Pekanbaru to Surabaya Face Extreme Humid Heat Threat Due to Climate Crisis

A number of major Indonesian cities have been listed among the regions with the highest number of extreme humid heat days globally. This condition signals that urban areas in the country are increasingly vulnerable to the impacts of the climate crisis, which could potentially disrupt public health.

A new report from Climate Central, titled ‘Global Analysis: Dangerous Humid Heat Rising Due to Climate Change’, records that at least 10 Indonesian cities are among the top 50 cities worldwide with the most extreme humid heat days during the 2016-2025 period. Three of these cities are in the top 10, namely Pekanbaru with 353 days, Medan with 342 days, and Surabaya with 313 days.

In addition to these three cities, Jakarta, South Tangerang, and Tangerang also recorded high figures. These three areas experienced 290 days of extreme humid heat throughout 2016-2025, with 210 days, or approximately 72 percent, directly attributed to climate change. This figure is only surpassed by Makassar, which recorded 229 climate change-driven days out of a total of 287 extreme humid heat days.

Climate Central explains that tropical regions are the areas experiencing the most significant increase in extreme humid heat days in recent decades. This condition is influenced by rising global temperatures due to greenhouse gas emissions, which are making hot weather and high humidity more frequent.

Bondan Andriyanu, Manager of Outreach and Advocacy at CERAH, stated that these findings serve as a warning that urban communities face growing health risks from extreme heat. According to him, the threat comes not only from rising temperatures but is also exacerbated by air pollution, which remains a problem in many major cities.

‘This event is a reminder that the risk of extreme heat is real and has the potential to threaten lives, especially for those who work outdoors. In big cities like Jakarta, this threat is even greater because people are also exposed to air pollution,’ Bondan said. He assessed that reducing emissions from fossil fuel use must be a priority, as it not only helps slow the rate of climate change but also protects the health of people in urban areas.

Climate Central defines a dangerous humid heat day as a condition when the wet-bulb temperature reaches at least 25 degrees Celsius. Under such conditions, the body’s ability to cool itself through sweat evaporation decreases, increasing the risk of dehydration, heat exhaustion, cardiovascular and respiratory disorders, and even heat stroke.