PORTLAND, Ore. (KOIN) – A new study led by an Oregon State University researcher has revealed that more than 3,500 animal species are threatened by climate change.

The study, which was published Tuesday in the journal BioScience, details the “existential crisis” animals are facing because of climate change.

“We’re at the start of an existential crisis for the Earth’s wild animals,” said Oregon State University’s William Ripple, who led the study. “Up till now, the primary cause of biodiversity loss has been the twin threats of overexploitation and habitat alteration, but as climate change intensifies, we expect it to become a third major threat to the Earth’s animals.”

During the study, Ripple – a professor of ecology at OSU’s College of Forestry – and researchers in the U.S. and Mexico, analyzed animal data for more than 70,000 animal species.

From there, the team categorized the species by class and climate change risks as assessed by the International Union for Conservation of Nature, an organization made up of government and civil society groups advocating for conservation initiatives.

The researchers discovered that at least one-quarter of the species in six classes are threatened by climate change.

Those threatened include insect classes with spiders and scorpions, jellyfish and corals. Smaller percentages of other species are directly at risk from a warming climate, researchers said.

“We are particularly concerned about invertebrate animals in the ocean, which absorbs most of the heat from climate change,” Ripple explained. “Those animals are increasingly vulnerable because of their limited ability to move and promptly evade adverse conditions.”

Sudden impacts on animal communities can include mass mortality from extreme weather events including heat waves, wildfires, droughts and floods, researchers said.

“The cascading effects of more and more mass mortality events will likely affect carbon cycle feedbacks and nutrient cycling,” Ripple said. “Those effects also likely will have an impact on species interactions such as predation, competition, pollination and parasitism, which are vital for ecosystem function.”

Ripple pointed to a 90% decrease in mollusk populations along the coast of Israel because of warming water temperatures. This shows how susceptible invertebrates are to a warming climate, Ripple says.

There’s also examples closer to home, as Ripple pointed to the deaths of billions of intertidal invertebrates during the 2021 heat dome in the Pacific Northwest.

But these mass mortalities are not limited to invertebrates. In 2015 and 2016, around four million common murres off the U.S. west coast starved to death from an altered food web caused by an extreme marine heat wave, according to Ripple.

That heat wave also led to a 71% decrease in Pacific cod because of a rise in metabolic demand and reduced prey, Ripple said, adding marine heat waves have likely led to the deaths of about 7,000 humpback whales in the North Pacific.

According to the researchers, the analysis reveals “huge gaps” in fully understanding risks to the animal kingdom.

Ripple explained there’s a small amount of information being gathered on climate change risk for wildlife, noting 66 of 101 wildlife classes have not yet had any species assessed by the IUCN. The more than 70,000 species that have been assessed represent 5.5% of all described wildlife species that are alive, OSU said.

“Our analysis is meant to be a preliminary effort toward assessing climate risk to wildlife species,” Ripple said. “Understanding the risk is crucial for making informed policy decisions. We need a global database on mass mortality events due to climate change for animal species in all ecosystems, and an acceleration in assessing currently ignored species.”

The IUCN Red List of Threatened Species is also biased toward invertebrates, Ripple added, noting they make up less than 6% of the Earth’s named animal species.

“There is also a need for more frequent climate risk assessments of all species and better consideration of adaptive capacity,” Ripple said. “We need the integration of biodiversity and climate change policy planning on a global scale.”