Scientists based in Europe and Australia have found that tropical bird populations have plummeted not only due to deforestation, but also extreme heat attributable to climate change, according to a study recently published in the journal Nature Ecology & Evolution.
The study said intensifying temperatures caused a 25-38 percent reduction in tropical bird populations between 1950 and 2020, compared to a scenario without manmade global warming.
Bird populations in the tropics now face 30 days of heat extremes per year, compared to only three per year in the mid-20th century, noted lead researcher Maximilian Kotz, a researcher at the National Supercomputing Centre in Barcelona and the Potsdam Institute for Climate Impact Research (PIK).
“This has major consequences for how we think about biodiversity conservation,” Kotz said. “Protecting pristine habitats is crucial, but without dealing with climate change, it won’t be enough for birds.”
Nearly half of all bird species are found in biodiversity-rich tropical regions, but many such birds may already be “close to the limits” of their tolerance to high temperatures, which can cause heatstroke (hyperthermia) or dehydration.
Extreme heat waves, which are becoming more frequent, represent a far greater threat than increases in average temperatures or rainfall, another result of human-induced climate change.
Until now, it has been widely assumed that the decline in bird populations worldwide was due mainly to other well-identified factors, especially habitat loss, pesticide use, hunting, and invasive species. But the new findings “challenge the view that direct human pressures have so far been the dominant driver of impacts on bird populations compared to climate change in tropical regions,” according to the authors.
This additional threat brought about by human-induced climate change underscores the importance of our efforts to mitigate it, because if it can impact bird populations, humans should also be at risk, especially the underprivileged who are in vulnerable areas and do not have access to amenities like air conditioning, or even basic medical care.
If we heed these warnings that our planet and its other occupants are telling us, and act accordingly and urgently while we still can, the human race may be able to avoid the same fate.*
