Global Warming Effects Around the World

Karnataka, India

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People (Food)

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Freshwater (Extreme Wet)

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Farm workers in India

Coffee production in India largely occurs on small, family-owned farms. A long-term increase in the number of extreme and unseasonal rainfall events has lowered crop yields, threatening the livelihood of Indian coffee workers.1

Key Facts

Coffee has been cultivated in the Karnataka state of India for more than 300 years,2 and today provides a livelihood for nearly 1.5 million families.5 However, coffee production has been declining as extreme rainfall events take their toll on crops.6,7

  • From 2002 to 2011, Indian coffee production declined by nearly 30 percent.6 Heavy crop losses in 2009 and 2010 have been attributed to heavy unseasonal rains.6,7
  • Maximum daily rainfall amounts in western India have been rising at a rate of 0.3 percent per year. About half of this increase is estimated to be attributable to emissions of heat-trapping gases—primarily from the burning of oil, trees, and gas.14
  • Mid-range scenarios22 for future emissions of heat-trapping gases project increases in both annual rainfall totals and the number of extreme rainfall events23 in India during this century.


Coffee has been cultivated in the Karnataka state of India for more than 300 years,2 and in 2010 India was the world's sixth-largest coffee producer.3 Some 70 percent of Indian coffee production takes place on small farms of less than 10 hectares (2.5 acres).4 Coffee is an important source of economic sustenance for the people of India: it provides a livelihood for nearly 1.5 million families.5 In recent years, however, coffee production has been declining as changes in climate affect crops. 6,7

In the fall of 2009, both of the varieties of coffee grown in India–Arabica and Robusta—suffered heavy losses as a result of unseasonal heavy rains.7 Similarly, in 2010, rainfall occurring after the blossoming stage for Arabica coffee plants delayed the harvest and lowered crop quality.8 The decreased production reported in 2009 and 2010 is part of a long-term trend: from 2002 to 2011, coffee production in India declined by nearly 30 percent.6

Like other food crops, coffee is highly sensitive to rainfall.9 Flower buds require two- to four-month dry periods to form, and the development of leaves and fruit coincides with the beginning of the rainy season.9,10 When rainfall is abundant throughout the year, or when there is no dry period, coffee yields tend to be low.9

A monsoon system brings heavy rains to the country every summer. The average seasonal rainfall is 33.6 inches (853 millimeters), with a historical variation of only 10 percent.11 When rainfall is more than 10 percent above average, widespread floods occur, and when rainfall is more than 10 percent below average, droughts occur.11

Despite the historical regularity of the summer monsoon, the occurrence of extreme rainfall events throughout western India is on the rise.12,13,14 Maximum daily rainfall amounts have been increasing at a rate of 0.3 percent per year—with about half of that amount estimated to be attributable to emissions of heat-trapping gases, primarily from the burning of oil, trees, and gas.14 Extreme rainfall events constitute a growing proportion of the total summer monsoon rainfall,12 and rainfall during the non-monsoon season has been increasing from 1871 until the present.15

Seasonal rainfall totals are strongly correlated with the yield of various crops, but the timing of rainfall within the monsoon season is important as well.11 During drought years, crop production declines, while during years with above average rainfall, production increases.16 During extreme rainfall events, however, crop damage can occur.17,18

Part of a Larger Pattern

Because temperature and rainfall can affect coffee plants directly, by making growing conditions less optimal, and indirectly, by enabling the success of pests such as the coffee berry borer, coffee-growing regions throughout the world are susceptible to climate change. In the coffee-growing Cauca region of Colombia, for example, declines in coffee production have been linked to a combination of rising temperatures and more frequent extreme rainfall events.19 And in Ethiopia, coffee yields dropped by nearly 35 percent from 2002 to 2009, as a result of rising temperatures and widespread infestations of the coffee berry borer beetle, which exploits the warmer conditions.20

What the Future Holds

Because of the continued burning of oil, gas, and trees, temperatures in Karnataka and throughout India are projected to continue to rise during this century.21 A mid-range scenario22 for future emissions of heat-trapping gases projects a warming of about 4.5° F (2.5° C) in Karnataka by 2100.23 Both annual rainfall totals and the number of extreme rainfall events are projected to increase along with climate warming.23

The combination of warming and increases in extreme rainfall events is likely to contribute to a 4–10 percent decrease in overall crop production in South India by the end of the century, even under a low–emissions scenario.16,24 Because of coffee's sensitivity to extremes in both rainfall and temperature, climate change could do great harm to India's coffee industry.

