Irrigation potential is likely to decrease in the near future, particularly in the Indo-Gangetic plains with the fast melting of Himalayan glaciers. Besides, there would be competition for water use by other sectors.
The estimated loss in wheat production can, however, be minimised to one to two million tonne, if farmers go for early planting of wheat to escape the possible abnormal rise in temperature at the ripening stage.
Losses for wheat and other winter crops would be greater than summer crops.
According to IARI estimate the current average wheat yield is 2.8 tonne per hectare and to meet the demand by 2020, the average wheat yield needs to be raised to 3.9 tonne per hectare. However, there is a hope for increasing the yield of wheat as its biological potential yield is around 8 tonne per hectare and biophysical potential yield is 5 tonne per hectare.
One beneficial impact of warming would be the reduced frequency of damage to crops on account of frost, particularly in northwestern India.
One study done by IARI found that pathogens and insect population strongly dependant upon temperature and humidity. Increase in temperature and humidity would change their population dynamics, resulting in crop production loss.
According to IARI, global warming in short-term is likely to favour agricultural production in temperate regions, particularly Europe and North America and negatively impact crop production in South Asia, Africa and Latin America and thus have consequences on international food prices and trade.
Small changes in temperature and rainfall would have significant impact on quality of fruits, vegetables, tea, coffee, spices, aromatic and medicinal plants. Rise in temperature has already impacted the yield and quality of apples in Himachal Pradesh. India's premium rice Basmati would become vulnerable to temperature rise and coral reefs in the Indian seas would decrease.
The warming effect is likely to increase water, shelter and energy requirement for livestock for meeting the projected milk demand. Heat stress on dairy animals would adversely affect their productive and reproductive performances.
The rise in sea and river water temperatures are likely to affect fish breeding, migration and harvests. Coral reefs in the Indian seas are predicted to decline from the year 2030. Only benefit for the fishery sector would be the availability of new flooded areas.
According to PK Aggarwal one of the IARI noted the contribution of agriculture to greenhouse gas emissions, particularly of methane from paddy fields, enteric fermentation in ruminant animals and nitrous oxide due to application of chemical fertilisers. The gross emissions from Indian agriculture are likely to increase significantly in the future, if attempts are made to boost food production by excessive use of chemical fertilisers.