Kochi: Many parts of Asia including India witnessed record-breaking temperatures and heatwaves in April this year. Now, a preliminary study released on May 15 shows that climate change made these heat waves more frequent, and more extreme.
As per the ‘rapid study’ by scientists associated with World Weather Attribution (WWA), a collective that studies the impact of climate change on extreme weather events worldwide, the heatwaves that swept across Asia were made more likely by climate change. Climate change also made the likelihood of such a heatwave occurring across south Asia – including India – 45 times more likely and 0.85 degrees Celsius hotter than it would otherwise be, their report found.
Mercury rising across Asia
Summer temperatures have been breaking records across the world. This April was the 11th consecutive month being the warmest for the respective month of the year, as per Europe’s Copernicus Climate Change Service press release on May 7.
In India too, it has been no different: March-April 2022 was one of the hottest months in more than a century in parts of India. The heat waves that parts of northern and northwestern India witnessed in April 2023 claimed several lives, apart from affecting crops, livestock and livelihoods. Looking at temperature data, scientists associated with WWA found that climate change — caused by human activity such as the burning of fossil fuels that release greenhouse gases into the atmosphere — made the 2023 heat waves around 30 times more likely in India and Bangladesh.
On April 1 this year, the India Meteorological Department (IMD) warned that many parts of India would witness not just a hot but an abnormally hot summer. The IMD had also cautioned that the number of heat wave days that many regions witness would also be higher than usual.
And as the month unfolded, reports came in of heat waves across the country. Many parts of eastern India witnessed the hottest April on record, per reports. Several other countries in Asia – from Lebanon to Vietnam and Cambodia – too witnessed the impacts of heat waves.
Climate change is amping up the heat
Most of Asia experienced temperatures of up to and over 40 degrees Celsius, noted WWA scientist Friederike Otto, Senior Lecturer in Climate Science at the Grantham Institute – Climate and the Environment, Imperial College London, in a virtual press conference on May 14.
Scientists with the WWA analysed three different sets of temperature data for three regions across the continent: three-day averaged daily maximum temperatures in March-April for west Asia (Jordan, Syria, Israel, Palestine and Lebanon), the averaged daily maximum temperatures across 15 days annually in the Philippines, and the average April temperatures over South Asia (India, Bangladesh, Myanmar, Thailand, Lao PDR, Vietnam and Cambodia).
In south Asia, their results show that extreme temperatures are now about 45 times more likely and 0.85 degrees Celsius hotter due to climate change.
“These results align with our previous studies, where we found that climate change made the extreme heat about 30 times more likely and 1 Deg C hotter,” the report read.
The team also found that the heat wave that struck the Philippines would have been nearly impossible if it hadn’t been for climate change. In west Asia, the heat wave made living conditions worse for Palestinians as they struggled in relief camps with Israel continuing to attack civilians; climate change increased the probability of the event by about a factor of 5, the report said.
“From Gaza to Delhi to Manila, people suffered and died when April temperatures soared in Asia,” Otto said in a press release. “Heatwaves have always happened. But the additional heat, driven by emissions from oil, gas and coal, is resulting in death for many people. If humans continue to burn fossil fuels, the climate will continue to warm, and vulnerable people will continue to die.”
Impacts of the El Niño
The team also studied the impacts of the El Niño Southern Oscillation (ENSO), a complex climate pattern influenced by fluctuating sea surface temperatures and atmospheric changes in the tropical Pacific Ocean, on the occurrence of the heatwave over south Asia. The ENSO can cause what are called El Niño years (usually characterised by weak monsoons and reduced rainfall in many regions including most of south Asia), neutral conditions and La Niña years (which are often cooler and wetter).
Though the past year has been an El Niño year, which means that temperatures can be higher and rains lesser, the impacts of climate change far overshadowed those that would be seen in a normal El Niño year.
The El Niño year made a difference for it did contribute to the heat waves, said Mariam Zachariah, researcher at Grantham Institute – Climate Change and the Environment, Imperial College London, who is also among the team of researchers associated with the WWA that conducted the rapid study. “The ENSO did make a difference but not as much as climate change did,” Zachariah said in the online press conference on May 14.
While results of the study are not peer-reviewed yet, all such studies by the WWA are later peer-reviewed and there have not been any changes in the numbers, said Otto during the virtual press conference.
“All heat waves occurring today are made more hot, more frequent and intense due to climate change,” Otto said. “So it is right to say that there is a climate change component in a heatwave if it occurs today.”
While some countries – such as India – have heat action plans in place, there’s more than needs to be done, per the report. Different sections of people are more vulnerable to the impacts of heat waves, and heat plans need to cover all vulnerable sections, with plans comprising “mandatory regulations such as workplace interventions for all workers to address heat stress, such as scheduled rest breaks, fixed work hours, and rest-shade-rehydrate programs”, the report noted. These regulations are not yet part of worker protection guidelines in the affected regions, it said.
But…it’s not over yet
India’s tryst with heat waves this year, however, isn’t over yet, even as its elections still continue.
While the IMD has predicted that the much-awaited south west monsoon is very likely to advance into the South Andaman Sea, and some parts of southeast Bay of Bengal and Nicobar Islands by around May 19, heat waves are predicted across some parts of the country.
As per a press release by the India Meteorological Department on May 14, northwestern India will witness a fresh heatwave from May 16 onward.
Severe heat wave conditions are “very likely” in parts of West Rajasthan on May 17 and 18, as well as in isolated pockets of Punjab and south Haryana on May 18, the release said. Heat wave conditions are likely to occur in some parts of the Konkan coast on May 14 and 15, and over West Rajasthan from May 15-18. Uttar Pradesh, Punjab, southern Haryana and Bihar will also likely witness a heat wave from May 16-18, as will northern Madhya Pradesh and eastern Rajasthan in the two days to follow.
The Konkan coast meanwhile is also likely to witness hot and humid weather, according to the IMD release.
