Study Reveals Impact Of Heat Extremes On Tropical Birds' Populations

Climate change-driven heat extremes have wiped out 25-38 per cent of tropical bird populations since 1950, according to a study involving Australian scientists.

The study found that while shifts in average temperature and rainfall have some influence, the biggest climate threat to birds, particularly in tropical regions, comes from exposure to extreme heat, according to an analysis released Tuesday on the University of Queensland website.

Australian and European researchers analysed over 3,000 bird populations from 1950-2020, using weather data to separate climate impacts from human pressures such as habitat loss, in a dataset of 90,000 observations from all continents, it said.

The research, published in Nature Ecology & Evolution, confirmed the work of other climate scientists showing extreme heat events have increased dramatically over the past 70 years, especially near the equator, Xinhua News Agency reported.

Birds in tropical regions are now experiencing dangerously hot days about ten times more often than they did in the past, researchers have found.

Surviving birds may suffer lasting damage, including organ failure and reduced breeding success, as extreme heat lowers body condition, limits foraging, stresses eggs and chicks, and can cause dehydration or nest abandonment, the study showed.

Researchers warned that even remote, protected tropical forests untouched by humans are seeing heat-driven bird declines, with climate impacts outweighing direct human pressures.

Given that nearly half of all bird species are found in tropical regions, the findings signal a major threat to global biodiversity and urge urgent emission cuts and habitat protection to conserve species.

Meanwhile, the World Meteorological Organisation (WMO) has warned that extreme heat is impacting millions of people around the world, with wildfires and poor air quality compounding the problem, highlighting the importance of early warning and heat-health action plans.

WMO issued a bulletin on August 7, stating that data from its members show increasingly frequent global heatwaves and record-breaking temperatures in many regions.

According to the EU-funded Copernicus Climate Change Service, July 2025 was the third-warmest July globally (after July 2023 and July 2024).

The average sea surface temperature was also the third-highest on record. Arctic sea ice extent ranked joint second-lowest for July in the 47-year satellite record, virtually tied with 2012 and 2021.

In July, within Europe, heatwave conditions particularly affected Sweden and Finland, which experienced an unusually long spell of temperatures above 30 degrees Celsius. Southeast Europe also faced heatwaves and wildfire activity.

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