Climate change may be harming far more of the world's threatened species than previously thought. A new study suggests that nearly half of the mammals and a quarter of the birds on the International Union for the Conservation of Nature's "red list" have already become victims of a shifting climate.

The research, published this week in the journal Nature Climate Change, concludes that scientists and wildlife conservationists have failed to account for the damage inflicted by global warming.

"Our results clearly show that the impact of climate change on mammals and birds to date is currently greatly under-estimated and reported upon," co-author James Watson, of the Wildlife Conservation Society and the University of Queensland in Australia, said in a statement. "We need to greatly improve assessments of the impacts of climate change on species right now, we need to communicate this to the wider public and we need to ensure key decision-makers know that something significant needs to happen now to stop species going extinct.

"Climate change is not a future threat anymore."

The authors, part of an international team of academics and conservationists, reviewed 130 previous studies on nearly 700 bird and mammal species and chronicled whether climate change had harmed, benefited or had no discernible effect on the creatures.

They then identified characteristics that appeared to make species more vulnerable to climate change and extrapolated their findings to all the birds and mammals listed as threatened by the International Union for the Conservation of Nature.

According to their analysis, climate change has likely already harmed 47 percent of terrestrial mammals and 23 percent of birds listed. The IUCN lists climate change as a threat to only 7 percent of those mammals and 4 percent of the birds.

The review found that mammals that burrow into the earth, for example, can protect themselves from extreme heat and tend to be more resilient. Rodents and insectivores on the list seem to have benefited more than they've been harmed.

But members of nine other orders of mammals have not fared so well. Primates, marsupials and elephants have likely been hit hard by climate change, the authors wrote. They live primarily in tropical or sub-tropical zones, meaning they've evolved within a narrow range of temperatures. Primates' and elephants' slow reproductive rates also make it harder for them to adapt to rapid environmental changes.

Among birds, species living at high altitudes are particularly at risk. Aquatic birds and those inhabiting tropical forests are also more likely to be harmed, with their habitats particularly threatened by fragmentation.

The authors noted several uncertainties and limitations to their work. Animals in Europe and North America were studied far more than those on other continents, so the findings "might be less generalizable" to creatures in Africa, Asia and South America.

"Despite these uncertainties, our results suggest that the impact of climate change on mammals and birds in the recent past is currently greatly underappreciated," the paper said. "We recommend that research and conservation efforts give greater attention to the 'here and now' of climate change impacts on life on Earth."