A recent analysis of the last 58 years’ (1960 to 2017) weather data of Karnataka has indicated a considerable shift in rainfall pattern in the State, which has a bearing on agriculture and water security.
It calls for changes in the present cropping pattern and agro plans in the light of the observed shift in rainfall and temperature variation that can lead to frequent recurrence of extreme weather conditions.
The study titled ‘Climate Change Scenario in Karnataka: A Detailed Parametric Assessment’ was conducted by Karnataka State Natural Disaster Monitoring Centre (KSNDMC) and its findings have long-term implications for both food and water security.
The core team which conducted the study was led by G.S. Srinivasa Reddy, former Director, KSNDMC, and the scientists involved in the project analysed the variations in the amount of rainfall, rainy days, frequency of rainfall events, dry spells, fluctuations in temperature, number of years when the rainfall was below normal etc.
Dr. Reddy told The Hindu that the study shows a reduction in the amount of annual rainfall in Kodagu, Kalaburagi, Yadgir, Dakshina Kannada and Uttara Kannada, while there is an increase in rainfall over Shivamogga and Hassan districts. “There is also a shift in the rainfall pattern in July and the quantum of rainfall is increasingly getting concentrated for a few days in August, which leads to floods as being observed since the last three years,” Dr. Reddy added.
He pointed out that the cumulative water storage in the four dams in the Cauvery basin in the State in the last week of July this year was nearly 40 tmcft against the gross capacity of nearly 115 tmcft. But the scenario changed due to heavy rains concentrated for a few days in the first two weeks of August, and the reservoirs are now full to the brim.
He said most of the State’s agricultural and water resource management plans are drawn based on the data that was available before 1960. “Climate change has led to significant variation in the weather at the local levels and this should be factored in while conceiving crop pattern and water resource management,” Dr. Reddy added.
The cropping pattern based on the pre-1960 rainfall data should be changed in the light of shift in rainfall pattern during the last 60 years, according to Dr. Reddy.
The study showed that Kodagu and Dakshina Kannada and other catchment areas display a net reduction in the rains and Mr. Reddy pointed out that this has implications for water security of the State. He said even a 1% rainfall deficiency amounts to a decline of 30 mm to 40 mm of annual rains.
Also, the State as a whole experiences a higher pre-monsoon rain, northeast monsoon and annual rainfall whereas southwest monsoon rainfall shows a decreasing trend as per the KSNDMC study. The rainfall shows a decreasing trend in majority of the taluks of the State in June and July and increasing rainfall is observed in August, especially in south-interior and north-interior Karnataka.