World on fire: How climate crisis is making heatwaves more intense

2023 was officially announced as the hottest year on record. But 2024 could very well throw up a new record.

From Thailand and Bangladesh to India, Nigeria, Mexico, and beyond, many countries are experiencing blazing heatwaves and unprecedented droughts as the mercury levels breach scorching marks.

A growing climate crisis, experts say, is exacerbating extreme weather events, resulting in soaring temperatures, more frequent droughts, and fiercer heatwaves.

And it is only going to get worse.

In India, a severe heatwave tearing through several parts of the country has killed hundreds of people due to heatstrokes. Bats are dropping dead, monkeys suffering heatstrokes and tigers venturing into human habitats in search of water.

In Bihar and Uttar Pradesh, two northern Indian states, as well as northeastern Odisha, government officials reported the death of at least 33 people, including election staff, due to heat-related problems last week.

"Heatwaves are a silent killer," says Aditi Mukherji, climate change adaptation and mitigation impact action platform director at CGIAR, the world's largest global agricultural innovation network and research partnership.

"High heat coupled with high humidity (that is, high wet bulb temperature) is lethal to humans as we are not physiologically equipped to work under such high heat and humidity," Mukherji tells TRT World.

"The number of heat-related deaths in India during the recent heatwaves should ring alarm bells," adds Mukherji, who co-wrote the Intergovernmental Panel on Climate Change (IPCC)'s latest synthesis report published in March 2023.

Experts cite the wet bulb temperature to explain the dangerous effects of intense heat on the human body.

Elevated wet bulb temperatures can be dangerous because the human body, which typically maintains an internal temperature of around 37 degree Celsius, releases heat through sweating, making it more difficult to dissipate excess warmth when both humidity and air temperature are high.

In extremely humid conditions, sweat can evaporate very slowly or not at all, leading not only to discomfort but also potentially to health issues.

Those without access to cooling facilities are most susceptible, Mukherji notes, adding that, like all climate impacts, "the most poor and the vulnerable are the most affected."

Record-breaking heat

"Climate and attribution science is clear, heatwaves are happening more frequently and with more extremes due to human-caused climate change," she says, citing IPCC reports and studies that "have clearly attributed heatwaves to the excess carbon dioxide emissions we have put in the atmosphere in the last 150 years."

She adds urban development has been so dependent on burning fossil fuels and decimating forests that it has resulted in climate change in the first place. In areas where trees have been replaced by concrete jungles, the "urban heat island effect" exacerbates heat.

On May 29, the capital city of New Delhi reported its highest temperature on record at 52.9 degrees Celsius, though days later, the government attributed the figure to a faulty weather sensor.

Even without the fault, Delhi and several other parts of India are experiencing temperatures close to 50 degree Celsius this year. According to the Reuters news agency, which cited the Indian Meteorological Department (IMD), the highest temperature previously recorded in New Delhi was 48.4 degrees Celsius in May 1998.

Professor at Monash University's School of Earth, Atmosphere and Environment in Australia, Dietmar Dommenget, tells TRT World the most apparent impact of skyrocketing temperatures affecting countries like India and elsewhere is that humans are getting into conditions that we are not used to, "and so, for every part of the world, we are warming typically over land — as will be in the current few decades — two to three degrees warmer than normal."

"When you start getting into 50 degrees — even for a country like India that is used to hot temperatures, 50 degrees is really dangerous, and it gets to a level where it becomes a problem for society," says Dommenget, who is also an editor at the Journal of Climate, a peer-reviewed scientific journal published semi-monthly by the American Meteorological Society.

According to the latest IPCC report, which CGIAR's Mukherji contributed to, there has been some progress in terms of more investments in renewables.

The very high-end temperature increases of 3.5 to four degrees by the end of this century were taken off the table due to current climate pledges, Mukherji says, "yet we are still on a track to a 2.7 to 3.1-degree world by 2100 — which is far too hot."

