The world’s biggest capital cities are heating up – and Asia tops the charts

Hong Kong CNN —

The world’s largest capital cities are seeing more extremely 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 world’s 20 most populous cities – together home to more than 300 million people – have seen a 52% jump in the number of days 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 the French capital Paris and Egypt’s Cairo, the study found with each passing decade, as human-caused greenhouse gas emissions rise, major capital cities are recording more and more extremely hot days – posing threats to human health, economies and infrastructure.

“Climate change is not 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’s been an alarming increase in the number of days of extreme heat affecting some of the world’s biggest capital cities — made worse by the urban heat island effect,” which occurs when cities replace natural land with roads and buildings that retain more heat.

Tourists shield themselves from the sunshine while visiting the Palace Museum during the Dragon Boat Festival holiday on June 9, 2024 in Beijing, China. Beijing Meteorological Observatory issued the first yellow alert for high temperatures in 2024, with the highest temperature in the city reaching 35 degrees Celsius.

Asian cities, which make up about half of the world’s most populous capitals, saw some of the biggest temperature