 6.6%

Haberl et al., PNAS 104:12942-12947

World Grazing Land

Contrast FAO Grazing Land NPP World - 1047

Rangeland Thoughts

• Possible Pursuit: Productivity enhancement plus forest regeneration

Better UnderstandingChallenges of Lifecycle Analysis for Livestock

(source Theun Vellinga, Wageninen University)

• Reasonable data available– Kilograms of meat, milk, slaughtered animals– Total numbers of animals– Total fertilizer input on country level

• No systematic data available– herd demography– feed use– pasture quality– feed production – and manure management

Doberman, Cassman, Ser. C Life Sciences 48:745-758 (2005)

Deep Placed Urea SupergranulesIFDC

17-33% yield gains, decreases urea by 33%

Comparison of USG with Urea using Farmer's Practice

N Applied (kg N ha-1)

0 20 40 60 80 100 120 140 160 180

Ric

e G

rain

Yie

ld (

kg h

a-1)

1200

16002000

24002800

32003600

400044004800

52005600

60006400

68007200

760080008400

Urea (IFDC, 2000-5) USG (IFDC, 2000-5)Urea (IRRI, Bangladesh)USG (IRRI, Bangladesh)

Technological Policy Development Basic research

Rice High yielding upland or drier rice varieties

Technical and economic barriers to mid-season drainage outside of China

Cheap water management measures

•Measuring real NH4 and N20 effects; • Study controlling microbiology

Crop fertilization

*New fertilizer technologies;*Improved nitrification inhibitors; *Improved crop nitrogen use efficiencies

*Assessing existing fertilizer type use and trends in many areas;*Assessing barriers to adopting newer practices

*Widespread farmer testing of reduced or split season fertilizer application; *Cheaper tests; *New harvesting technologies for tree inter-cropping;*Testing new fertilizers

•Factors that control N availability•Assessing N20 effects in the field; *Tools for assessing land/input tradeoffs

Technological Policy Development Basic research

Livestock VaccineFood additivesNitrification inhibitorsManure reprocessing technologies

*Better understanding of livestock systems*Technological and economic opportunities for improved pasture efficiency

Livestock breeds;Aquaculture development;Improved digesters

Basic understanding of livestock systems, forage quality

Food waste Careful assessments of true storage obstacles

Factors that lead to food waste in developed countries

and now a brief advertisement . . .

Final Thoughts• “All” is beautiful

– Seek copper bullets– Don’t forget the “D” of R&D

• Practical/strategic approach– Coordinating teams– Scrutinize the teams

• Constantly question & improve numbers & make real field assessments

• Mix technology, policy, development & basic research• Give rangeland the respect it deserves• Immediate Policies That Can’t Wait

– Integrate REDD/food production– Develop NAMA guidance