by The world’s biggest capital cities are experiencing more hot days than ever, according to a new study, which says the dangerous trend is being driven by scorching temperatures across Asia as the climate crisis worsens.
The number of days above 35 degrees Celsius (95 degrees Fahrenheit) has increased by 52% over the past three decades in the world’s 20 most populous cities – home to more than 300 million people, according to analysis by the International Institute . for the Environment and Development (IIED) published on Friday.
From Buenos Aires, Argentina to the French capital Paris and Cairo, Egypt, the study found that over the past decade, as human-caused greenhouse gas emissions have increased, major cities have been recording days of extreme heat. hot more and more – threatening human health, economy. 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 one generation, there has been an alarming increase in the number of days of extreme heat affecting some of the world’s largest capital cities – exacerbated by the urban heat island effect,” which occurs when cities add roads and buildings natural land center. retain more heat.
Some of the biggest temperature rises have come in Asian cities, which comprise about half of the world’s most populous capital cities – a trend seen in recent heatwaves across the continent, from Southeast Asia to China and India. Asia is uniquely vulnerable to climate risks, due to its high population, poverty, and the proportion of people living in low-lying areas, prone to floods, sea level rise and other natural disasters.
New Delhi topped the list of hottest cities, recording 4,222 days above 35 degrees Celsius over the past three decades – more than any other city analysed. Between 2014 and 2023, just under half (44%) of days in the Indian capital reached that threshold, compared to 35% from 1994 to 2003, and 37% from 2004 to 2013.
The capital is only getting hotter. In late May, one part of Delhi reached 49.9 degrees Celsius (121.8 degrees Fahrenheit) – the city’s highest temperature on record, putting pressure on India’s electricity grid and power supply. The heat also lasted into the night, which left residents with little relief.
“We have lived in this neighborhood for 40 years, but we have never seen a summer like this,” Kalyani Saha, a 60-year-old resident of Lajpat Nagar in Southeast Delhi, told CNN.
“We only get water once a day, and it’s scalding hot, unless you fill a bucket and let it cool all day before you use it, you can’t bathe in this water.”
A Delhi rickshaw driver told CNN he was getting fewer passengers, with people opting for air-conditioned taxis instead of air transport.
“My body can’t take it, but I have to keep cycling,” said Sagar Mandal, 39. “We’re used to physical labor, we’re not complaining about that. But this heat is not normal, something has to change.”
Indonesia’s capital Jakarta saw one of the biggest jumps in the number of days above 35 degrees Celsius in the last 30 years, from 28 days between 1994 to 2003 to 167 days from 2014 to 2023.
Seoul, South Korea and Beijing, China have experienced significant increases during extremely hot days. In 2018, Seoul saw 21 days above 35 degrees Celsius – more than the previous 10 years combined. The number of days above 35 degrees in Beijing has increased by 309% since 1994.
Cities are also seeing longer periods of high temperatures, as governments fail to meet climate targets and curb emissions. In October 2023, Jakarta experienced 30 consecutive days over 35 degrees Celsius – more days than in the entire period between 1994 and 2003.
Extreme heat can be deadly, especially for vulnerable groups who do not have access to cool spaces. Between June 11 and 19, Delhi saw 192 deaths due to heat waves among its homeless population, the highest number on record compared to the same period in the past five years, according to a report by the NGO Center for Health Development India .
Young children, the elderly and pregnant people are at higher risk during heat waves, which can have a devastating effect on informal and hourly workers, who may have to stop work or choose between staying in the home without pay or working in dangerous conditions.
Heat also hurts economies, damages crops and livestock and reduces labor productivity, especially in places without air conditioning, as workers need more breaks to rest and rehydrate.
And extreme heat stresses infrastructure, including highways, roads, power lines and railroads, disrupting supply chains and blackouts and disease.
According to a Dartmouth College study in 2022, the global economy has cost the world a trillion dollars since the early 1990s, and the world’s poorest and most deprived countries are the most affected.
“Responding to the challenge of extreme heat will require bold action from policy makers, including serious investment to adapt to this new reality,” said Landesman, of the IED.
“For many cities, it’s not a lack of knowledge or capacity or resources that prevents large-scale action to address climate change, but a lack of political will and control tools.”
CNN’s Esha Mitra and Kathleen Magramo contributed reporting.
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