The Coffee Board of India recently introduced a rainfall insurance program to help coffee growers cope with declining yields that result from variability in rainfall. This and other adaptation measures, such as growing the heartier but less desirable Robusta coffee, could help preserve India's coffee industry.8



  1. Photo: Sofi Lundin. Used with permission. All rights reserved.
  2. Discover Geography. 2006. Book 7. Hyderabad, India: Orient Longman Private Limited. Online at: =en#v=onepage&q&f=false
  3. International Coffee Organization. No date. Total production of exporting countries: Crop years commencing 2005–2010. Online at
  4. Coffee Board of India. 2011. Coffee data 2011. Online at
  5. Anupindi, R., and S. Sivakumar. Supply chain reengineering in agri-business: A case study of ITC's e-Choupal. 2007. In: Building supply chain excellence in emerging economies, edited by H.L. Lee and C-Y. Lee. Springer Science + Business Media. Online at
  6. U.S. Department of Agriculture, Foreign Agriculture Service. 2011.
  7. Balaji, F. 2010. Decline in Indian coffee productivity levels alarming: Upasi. Headlines India, September 14. Online at
  8. U.S. Department of Agriculture. 2011. India coffee annual. GAIN report no. IN1147. Washington, DC.
  9. DaMatta, F.M., and J.D. Cochico Ramalho. 2006. Impacts of drought and temperature stress on coffee physiology and production: a review. Brazilian Journal of Plant Physiology 18(1):55–81.
  10. Lin, B.B., I. Perfecto, and J. Vandermeer. 2008. Synergies between agricultural intensification and climate change could create surprising vulnerabilities for crops. BioScience 58(9):847–854.
  11. Challinor, A.J., J.M. Slingo, T.R. Wheeler, P.Q. Craufurd, and D.I.F. Grimes. 2003. Toward a combined seasonal weather and crop productivity forecasting system: Determination of the working spatial scale. Journal of Applied Meteorology 42:175–192.
  12. Goswami, B.N., V. Venugopal, D. Sengupta, M.S. Madhusoodanan, and P.X. Xavier. 2006. Increasing trend of extreme rain events over India in a warming environment. Science 314:1442–1445.
  13. Guhathakurta, P., P. Menon, A.B. Mazumdar, and O.P. Sreejith. 2010. Changes in extreme rainfall events and flood risk in India during the last century. Research report no. 3/2010. Pune, India: National Climate Center, India Meteorological Department. Online at 2520REPORT%252014.pdf+india+extreme+rainfall&hl=en&gl=us&pid=bl&srcid=ADGEESgo6- ngJVajeNKsJprsw4l2DlJGtTU8atiBF7dmlFLL5caP5LPBLY3S mjWoM45IrnXxFxNRLyXNTz_IRyAf_z-kW9AOAmZWpac-xBoo_5uaTY-jPXqImMJdYZ74w3jh4N263RT0&sig=AHIEtbR_xKS5LdPXwboU mJCpZShbXv5Q_w.
  14. Min, S-K., X. Zhang, F.W. Zwiers, and G.C. Hegerl. 2011. Human contribution to more-intense precipitation extremes. Nature 470:378-381.
  15. Krishnakumar, K.N., G.S.L.H.V. Prasada Rao, and C.S. Gopakumar. 2009. Rainfall trends in twentieth century over Kerala, India. Atmospheric Environment 43:1940–1944.
  16. Lal, M. 2011. Implications of climate change in sustained agricultural productivity in South Asia. Regional Environmental Change 11(Suppl.1):S79–S94.
  17. De, U.S., R.K. Dube, and G.S. Prakasa Rao. 2005. Extreme weather events over India in the last 100 years. Journal of the Indian Geophysical Union 9(3):173–187.
  18. Revadekar, J.V., and B. Preethi. 2010. Statistical analysis of the relationship between summer monsoon precipitation extremes and foodgrain yield over India. International Journal of Climatology. doi:10.1002/joc.228.
  19. Rosenthal, E. 2011. Heat damages Colombia coffee, raising prices. New York Times, March 9. Online at
  20. Food and Agriculture Organization of the United Nations. FAOSTAT data for 1993–2009. Rome, Italy. Online at
  21. Christensen, J.H., B. Hewitson, A. Busuioc, A. Chen, X. Gao, I. Held, R. Jones, R.K. Kolli, W.–T. Kwon, R. Laprise, V. Magaña Rueda, L. Mearns, C.G. Menéndez, J. Räisänen, A. Rinke, A. Sarr and P. Whetton. 2007. Regional climate projections. In: Climate change 2007: The physical science basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, edited by S. Solomon, D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor, and H.L. Miller. Cambridge, UK, and New York, NY, USA: Cambridge University Press.
  22. The scenario referred to here is the middle-emissions pathway known as A1B from the Intergovernmental Panel on Climate Change.
  23. Rupa Kumar, K., A.K. Sahai, K. Krishna Kumar, S.K. Patwardhan, P.K. Mishra, J.V. Revadekar, K. Kamala, and G.B. Pant. 2006. High-resolution climate change scenarios for India for the 21st century. Current Science 90(3):334–345.
  24. The scenario referred to here is the low emissions pathway known as B1 from the Intergovernmental Panel on Climate Change.
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