Study: Holding global warming to 2.75 degrees Fahrenheit saves most species
(CNS) The world’s nations can protect the vast majority of plant and animal species from climate change by limiting global warming to 2.7 degrees Fahrenheit by 2100, a new study finds.
The report, published Thursday in the journal Science, is the first to examine how species across the globe would benefit from restricting global warming to 2.7 degrees Fahrenheit above pre-industrial averages – the lower limit for temperature as outlined in the 2015 Paris climate agreement.
The findings suggest that meeting this goal would avoid half the risks associated with warming of 3.6 degrees Fahrenheit – the upper limit established by the agreement – for plants and animals, and two-thirds of the risk for insects. Species in Europe, Southern Africa, Australia and the Amazon would benefit the most.
Previous research focused on measuring the benefits of containing warming to 3.6 degrees Fahrenheit. Those studies did not analyze how insects would be affected.
Minimizing the impact of climate change on insects is particularly important, the authors note, as they are critical for “ecosystem services,” such as pollinating flowers and crops and as part of the food chain for animals.
The team studied roughly 115,000 species including 71,000 plants, 31,000 insects, 1,700 mammals, 8,000 birds, 1,700 mammals, 1,800 reptiles and 1,000 amphibians.
“We wanted to see how different projected climate futures caused areas to become climatically unsuitable for the species living there,” said lead author Rachel Warren, a researcher with the Tyndall Center for Climate Change Research at the University of East Anglia in the United Kingdom.
“We measured the risks to biodiversity by counting the number of species projected to lose more than half their geographic range due to climate change.”
The authors found that achieving the primary objective of the Paris agreement – limiting warming to 2.7 degrees Fahrenheit – would produce significant benefits for biodiversity.
“Insects are particularly sensitive to climate change. At 2 degrees Celsius (3.6 degrees Fahrenheit) warming, 18 percent of the 31,000 insects we studied are projected to lose more than half their range, Warren said. “This is reduced to 6 percent at 1.5 degrees Celsius (2.7 degrees Fahrenheit). But even at 1.5 degrees Celsius, some species lose larger proportions of their range.”
Even if nations meet their international pledges to curb carbon dioxide emissions, global warming is projected to reach roughly 5.4 degrees Fahrenheit by 2100. This would cause nearly 50 percent of insects to lose half their range.
“This is really important because insects are vital to ecosystems and for humans,” Warren said. “They pollinate crops and flowers, they provide food for higher-level organisms, they break down detritus, they maintain a balance in ecosystems by eating the leaves of plants, and they help recycle nutrients in the soil.
“We found that the three major groups of insects responsible for pollination are particularly sensitive to warming.”
Warren added that if global warming reaches 5.4 degrees Fahrenheit, the ecosystem services insects provide would be greatly reduced. Previous research has shown that insects are already declining due to other factors, and the team’s report demonstrates that climate change would exacerbate these threats.
The study considers the ability of species to move to more suitable locations as the planet warms. Mammals, birds and butterflies have the greatest ability to relocate, which could allow some species to expand their range by 2100.
“If warming is limited to 1.5 degrees Celsius by 2100 then more species can keep up or even gain in range, whereas if warming reached 2 degrees Celsius by 2100 many species cannot keep up and far more species lose large parts of their range,” Warren said.
Co-author Jeff Price noted that some species would particularly benefit from keeping warming to no more than 2.7 degrees Fahrenheit. These include the critically endangered black rhinoceros, which is already threatened by habitat loss and poaching.
“There are also species which have been important in evolutionary theory and studied since the time of Charles Darwin, which would benefit from limiting warming to 1.5 degrees Celsius,” he said. “These include Darwin’s finches of the Galapagos, such as the large ground finch.”