Research Reveals Effects of Extreme Heat on Tropical Bird Populations

A study led by Australian scientists reveals that climate change-driven heat extremes have wiped out 25-38% of tropical bird populations since 1950.

The research, published by the University of Queensland, shows that while shifts in average temperature and rainfall affect bird populations, the greatest threat comes from extreme heat events. Researchers analyzed data from over 3,000 bird populations globally between 1950 and 2020, using weather and habitat data to distinguish the impact of climate from human activities like habitat loss.

Published in Nature Ecology & Evolution, the study confirms that extreme heat events near the equator have increased dramatically over the past seven decades. Tropical birds now face dangerously hot days almost ten times more frequently than before.

These heatwaves cause severe stress to birds, leading to organ failure, decreased breeding success, limited foraging, dehydration, and nest abandonment. Even birds in remote, protected tropical forests are experiencing declines, indicating that climate change effects outweigh direct human pressures.

With nearly half of the world’s bird species found in tropical regions, the study signals a major threat to global biodiversity, urging urgent emissions reductions and stronger habitat protection. Simultaneously, the World Meteorological Organization (WMO) warns that extreme heat is affecting millions of people worldwide, exacerbated by wildfires and poor air quality. WMO’s August 7 bulletin highlights increasingly frequent heatwaves and record temperatures across many regions.

According to the EU-funded Copernicus Climate Change Service, July 2025 was the third-warmest July on record, with sea surface temperatures also near historic highs. Arctic sea ice extent for July tied for the second-lowest in 47 years of satellite records.

In Europe, heatwaves particularly affected Sweden and Finland, with prolonged temperatures above 30°C, while Southeast Europe faced heatwaves and wildfires.

These findings emphasize the urgent need for global climate action to protect both ecosystems and human health amid rising heat extremes.