Over the next three decades, Karnataka is projected to experience warmer weather and an increase in heavy rainfall events. The State is prone to loss and damage by droughts, floods due to extreme rainfall, landslips, hailstones, and forest fires. These are some of the findings of a study by the Center for Study of Science, Technology and Policy (CSTEP) which projected changes in climate patterns from 2021–2050 when compared with the 30-year period from 1991–2019 in Andhra Pradesh, Telangana, Kerala, Karnataka, and Tamil Nadu.
“Consecutive droughts impact 54% of the geographical area (18 of the 30 districts). Below normal rainfall or dry spells for more than three consecutive weeks are the main factors that cause droughts in the State. Poor storage facilities in minor irrigation tanks and depleting groundwater resources exacerbate the problem. According to the Vulnerability Atlas of India (2019), about 15% of the total geographical area is under moderate earthquake damage risk zone, 10 districts are prone to flooding, and hilly areas of four districts are prone to landslips due to heavy rainfall events,” the study said.
Increase in temperature
Indu K. Murthy, sector head for Climate, Environment and Sustainability at CSTEP, told The Hindu that in the last three decades (1991–2019), there has been an increase in the summer maximum temperature by 0.18° Celsius to 0.61° Celsius and the winter minimum temperature by 0.3° Celsius to 0.65° Celsius in different districts of Karnataka. The rainfall shows an increasing trend during this period in all the districts, with up to 15% to 25% increase in the Western Ghats districts, but has been highly variable.
“Climate change projections using an ensemble of models for the next 30 years (2021–2050) under moderate emissions and high emissions scenarios indicate a much warmer and wetter future for Karnataka. An increase in summer maximum temperature by 0.5° Celsius to 1.5° Celsius with a majority of the districts projected to warm by 1° Celsius to 1.5° Celsius, particularly under the high emissions scenario. This includes the already warm districts of North Karnataka. Winter minimum temperature is also projected to increase, particularly higher in the northern districts of Karnataka, by up to 2° Celsius,” she explained.
She added that the number of rainy days (more than 2.5 mm/day) are projected to increase in all the districts of Karnataka. “Under the high emissions scenario, up to 26% increase in rainfall during the kharif season is projected in Kolar district, and during the rabi season the increase is up to 34% in Bidar district. Rainfall variability during the kharif season is projected to increase in a majority of the districts by up to 14%, and this includes many of the low rainfall northern districts of Karnataka. However, rainfall variability during the rabi season is projected to decline in all the districts of Karnataka,” Dr. Murthy said.
Heavy rainfall events
Heavy rainfall events are projected to increase in all the districts of Karnataka. The increase is notable in the districts of Kodagu, Udupi, and Uttara Kannada. Even in some of the North Karnataka districts of Yadgir, Bidar, and Koppal, and in Kolar, more than five additional days of heavy rainfall are projected every year in the next 30 years, she added.