Agriculture & Climate Change: A three-fold relationship

I. Agriculture as a contributor to Climate Change

II. Impacts of Climate Change on Agriculture

III. Agriculture as a potential moderator of Climate Change

I. Agriculture as a part of the problem

30% of total global anthropogenic emissions of GHGs (Bowman 2001)

> ½ total global anthro. Emissions of CH4 and N2O

CH4: from rice & livestock production

N2O from fertilizers & manure Particulate matter & GHGs from land

clearance by fire & burning of residues

(Humane Society)

Source of 30% of total global anthropogenic emissions of GHGs

Particulate matter & GHGs from land clearance by fire & burning of residues

> ½ total global anthropogenic emissions of CH4 and N2O CH4: from rice & livestock

production N2O from fertilizers & manure

(FAO 2003, Gomiero et al. 2008)

laobumpkin.blogspot.com

www.dowagro.com

www.ncagr.gov

Particulate matter & GHGs from land clearance by fire & burning of residues

> ½ total global anthropogenic emissions of CH4 and N2O CH4: from rice & livestock

production N2O from fertilizers & manure

laobumpkin.blogspot.com

www.dowagro.com

www.ncagr.gov

Other sources:

CO2 emissions from Field work, machinery Production of fertilizers & pesticides

“Food miles” thought to be relatively minor source shifting <1 day/wk’s consumption of red meat to

other protein sources or vegetable-based diet = same impact as buying local

GHG emissions dominated by production phase = 83% of average US household’s 8.1 tons CO2/yr footprint for food consumption

(Gomiero et al. 2008, Niles et al. 2002, Weber & Matthews 2008)

II. Impacts of Climate Change on Agriculture

Direct impacts from temp/precip. changes, plus:

Increased variability in weather Extreme conditions Sea level rise & surge – inundating &

ruining coastal agricultural lands CO2 fertilization

(FAO 2003, IPCC 2008)

II. Impacts of Climate Change on Agriculture

Indirect impacts: Changing crop-weed competition dynamics Range changes of pests & pathogens

Expanded range predicted for many pathogens Less-cold winters allow increase in pests Different range changes between pests &

pathogens and natural controls Decreased biodiversity in natural

ecosystems (Patterson et al. 1999, FAO 2003, IPCC 2008)

III. Agriculture as part of the solution?

Increasing carbon sequestration through land management

Agroforestry Rotations with cover crops, green manure Conservation tillage

Could reduce global CO2 emissions by 5-15%

Organic farming (but limited benefits) Enhances carbon storage in soil

Biogas digesters?(Gomiero et al. 2008, FAO 2003, Niles et al. 2002)

Other solutions and adaptationsChanging inputs Biofuels Reduce agrochemicals

(e.g., N fertilizers) Reduce pumped irrigation and mechanical power Reduce high energy-consuming feedstuffs for

livestock Adapt: Selective breeding, GMOs

(Gomiero et al. 2008, FAO 2003, Niles et al. 2002)

Other solutions and adaptationsChanging Demand Switch from beef & dairy

to other proteins, veggies(Weber & Matthews 2008, FAO 2003)

Travel-eat-sleep.com

news.bbc.co.uk

www.cloudyday.org

Some Discussion Questions:

Do developed nations have an obligation to reduce their consumption of beef?

Biofuels are one of the recommended mitigation strategies in the FAO report… but how does this interact with concerns over food supply?

Do you see improved land management practices being implemented in reality? Why/why not?

Acknowledgements & ReferencesThanks to Alex Ruane for helpful suggestions

Agriculture & the environment: Changing pressures, solutions, and trade-offs. In: World Agriculture: Towards 2015/2030 – An FAO Perspective. Ed. Bruinsma, J

Climate change and agriculture: physical and human dimensions. 2003.  In: World Agriculture: Towards 2015/2030 – An FAO Perspective. Ed. Bruinsma, J

Easterling, W.E., et al. 2007: Food, fibre and forest products. Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, M.L. Parry, O.F. Canziani, J.P. Palutikof, P.J. van der Linden and C.E. Hanson, Eds., Cambridge University Press, Cambridge, UK, 273-313

Gomiero, T., et al. 2008. Energy and Environmental Issues in Organic and Conventional Agriculture, Critical Reviews in Plant Sciences,27(4),239-254

Niles, J.O., et al. 2002. Potential carbon mitigation and income in developing countries from changes in use and management of agricultural and forest lands. Phil. Trans. R. Soc. Lond. A, 360:1621-1639.

Patterson, D.T., et al. 1999. Weeds, insects, and diseases. Climatic Change, 43: 711-727.Weber, C., & Matthew, H.S. 2008. Food-miles and the relative climate impacts of food choices

in the United States. Environmental Science & Technology, 42: 3508-3513.