The scientists examined data from over 35,000 species from every continent in the context of four different climatic future forecasts and discovered that at 1.5°C of warming, around 15% of species will be abruptly lost, increasing to 30% of these species at 2.5°C of warming
A new study published in Nature Ecology & Evolution predicts when and where climate change will expose species around the world to potentially lethal temperatures. The researchers from UCL, the University of Cape Town, the University of Connecticut, and the University of Buffalo examined data from over 35,000 animal species and seagrasses (including mammals, amphibians, reptiles, birds, corals, fish, whales, and plankton) from every continent and ocean basin, as well as climate projections up to 2100.
The researchers discovered a continuous trend in which many animals' thermal exposure thresholds will be crossed across a large portion of their geographic range within the same decade.
The researchers investigated when areas within each species’ geographical range will cross a threshold of thermal exposure, defined as the first five consecutive years where temperatures consistently exceed the most extreme monthly temperature experienced by a species across its geographic range over recent history (1850-2014). Once the thermal exposure threshold is crossed, the animal is not necessarily going to die out, but there is no evidence that it is able to survive the higher temperatures – that is, the research projects that for many species there could be an abrupt loss of habitat due to future climate change.
The scientists found that the extent of global warming makes a big difference: if the planet warms by 1.5°C, 15% of species they studied will be at risk of experiencing unfamiliarly hot temperatures across at least 30% of their existing geographic range in a single decade, but this doubles to 30% of species at 2.5°C of warming. Lead author Alex Pigot (UCL Centre for Biodiversity & Environment Research, UCL Biosciences) remarked, “Our study is yet another example of why we need to urgently reduce carbon emissions to mitigate the harmful effects climate change is having on animals and plants, and avoid a massive extinction crisis.”
He added, Our findings suggest that once we start to notice that a species is suffering under unfamiliar conditions, there may be very little time before most of its range becomes inhospitable, so it’s important that we identify in advance which species may be at risk in coming decades.”
Co-author Christopher Trisos (African Climate and Development Initiative, University of Cape Town) said, “In the past we’ve had snapshots to show the impact of climate change, but here we are presenting the data more like a movie, where you can see the changes unfold over time. This shows that for many species the risk is more like everything, everywhere, all at once. By animating this process, we hope to help direct conservation efforts before it’s too late, while also showing the potentially catastrophic consequences of letting climate change continue unchecked.”
According to the researchers, this pattern of rapid exposure is an unavoidable feature of life on a round planet since, due to the shape of the Earth, there is greater area available to species in habitats near the hot end of what they are acclimated to, such as low-lying areas or around the equator.
They discovered that many species confronting unexpected temperatures will be living with other creatures suffering comparable temperature shocks in another study, which could pose serious dangers to local ecosystem function.