30% of species could be abruptly lost at 2.5°C of warming

Climate change is likely to abruptly push species over tipping points as their geographic ranges reach unforeseen temperatures, finds a new study led by a UCL researcher.

The researchers found that the extent of global warming makes a big difference: if the planet warms by 1.5°C, 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, but this doubles to 30 per cent of species at 2.5°C of warming.

The new Nature Ecology & Evolution study predicts when and where climate change is likely to expose species across the globe to potentially dangerous temperatures, according to a press statement issued here.

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The research team from UCL, University of Cape Town, University of Connecticut and University at Buffalo analysed data from over 35,000 species of animals (including mammals, amphibians, reptiles, birds, corals, fish, whales 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 – that is, the research projects that for many species there could be an abrupt loss of habitat due to future climate change.

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 researchers 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.

Lead author Dr Alex Pigot, UCL Centre for Biodiversity & Environment Research, UC Biosciences) said: “It is unlikely that climate change will gradually make environments more difficult for animals to survive in. Instead, for many animals, large swathes of their geographic range are likely to become unfamiliarly hot in a short span of time.”