The impact of climate change − attributed to human activities, in particular the burning of coal, oil, and methane gas − has become increasingly evident, with 48.6 million people in Indonesia experiencing extreme heat in the period from December 2024 to February 2025, a study by Climate Central reveals.

According to Climate Central’s report, Indonesia ranks as the second-most affected country after Nigeria, with 48.6 million people, or 17 percent of Indonesia’s population, exposed to extreme heat for over 30 days. Additionally, 45.1 million people, or 16 percent of the population, have suffered from high temperatures worsened by the climate crisis.

Capital Jakarta has been identified as the fourth-most affected megacity worldwide, following Lagos in Nigeria, Tamil Nadu in India, and Manila in the Philippines. The city has endured 69 days of extreme heat, with temperature anomalies reaching 0.7°C above historical averages.

Globally, 394 million people have experienced extreme heat for more than 30 days due to climate change, with 74 percent of them residing in Africa. Heat anomalies occur when temperatures exceed 90 percent of local records from 1991 to 2020, increasing health risks and heat-related mortality.

Climate Central scientist Joseph Giguere emphasized the average person worldwide experienced six days of extreme heat from December 2024 to February 2025, five of which were directly linked to human-induced climate change.

”Without global warming, people would have experienced only one day of high temperatures in the same period,” Giguere said as quoted in a statement on Thursday, March 20, 2025.

Beyond extreme heat, Indonesia has also faced increased rainfalls leading to flash floods in Java, resulting in 21 fatalities and the displacement of thousands.

Climate Central’s data show that of 220 countries analyzed, half experienced over a month of extreme heat due to climate change. Additionally, 287 major cities worldwide, including Jakarta, have endured prolonged exposure to extreme temperatures.

The ongoing rise in temperatures is primarily driven by the reliance on fossil fuels. Global temperatures have increased by approximately 1.2°C since the pre-industrial era due to the persistent burning of coal, oil, and methane gas.

“Climate change is no longer a distant threat but a present reality affecting millions,” Kristina Dahl, Vice President of Science at Climate Central, said.

“The rising frequency and intensity of heatwaves indicate a worsening trend unless fossil fuel combustion is significantly reduced,” she added.