Climate change made S Asia heatwave 30 times more likely

PARIS: The punishing heatwave that scorched India and Pakistan in March and April was made 30 times more likely by climate change, experts in quantifying the impact of global warming on extreme weather events said in a rapid-response report on Monday.

Before the onset of human-caused climate change, the chances of such an event occurring would have been roughly once every 3,000 years, senior author Friederike Otto, a scientist at Imperial College London’s Grantham Institute, told AFP.

Global warming to date of 1.2 degrees Celsius has shortened the so-called return period for extreme heat of similar duration and intensity in South Asia to once-a-century, she and colleagues in the World Weather Attribution (WWA) consortium found. But as the planet continues to heat up, the interval between such killer heatwaves will shrink even further.

If Earth’s average surface temperature rises another four-fifths of a degree to 2C above preindustrial levels, "a heatwave like this one would be expected as often as once every five years", they concluded.

A 2C world is an unsettlingly plausible scenario: current national commitments to curb carbon pollution under the Paris Agreement would see global warming of 2.8C. "Whether today’s most impactful heatwaves could have occurred in a pre-industrial climate is fast becoming an obsolete question," said Otto.

"The next frontier for attribution science is to inform adaptation decision-making in the face of unprecedented future heat," she said by email. "This means the most important aspect of our study is what it says about a 2C world." The March-April period was the hottest on record for that time of year in Pakistan and India. It will be months before the full toll of lives lost and economic damage can be calculated, including hospitalisations, lost wages, missed school days, and diminished working hours.