John J. Wiens/University of Arizona

Hundreds of Earth's creatures are at risk of extinction due to climate change: By 2070, we could lose almost half of all animal and plant species -- depending upon human response to the warming planet -- according to a new study from the University of Arizona.

The study, published in the Proceedings of the National Academy of Sciences journal, examined 538 species and 581 sites worldwide, focusing on the same species found at the same sites at least 10 years apart. Researchers gathered climate data from the time of the earliest survey of each site and the most recent. Some 44 percent of the 538 species had already gone extinct at one or more sites, the study found.

Extinctions occurred more often at locations that hit maximum annual temperatures (so hottest daily highs) as opposed to those with smaller changes in average yearly temperature, according to the study.

Species loss will ultimately depend on how humans combat climate change, and how much the planet warms in the future.

"In a way, it's a 'choose your own adventure,'" John J. Wiens, study co-author and professor in the Department of Ecology and Evolutionary Biology at University of Arizona, said in a press release. "If we stick to the Paris Agreement to combat climate change, we may lose fewer than two out of every 10 plant and animal species on Earth by 2070. But if humans cause larger temperature increases, we could lose more than a third or even half of all animal and plant species, based on our results."

In May 2019, a United Nations-backed report compiled by 145 experts from across the globe found that up to 1 million plant and animal species are threatened with extinction within decades.