Northern and western India will face maximum increase in temperature by end of the century while southern India will face maximum increase in tropical nights (when number of 24 hour temperature is more than 20 degrees), the fifth assessment report of the Intergovernmental Panel on Climate Change has said.
The findings are part of the IPCC’s Working Group-I report presenting detailed climate change scenarios for different regions across the globe including South Asia. There is a mid-term (2045-2065) projection and long term (2081-2100) with specific projections for India.
In mid-term, the report projects increase of 2-3°C with warmest temperature focused in the northern part of India and Pakistan. Long term projection is for temperature increase of 3-5°C.
“The warmest daily maximum temperature is projected to increase 4-5°C, with highest temperatures in northern India and Pakistan,” the report says.
The number of tropical nights (that is the number of 24-hour days above 20°C) is projected to increase from between 0 and 80 days, with most concentrated in the southern portion of the India.
The good news from the report coming after six years is that overall rainfall will increase in the Indian sub-continent. In mid-term the IPCC projects an increase of 10% to 20% in precipitation during winter months and 20% increase during September-November period.
In long term, the IPCC says the rainfall will increase by 10% in December to February period and upto 50% during September and November period, meaning the humid days will increase in India.
“Most of this precipitation is projected to occur in the western portion of the region,” the report says
Higher rainfall will not mean more rainy days. It would amount to higher incidence of extreme rainfall events like what happened in June in Uttarakhand this June. With loss of green cover, the annual runoff will be more than 40% of the total rainfall.
Another paradox emerging from the report is that despite more rainfall there would be more water stress areas in the region, especially north and central India.
The report also says that agriculture production would fall by about 9 to 25% in South Asia.
With increase in temperature by around 4%, the report said, the monsoon rainfall --- key to drive India’s food security --- will not be uniform and would witness 10% increase in inter-annual and intra-seasonal variability.
Unlike the past IPCC reports, the working group this time has not predicted any deadline for melting of Himalayan glaciers. The 2007 IPCC report had said that Himalayan glaciers would melt by 2035, for which the panel had apologized.
This time, the report says that melting of Himalayan glaciers would impact 1.2 billion people in the region including China.