Decrease in Global Warming Will Not Reduce South Asian Heat Waves

South Asian residents periodically experience deadly heat waves at the current level of warming. However, a new study has projected that in the future, even with just 2 degrees Celsius of warming, South Asian exposure to heat stress will nearlyincrease three-folds.

Moetasim Ashfaq, co-author, said, "The future looks bad for South Asia, but the worst can be avoided by containing warming to as low as possible. The need for adaptation over South Asia is today, not in the future. It's not a choice anymore."

‘South Asians are especially vulnerable to extreme heat waves because the area already experiences very hot, humid summers.’

According to the Intergovernmental Panel on Climate Change, the earth has warmed by 1 degree Celsius since the start of the Industrial Revolution. It may reach 1.5 degrees Celsius of warming in 2040 if the current trajectory remains, which leaves little time for South Asian countries to adapt.

"Only half a degree increase from today is going to cause a widespread increase in these events," Ashfaq said.

The research team used climate simulations and projections of future population growth to estimate the number of people who will experience dangerous levels of heat stress in South Asia at warming levels of 1.5 and 2 degrees Celsius.

They estimated the wet bulb temperature residents will experience, which is similar to the heat index, as it takes into account humidity as well as temperature. A wet bulb temperature of 32 degrees Celsius (89.6 degrees Fahrenheit) is considered to be the point when labor becomes unsafe, and 35 degrees Celsius (95 degrees Fahrenheit) is the limit to human survivability - when the body can no longer cool itself.

Analysis revealed that at 2 degrees of warming, exposure to unsafe labor temperatures will increase over two times, and exposure to lethal temperatures will be 2.7 times of recent years.

Further, limiting warming to 1.5 degrees Celsius may reduce that impact by half, but extreme temperatures will still be common across South Asia. An increase in heat events that create unsafe labor conditions are likely to occur in regions of West Bengal, Uttar Pradesh, Punjab, Sindh, Karachi, Kolkata, Mumbai, Hyderabad and Peshawar.

South Asians are especially vulnerable to extreme heat waves because the area already experiences very hot, humid summers. Majority of the population lives in densely populated cities without regular access to air conditioning, and about 60% perform agricultural work and can't escape the heat by staying indoors.

Ashfaq said there is an urgent need to radically alter the current trajectory of greenhouse gas emissions.

TV Lakshmi Kumar, an atmospheric scientist, commented, "A policy framework is very much needed to fight against heat stress and heat wave-related problems. India has already committed to reduce emissions to combat climate change issues."



Source: Eurekalert