Agriculture
        
Agricultural productivity can be affected in two ways: one, directly, due to changes in temperature, precipitation or CO₂ levels and two, indirectly, through changes in soil, distribution and frequency of infestation by pests, insects, diseases or weeds.

Sixty five per cent of Indian agriculture is heavily dependent on natural factors such as rainfall. It is also restricted by a lack of complementary inputs and institutional support systems. In tropical Asia, although wheat crops are likely to be sensitive to an increase in maximum temperature, rice crops would be vulnerable to an increase in minimum temperature. The adverse impacts of likely water shortage on wheat productivity in India could be minimized to a certain extent under elevated CO₂ levels; these impacts, however, would be largely maintained for rice crops, resulting in a net decline in rice yields. Acute water shortage conditions combined with thermal stress could adversely affect wheat and, more severely, rice productivity in India even under the positive effects of elevated CO₂ in the future.

Sinha S K and Swaminathan M S (1991) estimate that a 2°C increase in mean air temperature could decrease rice yield by about 0.75 ton/hectare in the high yield areas and by about 0.06 ton/hectare in the low yield coastal regions. Further, a 0.5°C increase in winter temperature would reduce wheat crop duration by seven days and reduce yield by 0.45 ton/hectare. An increase in winter temperature of 0.5 °C would thereby translate into a 10% reduction in wheat production in the high yield states of Punjab, Haryana and Uttar Pradesh. Rao D G and Sinha S K (1994) in their crop-simulation study estimate that under a 2 × carbon dioxide climate change scenario, the wheat yields could decrease by 28%-68% without considering the carbon dioxide fertilization effects.

Disclaimer The outcome of these studies reflects the author's viewpoint and not that of the Government of India.

The loss in farm-level net revenue will range between 9 and 25% for a temperature rise of 2-3.5°C (Kumar K and Parikh J 1998). A rise in mean temperature of 2°C and a 7% increase in mean precipitation will reduce net revenues by 12.3% for the country as a whole. Agriculture in the coastal regions of Gujarat, Maharashtra and Karnataka is likely to be affected negatively. Small losses are also indicated for the major foodgrain-producing regions of Punjab, Haryana, and western Uttar Pradesh (Sanghi A, Mendelsohn R and Dinar A 1998).

Disclaimer The outcome of these studies reflects the author's viewpoint and not that of the Government of India.

    
References

Kumar K and Parikh J. 1998
Climate change impacts on Indian agriculture: the Ricardian approach
In Measuring the Impact of Climate Change on Indian Agriculture, edited by A Dinar, R Mendelsohn, Everson, J Parika, A Sanghi, K Kumar, J Mckinsey and S Lonergan.
Washington, DC: The World Bank [World Bank Technical Paper No 402]

Rao D G and Sinha S K. 1994
Impact of climate change on simulated wheat production in India
In Implications of Climate Change for International Agriculture: Crop Modeling Study, edited by C Rosenzweig and A Iglesias.
Washington, DC: United States Environment Protection Agency

Sanghi A, Mendelsohn R and Dinar A. 1998
The climate sensitivity of Indian agriculture
In Measuring the Impact of Climate Change on Indian Agriculture, edited by A Dinar, R Mendelsohn, Everson, J Parika, A Sanghi, K Kumar, J Mckinsey and S Lonergan.
Washington, DC: The World Bank [World Bank Technical Paper No 402]

Sinha S K and Swaminathan M S. 1991
Deforestation, climate change and sustainable nutrition security: a case study of India
Climatic Change 19: 201-209

Overview Forests Coastal areas

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