Climate change to push 30% species over tipping points: Study

Climate change is likely to abruptly push up to 30 per cent species over tipping points as their geographic ranges reach unforeseen temperatures, according to a study. The researchers found that if the planet warms by 1.5 degrees Celsius, 15 per cent of species they studied will be at risk of experiencing unfamiliarly hot temperatures across at least 30 per cent of their existing geographic range in a single decade. However, this doubles to 30 per cent of species at 2.5 degrees Celsius of warming, they said. The study, published in the journal Nature Ecology & Evolution, analysed data from over 35,000 species of animals -- including mammals, amphibians, reptiles, birds, corals, fish, cephalopods and plankton -- and seagrasses from every continent and ocean basin, alongside climate projections running up to 2100.

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, according to the researchers. They found a consistent trend that for many animals, the thermal exposure threshold will be crossed for much of their geographic range within the same decade. "It is unlikely that climate change will gradually make environments more difficult for animals to survive in. Instead, for many animals, large swaths of their geographic range are likely to become unfamiliarly hot in a short span of time," said study lead author Alex Pigot from University College London (UCL) in the UK.

"While some animals may be able to survive these higher temperatures, many other animals will need to move to cooler regions or evolve to adapt, which they likely cannot do in such short timeframes," Pigot said in a statement. The study suggests that once a species is suffering under unfamiliar conditions, there may be very little time before most of its range becomes inhospitable."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," Pigot added.