A new study finds nearly one-third of the planet’s species could face extinction by the end of the century if humans don’t reduce greenhouse gas emissions. This risk increases as global warming intensifies. A team led by Mark Urban, a biologist and ecologist at the University of Connecticut, warns that if global temperatures rise more than 1.5 °C above pre-industrial averages—exceeding the target set by the Paris Agreement—the extinction of species will accelerate rapidly. This is particularly true for amphibians, as well as species in mountainous, island, and freshwater ecosystems, and those found in South America, Australia, and New Zealand.
The climate crisis is shifting temperatures and changing precipitation patterns, which directly affect the survival of many species. For instance, rising temperatures have disrupted monarch butterflies’ migration, causing them to arrive before the plants they pollinate have bloomed. Many animals and plants are moving to different latitudes or higher altitudes in search of more favorable conditions. But numerous species cannot adapt to these new environments, leading to population declines and, in some cases, extinction.
What did the study find? Mark Urban’s team analyzed more than 30 years of research on biodiversity and climate change, covering over 450 studies across a wide range of species. The findings are concerning. If greenhouse gas emissions are limited in line with the Paris Agreement, roughly 180,000 species—about one in fifty worldwide—will be at risk of extinction by 2100. If temperatures rise by 2.7 °C, one in twenty species could disappear. Warming beyond that would dramatically increase the number of species facing extinction: a rise of more than 4.3 °C could affect 14.9 percent of species, and an increase above 5.4 °C could threaten as much as 29.7 percent of Earth’s biodiversity.
Mark Urban told Live Science that the number of species at risk will jump once warming passes 1.5 °C. If global warming remains below that threshold, consistent with the Paris Agreement, the overall extinction risk will not climb significantly. Amphibians are especially vulnerable because their life cycles depend on weather and they are highly sensitive to drought and changes in precipitation. Species in mountainous, island, and freshwater ecosystems are also at high risk because the isolation of those environments makes migration and finding suitable climates difficult.
Limiting greenhouse gas emissions would slow warming and help prevent extinctions worldwide. Identifying which ecosystems are most affected by climate change will help target conservation efforts where they are needed most. The results of this research were published in the journal Science.
