Climate change made record-breaking deadly heatwaves in Bangladesh, India, Laos and Thailand last month at least 30 times more likely, according to a study published Wednesday.

Parts of India saw temperatures above 44 degrees Celsius (111 Fahrenheit) in mid-April, with at least 11 deaths near Mumbai attributed to heat stroke on a single day. In Bangladesh, Dhaka suffered its hottest day in almost 60 years.

The city of Tak in Thailand saw its highest-ever temperature of 45.4 Celsius, while Sainyabuli province in Laos hit 42.9 Celsius, an all-time national temperature record, the study by the World Weather Attribution group said.

Two deaths were reported in Thailand, but the real toll was likely higher as the extreme heat caused widespread hospitalisations, with the poor and vulnerable the worst affected.

The new study by international climate scientists looked at the average maximum temperature and the maximum heat index, which includes humidity.

"In both regions, the researchers found that climate change made the humid heatwave at least 30 times more likely, with temperatures at least 2 degrees Celsius hotter than they would have been without climate change," WWA said in a statement.

"Until overall greenhouse gas emissions are halted, global temperatures will continue to increase and events like this will become more frequent and severe," it added.

The analysis also found that such events in India and Bangladesh, previously once-a-century, can now be expected around once every five years because of human-caused climate change.

For Laos and Thailand, if global temperatures rise by two degrees Celsius — as will happen within around 30 years if emissions are not cut rapidly — such extreme events could happen every 20 years, compared to every two centuries now, the study said.

"We see again and again that climate change dramatically increases the frequency and intensity of heatwaves, one of the deadliest weather events there are," said Friederike Otto of the Grantham Institute for Climate Change and the Environment, who was involved in the study.

"Still, heat action plans are only being introduced very slowly across the globe. They need to be an absolute priority adaptation action everywhere, but in particular in places where high humidity enhances the impacts of heatwaves," she added.

Scientists were previously reluctant to directly link a particular event to climate change, but in recent years a new field of "attribution science", like that done by the WWA, has emerged.

Some weather events have a more complicated relationship to global warming than others, with the relationship to heatwaves and increased rainfall relatively easy to study.

Other phenomena such as droughts, snowstorms, tropical storms and wildfires are more complicated however, according to the WWA.

Next five years set to be hottest period ever: UN
Geneva (AFP) May 17, 2023 –

It is near-certain that 2023-2027 will be the warmest five-year period ever recorded, the United Nations warned Wednesday as greenhouse gases and El Nino combine to send temperatures soaring.

There is a two-thirds chance that at least one of the next five years will see global temperatures exceed the more ambitious target set out in the Paris accords on limiting climate change, the UN's World Meteorological Organization (WMO) said.

The hottest eight years ever recorded were all between 2015 and 2022, with 2016 the warmest — but temperatures are forecast to increase further as climate change accelerates.

"There is a 98-percent likelihood that at least one of the next five years, and the five-year period as a whole, will be the warmest on record," the WMO said.

The 2015 Paris Agreement saw countries agree to cap global warming at "well below" two degrees Celsius above average levels measured between 1850 and 1900 — and 1.5C if possible.

The global mean temperature in 2022 was 1.15C above the 1850-1900 average.

The WMO said there was a 66 percent chance that annual global surface temperatures will exceed 1.5C above pre-industrial levels for at least one of the years 2023-2027, with a range of 1.1C to 1.8C forecasted for each of those five years.

– 'Uncharted territory' –

"WMO is sounding the alarm that we will breach the 1.5C level on a temporary basis with increasing frequency", said the agency's chief Petteri Taalas.

"A warming El Nino is expected to develop in the coming months and this will combine with human-induced climate change to push global temperatures into uncharted territory.

"This will have far-reaching repercussions for health, food security, water management and the environment. We need to be prepared."

El Nino is the large-scale warming of surface temperatures in the central and eastern equatorial Pacific Ocean. The weather phenomenon normally occurs every two to seven years.

Typically, El Nino increases global temperatures in the year after it develops — which in this cycle would be 2024.

Wednesday's predictions show "we haven't been able to limit the warming so far and we are still moving in the wrong direction", Taalas told a press conference.

He said it could take until the 2060s to phase out the negative trend and stop things getting worse.

Heat gets trapped in the atmosphere by so-called greenhouse gases, which are at a record high.

The major greenhouses gases are carbon dioxide, plus methane and nitrous oxide.

"The return to normal level might take even thousands of years because we already have such a high concentration of carbon dioxide, and we have lost the melting of glaciers and sea level game," said Taalas.

"There's no return to the climate which persisted during the last century. That's a fact."

– 'Nobody untouched' by changes –

Mean global land and sea near-surface temperatures have increased since the 1960s.

The chances of temperatures temporarily exceeding 1.5C above the 1850-1990 average have risen steadily since 2015, a year in which they were considered close to zero.

"It will be sad the day we pass 1.5 degrees but it's not a reason to give up," said Leon Hermanson of Britain's Met Office national weather service, the WMO's lead centre on yearly to 10-yearly climate predictions.

"We need to emit as few as possible of the greenhouse gases and any emissions that we manage to cut will reduce the warming and this will reduce the big extreme impacts.

"Nobody is going to be untouched by these changes and it's leading already to floods across the world, droughts and big movements of people."

Taalas added that while predictions for climate averages are fairly strong, climate extremes predictions are "still a bit unknown, and the biggest impacts of climate change are felt through these extremes".