Study Highlights How Extreme Heat Threatens Tropical Bird Populations

A recent study involving Australian scientists reveals that climate change-driven heat extremes have caused a dramatic decline of 25-38% in tropical bird populations since 1950.

The research, released by the University of Queensland, found that while changes in average temperature and rainfall play a role, the most significant threat to tropical birds comes from exposure to extreme heat events. The study analyzed over 3,000 bird populations worldwide between 1950 and 2020, using weather data to differentiate climate impacts from human activities like habitat loss, based on a dataset of 90,000 observations across all continents.

Published in Nature Ecology & Evolution, the study confirms that extreme heat events have surged over the past 70 years, especially near the equator. Tropical birds now face dangerously hot days nearly ten times more often than before.

These heat extremes cause lasting harm to surviving birds, including organ failure and reduced breeding success. The intense heat affects body condition, limits foraging, stresses eggs and chicks, and leads to dehydration or nest abandonment.

Alarmingly, even birds in remote, protected tropical forests are experiencing population declines driven by heat, with climate change impacts outweighing direct human threats.

Since nearly half of all bird species live in tropical regions, these findings represent a major threat to global biodiversity. Scientists stress the urgent need for emission reductions and habitat conservation to protect these vulnerable species.

Meanwhile, the World Meteorological Organization (WMO) has highlighted how extreme heat is increasingly affecting millions worldwide, with wildfires and deteriorating air quality worsening the situation. WMO’s recent bulletin notes a rise in global heatwaves and record-breaking temperatures in many areas.

According to the EU’s Copernicus Climate Change Service, July 2025 ranked as the third-warmest July on record globally, with sea surface temperatures also near record highs. Arctic sea ice extent for July was the joint second-lowest in 47 years of satellite data, matching levels seen in 2012 and 2021.

In Europe, heatwaves heavily impacted Sweden and Finland, which experienced prolonged periods above 30°C. Southeast Europe also faced severe heat and wildfire outbreaks.

These findings underscore the critical need for climate action to safeguard both human and wildlife health amid escalating heat extremes worldwide.