A new study has found that nearly half (47%) of the mammals and nearly a quarter (24.4%) of the birds on the IUCN Red List of threatened species are negatively impacted by climate change: a total of about 700 species. Previous assessments had said only 7% of listed mammals and 4% of birds were impacted.
“Many experts have got these climate assessments wrong in some cases, massively so,” said Dr. James Watson of the University of Queensland and the Wildlife Conservation Society, who co-authored the paper with scientists in the UK, Italy and the U.S.
“Species’ traits influenced their response to climate change,” published last week in the Nature Climate Change journal, contains analysis of 130 studies reported between 1990 and 2015, paints a grim picture of the impact of the changing climate on birds and mammals already under threat.
Most researchers tended to assess the impact of climate change on one species or ecosystem, and often cast forward 50 or 100 years, ignoring the fact the climate is already altered, said Watson. “I think that’s a real problem with how the scientific community has communicated the issue, because people are always labeling it as a future threat. When you combine the evidence, the impact on species is already really dramatic.”
Some species were more vulnerable than others, with elephants and primates’ ability to adapt to changing conditions curtailed by their slow reproductive rates. Rodents that could burrow to escape extreme environments would be less impacted.
Mammals with specialized diets were “already far more affected” than others, as were species of birds living at high altitudes. Animals found in tropical and subtropical forests under an existing threat of habitat degradation faced additional challenges from climate change.
Watson said many assessments of red listed species had assumed that hunting, deforestation and loss of habitat posed greater and more immediate risk than climate change.
“Many risk assessments are simply blind to the fact that climate change is happening now. If you read a scientific paper on climate change and species, it’s always that things will get worse in the future, not that it’s happening now.”
Governments need to act urgently to lessen the impact of climate change by slowing its progress by drastically reducing emissions and strengthening the reliance of species and ecosystems, said Watson.