The destructive heatwave that gripped Pakistan and India over the last two months is unprecedented but worse, perhaps far worse is on the horizon as climate change continues apace, top climate scientists told AFP. Even without additional global warming South Asia is, statistically speaking, ripe for a “big one” in the same way that California is said to be overdue for a major earthquake, according to research published this week. Extreme heat across much of India and neighbouring Pakistan in March and April exposed more than a billion people to scorching temperatures well above 40 Celsius (104 Fahrenheit). The hottest part of the year is yet to come. “This heatwave is likely to kill thousands,” tweeted Robert Rohde, lead scientist at Berkeley Earth, a climate science research non-profit. The number of excess deaths, especially among the elderly poor, will only become apparent in hindsight. Heatwave mortality in India has increased by more than 60 percent since 1980, according to the country’s Ministry of Earth Sciences. But “cascading impacts” on agricultural output, water, energy supplies, and other sectors are already apparent, World Meteorological Organization chief Petteri Taalas said this week. Air quality has deteriorated, and large swathes of land are at risk of extreme fire danger. Power blackouts last week as electricity demand hit record levels served as a warning of what might happen if temperatures were to climb even higher. For climate scientists, none of this came as a surprise. “What I find unexpected is most people being shocked, given how long we have been warned about such disasters coming,” Camilo Mora, a professor at the University of Hawaii, told AFP. “This region of the world, and most other tropical areas, are among the most vulnerable to heatwaves.” What a new normal may reflect is when Mora in a landmark 2017 study calculated that almost half the world’s population will be exposed to “deadly heat” 20 days or more each year by 2100, even if global warming is limited to less than two degrees Celsius. the fundamental objective of the Paris Agreement. To what extent is climate change to blame that Scorched Earth temperatures are now dropping in India and Pakistan? Scientists at Imperial College London’s Grantham Institute, led by Friederike Otto, a pioneer in the field of attribution science, are crunching the numbers. “We are still working out how much more likely and intense this particular heatwave has become,” he told AFP. “But there is no question that climate change is a huge game changer when it comes to extreme heat,” she added. . “What we see right now is going to be normal, if not great, in a 2C to 3C world.” The Earth’s surface, on average, is 1.1°C above pre-industrial levels. National carbon reduction pledges under the Paris Agreement, if fulfilled, would still cause the world to warm 2.8 degrees. In India and Pakistan, “more intense heat waves of longer duration and more frequent are projected,” the Intergovernmental Panel on Climate Change (IPCC) said in a recent landmark report. “Before human activities increased global temperatures, we would have seen heat hit India once every 50 years,” said Marian Zachariah, a researcher at Imperial College London. “But now we can expect such high temperatures once every four years.” Continued global warming, in other words, guarantees greater extremes of heat in the coming decades. But things can get worse even sooner, according to a new study in Science Advances. A team led by Vikki Thompson of the University of Bristol ranked the world’s most severe heat waves since 1960. Their benchmark, however, wasn’t maximum temperatures, but how hot it got compared to what would be expected. for the region. Surprisingly, South Asia was nowhere near the top of the list. “When defined in terms of deviation from the local norm, heatwaves in India and Pakistan to date have not been that extreme,” Thompson explained in a comment. By that measure, the worst scorcher on record in the past six decades was in Southeast Asia in 1998. “An equivalent atypical heatwave in India today would mean temperatures above 50C across large swaths of the country,” Thompson said. “Statistically, an unprecedented heatwave is likely to hit India at some point.” What makes extreme heat deadly is high temperatures combined with humidity, a steam room mix with its own measuring stick: the wet-bulb (WB) temperature. When the body overheats, the heart speeds up and sends blood to the skin where sweat cools it. But above a threshold of heat plus humidity, this natural cooling system shuts down. “Think of it like a sunburn but inside your body,” Mora said. A wet bulb temperature of 35°C WB will kill a healthy young adult within six hours. Last week, the central Indian city of Nagpur briefly registered 32.2 WB. “The increase in heat waves, floods, cyclones, and droughts that we have seen in this region so far responds to just one degree Celsius,” Roxy Mathew Koll, a climatologist at the Indian Institute of Tropical Meteorology, told AFP. “It’s hard for me to even imagine the impacts when the increase in global temperatures doubles.”