Researchers at Oregon State University have analyzed data for 70,814 species and categorized them based on animal class and risks associated with climate change according to the International Union for Conservation of Nature's (IUCN) assessment.
At least one-quarter of species in six different classes are threatened by climate change, including spiders, centipedes, and coral animals.
So far, the main cause of loss of biological diversity has been overexploitation and changed living environments, but as climate change intensifies, we expect it to become a third major threat to the Earth's animals, says William Ripple, professor of ecology who led the study.
Vulnerable
The researchers are particularly concerned about invertebrate animals in the sea, which absorb most of the heat from climate change. Their limited ability to move and quickly avoid unfavorable conditions makes them extra vulnerable.
A 90 percent reduction in mollusk populations along Israel's coast due to rising water temperatures shows how sensitive invertebrate animals are, says Ripple.
But mass death is not limited to invertebrate animals: in 2015 and 2016, around four million sardines died off the coast of North America as the food chain was disrupted by an extreme marine heat wave.
The same heat wave caused a 71 percent reduction in Pacific cod – and heat waves at sea have likely contributed to around 7,000 whale deaths in the northern Pacific Ocean.
Limited Information
Another reason for concern of researchers is how little information has been collected about the risks climate change poses to wild animals. The 70,814 species analyzed correspond to only 5.5 percent of all species.
IUCN's Red List of endangered species also has a bias towards vertebrate animals, which make up less than six percent of the Earth's known species, notes Ripple.
We need a global database on mass mortality due to climate change for animal species in all ecosystems, and a faster assessment of species that are currently being ignored.
The study has been published in the journal Bioscience.
