South and Southeast Asia’s heat waves are a grim sign of the times

A severe heat wave unfurled across a wide swath of Asia. From India to the Philippines, officials in various municipalities shuttered schools and urged locals to stay home and ward against signs of heat-induced fatigue. Scorching temperatures melted roads in Bangladesh, and numerous voters fainted as they lined up at polling stations for advance voting in Thailand’s election. High temperatures are expected to last through the end of the month, as climate scientists and researchers point to the mounting evidence of what human-induced climate change is doing to our planet.

By some measures, Asia just experienced its hottest April on record. Globally, the past eight years have been the eight warmest on record. Experts warn that the warming temperatures will make deadly heat waves both more frequent and longer-lasting events. The current wave through Southeast Asia may be linked to another possible impact of climate change, with shifts in the hydrologic cycle leading to suppressed rainfall in parts of the region over the winter. “Because dry soil heats up faster than moist soil, a hot anomaly naturally forms as spring arrives,” explained Koh Tieh Yong, a climate scientist at the Singapore University of Social Sciences, to Bloomberg News.

“Approximately 18.3 percent of Laotians live in poverty, and are far more likely to be harmed by elevated temperatures,” noted my colleague Matthew Cappucci. “It’s likely that significant excess mortality — or premature deaths caused by the intersection of heat stress and preexisting vulnerabilities — is occurring across Southeast Asia.”

He cited the tweets of Maximiliano Herrera, a climate historian who tracks temperature records and who wrote that the recent wave was “one of the most brutal heat event[s] the world has ever witnessed.”

What it’s like to toil in India’s dangerous, unrelenting heat

For much of the world, and especially in many countries in Asia, these hot months are a grim augur of things to come. Not only are daytime temperatures breaking records, but so too the measurements after sunset, adding to the misery of countless people seeking respite from the sweltering conditions. India, the world’s most populous country, is also one of the world’s countries most vulnerable to climate change. It experienced a record-breaking set of heat waves last year, while this year it saw its hottest February in 122 years. Temperatures neared record levels in recent weeks, with dozens dying due to the conditions.

While the country is accustomed to extreme heat, experts fear the combined effects of spiking temperatures and the potential return of the weather pattern known as El Niño may wreak significant damage. “The health department as well as the disaster-management authority, I think, have not thought through what the impacts might be to people if the heat worsens later this year,” Dileep Mavalankar, director of the Gujarat-based Indian Institute of Public Health, to the South China Morning Post. “If El Nino disrupts India’s monsoon season, there will be a deficit of rain and, of course, this will hugely impact agriculture and farming, and, as a result, the economy.”

Recent research also suggests that India’s combination of high heat and humidity is pushing its population to struggle in circumstances beyond the literally perilous “wet bulb” threshold — that is, the estimation that above 35 degrees Celsius, the human body can no longer adequately cool itself through perspiration. In these conditions, brain damage and heart and kidney failure are more common.

“The Indo-Gangetic Plain is one of the few places where such wet-bulb temperatures have been recorded, including on several occasions in the scorched Pakistani town of Jacobabad,” detailed the Economist. “A report by the World Bank in November warned that India could become one of the first places where wet-bulb temperatures routinely exceed the 35 degree Celsius survivability threshold.”

A future of more extreme heat has other measurable impacts. “Estimates show a 15 percent decrease in outdoor working capacity … during daylight hours due to extreme heat by 2050,” a study published in the journal PLOS Climate reported, laying out projections specifically for India. “The increased heat is expected to cost India 2.8 percent and 8.7 percent of its Gross Domestic Product (GDP) and depressed living standards by 2050 and 2100, respectively.”

What extreme heat does to the human body

Away from Asia, the situation isn’t much better. The past month saw temperature records fall on both sides of the Strait of Gibraltar, with Spain coping with perhaps its worst drought in a century. An epochal drought in the Horn of Africa has directly impacted some 50 million people in the region and is the bleak subtext lurking behind a morass of armed conflicts.

And the phenomena provoked by climate change may only be accelerating. A study published Monday found that a major glacier in Greenland is melting much faster than anticipated, prompting speculation that current projections for sea level rise may be too conservative. “Overall the new study again underscores that we don’t really know how quickly one of the largest consequences of climate change — sea level rise from the melting ice sheets of Greenland and Antarctica — will occur,” wrote my colleague Chris Mooney. “We’re still finding out new details — and new reasons to think that it could be faster than expected.”