Mohammad Shukkur Ali, a resilient rickshaw puller in his 50s, confronts the unforgiving streets of Dhaka, the capital of Bangladesh, with unwavering dedication. His occupation, already demanding, exacts a substantial physical toll.

This year, however, the relentless heat has added an extra layer of hardship to his daily toil. In April, Dhaka experienced a record-breaking high temperature of 40.6°C (105.8°F).

“I need to work because we are poor,” he said.

Mr. Ali, who shares a rented room with his wife and two children, feels compelled to persevere through these uncomfortable conditions. His daily routine involves eight-hour shifts in Gulshan, an affluent district in Dhaka boasting luxurious apartments, sprawling corporate offices, and several foreign embassies. To even gain access to this area, he must wear a jacket over his shirt, a sort of uniform that exacerbates the sweltering heat.

In addition to the scorching temperatures, fuel shortages resulting from the Ukraine conflict have led to frequent power outages, worsening the situation for millions of people worldwide.

Across the globe, including North America and Europe, numerous regions have endured scorching heatwaves this year. Several cities have reported record-breaking temperatures, prompting scientists to predict that July will likely become the hottest month ever recorded.

In a concerted effort to combat climate change, nations have committed to limiting global warming to no more than 1.5°C above pre-industrial levels—a critical threshold to mitigate the most severe climate change effects by reducing fossil fuel emissions. However, scientists caution that there is a significant likelihood of breaching this limit within the next four years.

Currently, the world is approximately 1.1°C warmer than pre-industrial times, but distressingly, Asia has experienced even more substantial warming this year.

A recent report compiled by nearly two dozen climate scientists revealed that earlier this year, temperatures in many parts of Asia soared by 2°C, a region that is home to over 4.5 billion people. The repercussions of this year’s extreme heatwave have reverberated across the continent.

Between May and August, South Korea recorded at least 23 fatalities resulting from heat-related injuries—more than triple the previous year’s figure. Temperatures in some parts of the country climbed as high as 38°C. During the 25th World Scout Jamboree in Buan, hundreds of participants suffered heat exhaustion, while other regions experienced heavy rainfall and floods.

Japan, in mid-July, issued heatstroke warnings across half of the country after many areas set temperature records. Tokyo, the capital, witnessed an unprecedented high of 38°C (100.4°F)—eight degrees higher than an average Tokyo summer. In just one week of July, over 9,000 people were hospitalized across the country due to heatstroke, according to local media reports.

China endured its highest temperature ever when a dusty town in western Xinjiang province reached a scorching 52°C (125°F) in July. A month earlier, Beijing recorded its hottest June day in over six decades, with temperatures hitting 41.1°C (105.9°F).

In India, a severe heatwave swept through the northern regions in May, with temperatures soaring to a record-breaking 49.2°C (120.5°F) in parts of Delhi, the capital city.

In Southeast Asia, both April and May brought record-high temperatures to several countries, coinciding with the region’s typical hottest months.

Heatwaves represent one of the world’s deadliest natural disasters, sometimes claiming more lives than earthquakes, typhoons, or floods. Additionally, they can melt roads, damage infrastructure, and trigger forest fires. Often considered a “silent disaster,” heatwaves can lead to indirect fatalities by exacerbating pre-existing conditions like diabetes, dehydrating the body, and straining healthcare systems.

Extreme heat also places immense stress on the heart, with a mere half-degree increase in core body temperature elevating the heart rate by ten beats per minute. Heatstroke becomes a serious concern when core body temperature remains above 40°C (104°F) for extended periods, potentially resulting in organ failure, cardiac arrest, and death if untreated.

Heat increases moisture in the air and “the sweat on your skin simply can’t evaporate [and take the heat away] in the humidity,” said Winston Chow, an associate professor of Urban Climate at Singapore Management University. “It becomes dangerous when the body loses the natural ability to cool off.”

According to Zach Schlader, a physiologist at Indiana University Bloomington, a wet-bulb temperature of 35°C (95°F)—a measure of heat and humidity combined—is the absolute limit of human tolerance.

Senthil Logesh, a 26-year-old construction worker from India employed in Singapore, noted that heat shelters and water stations had to be established at his worksite. In May, some parts of the city, known for its year-round humidity, experienced temperatures of 37°C (98.6°F), matching a record set four decades earlier. Despite monitoring wet-bulb temperatures and offering rest when necessary, Mr. Logesh, who works nearly ten hours daily, described how everyone remained persistently drenched in sweat.

Over the coming decades, Asia’s urban population is projected to double, primarily in tier-two cities in countries like Thailand, Indonesia, and Vietnam. Professor Chow, who co-chairs the Intergovernmental Panel on Climate Change (IPCC), emphasises the need to not only reduce emissions but also adapt to increasingly frequent and intense heatwaves.

“Not only will there be more construction taking place, but it will also happen in hotter conditions, so we need to start looking at reducing risks for many vulnerable people,” he said.

While wealthier Southeast Asian nations like Singapore have infrastructure to mitigate heat’s impact, such as air-conditioned malls and homes, the situation differs for poorer countries in the region. Even when heat mitigation plans exist, they are often underfunded and tend to overlook impoverished communities.

Thailand, for example, has a national-level early warning system for heatwaves that advises people to seek shelter or wear light-colored clothing.

“But not everyone can do that, such as homeless people, the disabled, or the elderly. The plans need to be tailored to these groups as well,” he said. “This is all assuming people actually do as they are told. These plans serve more as general recommendations than specific instructions.”

In India, the western city of Ahmedabad developed a low-budget strategy in 2013 following a deadly heatwave that claimed 1,344 lives. Authorities applied white paint to the tin and asbestos roofs of slum homes to cool them, and public parks remained open throughout the day to provide shade for street vendors and construction workers. However, critics argue that more comprehensive measures are needed to protect marginalised communities, who bear the brunt of natural disasters like heatwaves due to their limited means and lack of access to infrastructure.

In Nepal, Krishni Tharu, a 30-year-old construction labourer, finds herself sharing a single standing fan with her two children and mother-in-law on hot summer nights. Working in Nepalgunj, where temperatures reached 44°C (111°F) in June, she experiences grueling 10-hour workdays from dawn to dusk, earning approximately $4.50 per shift to support her family. As temperatures continue to rise each year, her physically demanding outdoor labor becomes increasingly challenging.

But she can’t stop. Cutting off her family’s precious income is not an option, she said. “There is no escape. I have to work.”