‘Climate change’ as a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods. The major characteristics of climate change include rise in average global temperature, ice cap melting, changes in precipitation, and increase in ocean temperature leading to sea level rise.
Impact of climate change on rainfall pattern:
- A new study says extreme rainfall events are on the rise in India and attributes the trend to man-made emissions. The trend is likely to become more prominent by mid-century, particularly in southern and central India.
- Rising temperatures will intensify the Earth’s water cycle, increasing evaporation. The rate of evaporation from the ocean is increasing as the world warms., the higher rate of evaporation contributes to more extreme rain and snow events.
- Precipitation over the Krishna basin is likely to increase in the 2020-2050, and rainfall in the districts in the southern part of the basin is likely to increase by as much as 10% in the kharif season.
- Decline in precipitation of up to 20% over the Cauvery basin is projected for the kharif season.
- As a result of depletion of the ozone layer, there will be more heat trapping gases in the atmosphere, which, according to climate models, will shift rainfall/precipitation patterns.
How erratic rainfall patterns affect food security:
(i) Climate change is likely to cause stronger storms and more floods, which can damage crops.
(ii) Droughts caused by climate change could reduce the amount of water available for irrigation.
(iii) The crops that are grown for food need specific conditions to thrive, including the right temperature and enough water. A changing climate could have both positive and negative effects on crops.
For example, the northern parts of the United States have generally cool temperatures, so warmer weather could help certain crops grow.
In southern areas where temperatures are already hot, even more heat could hurt crop growth.
(iv) Higher temperatures and changing rainfall patterns could help some kinds of weeds and pests to spread to new areas.
(v) Other than the effect of high and low rainfall on cropping patterns, it is predicted that phenomena such as coastal flooding will reduce the amount of land available for agriculture.
(vi) El Nino provides another example of how agricultural production patterns and food securities are impacted. In Southern Africa (2016), it severely weakened crop prospects, triggering a 25% cut in wheat production. In India too, following a poor monsoon, the area of wheat crop was cut.
- There seems the need for initiating adaptation and mitigation to avoid the risk and damage due to extreme rain and flooding.
- Agricultural adaptation options can be grouped as technological developments, government programmes, farm production practices and farm financial management.
- Farmers may be able to prepare for climate change by planting crops during different times of the year, or by planting crops that can survive better in hot and dry conditions.