- Researchers found 2% of amphibian species are already experiencing temperatures beyond their physiological limits, potentially increasing to 7.5% with continued climate warming.
- The study revealed an unexpected pattern where tropical species in the Southern Hemisphere face greater heat risk, while in the Northern Hemisphere, species at higher latitudes are more vulnerable.
- Habitat plays a crucial role in vulnerability, with aquatic species facing the lowest risk, tree-dwelling species at moderate risk, and ground-dwelling species experiencing the highest risk of overheating.
- Conservation efforts should focus on maintaining water bodies and shaded areas, as these serve as critical thermal refuges that can help amphibians survive extreme heat events.
For about 2% of the world’s amphibian species, it’s already getting too hot to survive in their natural habitats, according to a new study in Nature. If the planet keeps warming unchecked, this number is expected to jump to 7.5% by the end of the century.
“We found that currently, about 100 species [104 out of 5,203 studied] are likely experiencing overheating events right now, where environmental temperatures exceed their physiological heat limits,” study co-author Alex Gunderson, an ecologist at Tulane University in the U.S., told Mongabay.
Amphibians are an incredibly important part of the food web, Gunderson said. “They’re sort of the potato chips of the forest in many of these ecosystems where they serve as food for birds and bats and mammals and fish.”
They also eat things that transmit diseases, including mosquitoes, so their loss can affect human health. For instance, a 2020 study showed that the decline of amphibians in Central America was linked to an increase in malaria.
The new research, led by scientists from the University of New South Wales in Australia, gives the most complete picture yet of how climate change affects the ability of amphibians such as frogs and salamanders to regulate their body temperature.
The scientists used actual heat tolerance data for 524 species and then statistical methods to generate estimates for more than 5,000 species, representing approximately 60% of all known amphibian species worldwide.
“There are only a few hundred species where people have actually taken the animals and warmed them up and looked at what their heat limits are,” Gunderson said. But don’t worry. These tests aren’t fatal to the animals.
“You warm them up and flip them on their back and they’ll flip themselves back over,” Gunderson said. Eventually, they can’t do that anymore, showing that “they essentially lose neuromuscular coordination. But they don’t die…They cool down and they’re fine.” (The human equivalent might be like getting dizzy after staying in a sauna or hot spring for too long.)
Using the “hot frog” data, the study asks: Where are amphibians most vulnerable to climate change?
The research team found certain “hotspots” where many amphibians are overheating, including the southeastern United States, Northern Australia, and the Amazon Rainforest.
Where amphibians live in the landscape also plays a big role in their chances of survival. For example, those that are primarily aquatic have the lowest overheating risk. But species living on the ground have the highest risk. The environment tends to be warmer near the ground, so arboreal species, those that spend most of their time up in trees, are also at lower risk overall.
The researchers found something unexpected, Gunderson said: They predicted that species living closer to the equator, in tropical regions, should generally be more vulnerable to climate warming than those in temperate regions. Yet this was true only in the Southern Hemisphere.
In the Northern Hemisphere, they found the opposite pattern. There, amphibians living at higher latitudes, or further from the equator, showed greater vulnerability to heat stress than their tropical counterparts. Gunderson said they don’t yet have a definitive explanation for this pattern.
The study also found a dangerous turning point between 2° and 4° Celsius (3.6° and 7.2° Fahrenheit) of warming, with many more species expected to suffer as temperatures increase. “As the average temperature gets closer to the threshold, you just get so many more days when the temperatures exceed the thermal limits,” Gunderson said.
The researchers point out that their estimates are on the conservative side, since they assumed amphibians can find shade. “Therefore, the impacts of global warming will likely exceed our projections,” said lead author Patrice Pottier, a researcher at the University of New South Wales.
According to a UN report, the world is currently on track for 4°C of warming by 2100 without drastic reductions in fossil fuel emissions.
Rayna C. Bell, curator of herpetology at the California Academy of Sciences, who wasn’t involved in the study, told Mongabay this research may help scientists decide where to focus their conservation work.
Studies like this, “can be really helpful for identifying which species might be most at risk even though they haven’t been studied yet,” as well as to “triage where we can have the greatest impact with future research and conservation management efforts,” Bell said.
The study concludes that conservation efforts should protect amphibians’ habitats, especially dense vegetation cover for shade and water bodies.
“We found that if you provide amphibians with enough water and enough shade, a lot of them can survive extreme heat events,” Pottier said. “We must protect and restore the environments that allow them to regulate their body temperature.”
Banner image of a male Holy Cross frog (Notaden bennettii) from Australia. Photo courtesy of Peter Soltys.
Liz Kimbrough is a staff writer for Mongabay and holds a Ph.D. in Ecology and Evolutionary Biology from Tulane University, where she studied the microbiomes of trees. View more of her reporting here.
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Citations:
Pottier, P., Kearney, M. R., Wu, N. C., Gunderson, A. R., Rej, J. E., Rivera-Villanueva, A. N., … Nakagawa, S. (2025). Vulnerability of amphibians to global warming. Nature, 639(8056), 954-961. doi:10.1038/s41586-025-08665-0
Springborn, M. R., Weill, J. A., Lips, K. R., Ibáñez, R., & Ghosh, A. (2020). Amphibian collapses increased malaria incidence in Central America. Environmental Research Letters, 17(10), 104012. doi:10.1088/1748-9326/ac8e1d
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