If global warming exceeds 1.5 degrees Celsius above the average pre-industrial global temperature, significant portions of the world’s wildlife could suffer habitat loss, warns a new study. Although species around the world would be at risk, those in Southern Africa, the Amazon, Europe and Australia are especially vulnerable.
The 2015 Paris Agreement seeks to limit global warming to less than 2°C, with an ultimate goal of keeping it at or below 1.5°C. However, even with current pledges to cut carbon, global temperature would rise by about 3.2°C.
Compared to 2°C, limiting warming to 1.5°C would avoid two-thirds of the risks global warming poses to insects and half the risks to plants and animals, according to the new study.
Led by the University of East Anglia in the United Kingdom, the study analyses how different levels of warming would impact the ranges of 115,000 species, making it the most comprehensive research of its kind to date. The study, published on Thursday in Science, used data from the open access database Global Biodiversity Information Facility and included around 31,000 insects, 8,000 birds, 1,700 mammals, 1,800 reptiles, 1,000 amphibians and 71,000 plants.
“We wanted to see how different projected climate futures caused areas to become climatically unsuitable for the species living there,” Professor Rachel Warren, from the Tyndall Centre for Climate Change Research at University of East Anglia, said in a statement.
In order to measure the risks to biodiversity, the team tallied the number of species expected to lose more than half their geographic range as a result of climate change.
All plants, animals and insects have a range of climates where they can comfortably survive, Warren explained to the Los Angeles Times. “Outside of that range, it gets a little bit uncomfortable, and eventually gets to where it can’t survive at all.”
The results showed that insects are particularly vulnerable to climate change. With 2°C of warming, 18% of the 31,000 insects included in the study would lose half there range, while 3°C would result in 50% of the insects losing half their range.
If the average global temperature rise reaches two degrees higher than pre-industrial levels, 16% of plants and 8% of vertebrates would be expected to lose more than half their geographical range, according to the findings. If warming is kept at 1.5°C, only 8% of plants, 6% of insects and 4% of vertebrates are projected to lose more than half their geographical range.
However, if temperature rise reaches 3°C, as can be expected with current pledges to reduce emissions, nearly half of plants and more than a quarter of vertebrates would lose over half of their geographical range.
“The takeaway is that if you could limit warming to 1.5 degrees, the risk to biodiversity is quite small. At 2 degrees it becomes significant, and at 3 degrees almost half the insects and plants would be at risk,” Warren told the Los Angeles Times
Researchers said that reducing the risk to insects is especially important given the vital role they play in ecosystems. Insects are essential for a variety of ‘ecosystem services,’ including pollinating crops and flowers, helping to recycle nutrients in the soil and serving as a food source for animals higher up in the food chain.
“The disruption to our ecosystems if we were to lose that high proportion of our insects would be extremely far-reaching and widespread,” Warren told The Guardian. “People should be concerned – humans depend on ecosystems functioning.”