The world’s largest capitals are experiencing more extreme heat days than ever before, a dangerous trend driven by scorching temperatures in Asia as the climate crisis worsens, according to a new study.
The world’s 20 most populous cities (home to more than 300 million people combined) have seen a 52% increase in the number of days with temperatures exceeding 35 degrees Celsius (95 degrees Fahrenheit) over the past three decades, according to an analysis by the International Institute. for Environment and Development (IIED) published on Friday.
From Buenos Aires, Argentina to Paris, France, and Cairo, Egypt, major capital cities are increasingly recording extremely hot days as human-caused greenhouse gas emissions increase with each passing decade, posing a threat to human health and economies, the study found. revealed that it created . and infrastructure.
“Climate change isn’t just a future threat; it’s already happening and getting worse,” IIED senior researcher Tucker Landesman said in a press release.
“In just one generation, there has been an alarming increase in the number of extremely hot days affecting some of the world’s largest capitals. This has been exacerbated by the urban heat island effect, which occurs when cities replace natural landscapes with roads and buildings that retain more heat.”
Asian cities, which account for about half of the world’s most populous capitals, have seen some of the largest temperature increases, a trend evident in recent heatwaves across the continent from Southeast Asia to China and India. Asia is uniquely vulnerable to climate risks because of its high population, poverty, and the proportion of people living in low-lying areas that make it prone to flooding, sea level rise, and other natural disasters.
New Delhi tops the list of hottest cities by recording 4,222 days above 35 degrees Celsius in the last three decades – more than any other city analysed. Between 2014 and 2023, almost half (44%) of days in the Indian capital met this threshold, compared with 35% between 1994 and 2003 and 37% between 2004 and 2013.
The capital region is getting hotter. In late May, part of Delhi reached 49.9 degrees Celsius (121.8 degrees Fahrenheit) – the city’s highest temperature on record, straining India’s electrical grid and power supply. The heat continued into the night, leaving little opportunity for residents to relax.
“We have been living in this neighbourhood for 40 years but we have never seen a summer like this,” Kalyani Saha, 60, who lives in Lajpat Nagar in southeast Delhi, told CNN.
“We only get water once a day and it’s so hot you can’t bathe in it unless you fill a bucket and let it cool before using it all day.”
A rickshaw driver in Delhi told CNN that the number of passengers has decreased as people are opting for air-conditioned taxis instead of open-air transport.
“My body can’t handle it but I have to keep cycling,” said Sagar Mandal, 39. “We are used to physical labor, we do not complain about it. “But this temperature is not normal, something needs to change,” he said.
Indonesia’s capital Jakarta has seen one of the biggest jumps in the number of days above 35 degrees Celsius in the past 30 years, from 28 days between 1994 and 2003 to 167 days between 2014 and 2023.
Seoul, South Korea, and Beijing, China also saw significant increases in extremely hot days. In 2018, Seoul saw 21 days with temperatures above 35 degrees Celsius, more than in the previous 10 years combined. Beijing’s number of days above 35 degrees Celsius increased by 309% since 1994.
Cities are also seeing longer periods of high temperatures as governments fail to meet climate targets and cut emissions sufficiently. In October 2023, Jakarta experienced 30 consecutive days above 35 degrees Celsius – more days than in the entire period between 1994 and 2003.
Extreme heat can be deadly, especially for vulnerable groups who lack access to cool spaces. According to a report by the NGO India Centre for Health Development, there were 192 heatwave-related deaths among the homeless population in Delhi between June 11 and 19, a record high compared with the same period in the past five years.
Young children, the elderly and pregnant women are at higher risk during heatwaves; this can also have a devastating impact on informal and hourly workers, who may face work cuts or be forced to choose between staying home without pay or working in dangerous conditions.
Hot weather also hurts the economy, damaging crops and livestock and reducing labor productivity as workers need more breaks to rest and drink water, especially in places without air conditioning.
Extreme temperatures strain infrastructure including highways, highways, power cables and railways, causing supply chain disruptions, power outages and illnesses.
Extreme heat has cost the global economy trillions of dollars since the early 1990s, with the world’s poorest and lowest-emitting countries bearing the brunt of the impact, according to a 2022 study from Dartmouth College.
“Addressing the extreme heat challenge will require bold action by policymakers, including significant investments to adapt to this new reality,” IIED’s Landesman said.
“For many cities, what prevents large-scale action to combat climate change is not a lack of knowledge, capacity or resources, but a lack of political will and management tools.”
CNN’s Esha Mitra and Kathleen Magramo also contributed reporting.
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