"The impacts at 1.2 degree world are already quite severe particularly for tropics like India and Southeast Asia," she explains. "Hence, while climate action is happening, it is not happening at the pace and quantum fast enough for what is needed to limit ourselves to a 1.5 to 2 degree world by end of the century."

Lack of water

In Mexico, where people in parts of the country like Mexico City are experiencing drought and water shortages, record-breaking temperatures persisting for over a month have devastated human life and the environment.

The scorching heat engulfing much of the country has already claimed the lives of dozens of people, and howler monkeys have even reportedly been falling dead from trees because of how hot it is.

According to the National Meteorological Service, the "highest temperature since records have been kept" hit 34.7 degree Celsius in late May at the Tacubaya observatory.

Mexico City depends on the Cutzamala system, a collection of three reservoirs that supplies a significant portion of its water. However, due to the drought, the system is currently functioning at a historically low capacity of about 28 percent.

While playing a significant role, the effects of the climate crisis are not solely responsible for what's happening in Mexico, says National Autonomous University of Mexico (UNAM) climate scientist and researcher Ruth Cerezo-Mota.

It's true that several regions of the world are experiencing more frequent and more intense extreme weather events, and that, she adds, with each degree of increase in the temperature, those events are more likely to occur. However, other elements play into Mexico City's crisis as well.

"There is a severe scarcity of water," Cerezo-Mota tells TRT World. "How did it get that bad? Short answer: A long history of very poor administration, congestion, and planning. The city is one of the most populated in the world, and it has grown without proper planning."

She adds that inefficient water management and infrastructure also pose a challenge through old pipes that spill and waste water. According to SACMEX, Mexico's federal district water operator, close to 40 percent of water is lost as a result of leaky pipes during transit.

Experts estimate that the 22 million-strong metropolitan area could run out of water by June 26, also known as Day Zero, unless it rains, a factor exacerbated by climate impacts.

"The rainy season (and hurricane seasons in both the Pacific and Atlantic) are about to start... the only problem with that is that if what we get are extreme events of rainfall, the soil and ground will get saturated really fast, and instead of infiltrating, there will be flooding," Cerezo-Mota explains.

"So, hopefully, we have a normal rainy season with enough water to replenish the water basins," she adds.

Water shortages in Mexico City have traditionally impacted less affluent communities. However, wealthier areas are now also experiencing shortages as a result of high temperatures, reduced rainfall, and inadequate infrastructure, leading to a widespread crisis across the city.

"We need a real program that includes the preservation of natural reserves, reforestation (with native plants), and infrastructure to capture the rain."

Interconnected climate

The climate system is fairly connected, associate professor Dommenget says. "Things that happen in one region are usually connected to other regions due to connecting oceans and atmospheres.

"This is why we see a global impact of the warming currently, and last year, we had very unusually warm oceans, especially in the Atlantic and also in the Indian Ocean," he explains, adding that climate change will not impact everybody equally.

It doesn't help that our climate is fairly chaotic, Dommenget says, where regions with more dramatic changes in heatwaves, rainfall patterns, and other extreme weather events can be more affected. Coastal areas that are fairly flat and exposed to strong rainfall events or tropical cyclones, for example, are relatively in danger of future climate change, he adds.

"Regions like Bangladesh can be very strongly affected by these extreme events, and, also, regions like in the south of the United States where New Orleans is an exposed location, climate change can have really serious problems for these regions.

"These effects can be, in some regions, very dramatic, but in other regions, you might not see anything."

It may sound like a broken record at this point, but at the end of the day, what is clear, according to all three experts, is that more action is needed to mitigate the effects of the climate crisis.

"One of the problems in climate change is we've been talking about this for decades, and we have been warning the society for decades, but we are not responding enough," Dommenget says.

As he puts it, "It is like you are driving a car. You know that you have to step on the brakes because there's something in front of you that you have to immediately react to —you are braking, but you are not braking enough."