Climate change threatens tens of thousands of plant species, according to two studies published in Science—one projecting how plant extinctions may unfold and another documenting how many flowering species already face a high risk of disappearing.
The future-looking work, led by University of California Davis ecologist Xiaoli Dong, focuses on how warming temperatures and shifts in rainfall and snowfall patterns can strip plants of the particular conditions they require to survive. The study projects that between 7% and 16% of the world’s plant species could lose at least 90% of their habitat and become “essentially extinct” in about 55 to 75 years.
Dong said the key driver is not only whether species can move, but how quickly habitats themselves become unlivable. “The warming rate drives the extinction,” Dong said. She added that the projected extinctions do not hinge on plants failing to relocate fast enough, telling reporters: “It is not because they are not moving fast enough.”
According to the study, habitat loss under climate change undercuts the usual expectation that plants could gradually shift into cooler regions. Dong and her colleagues used computer models to examine detailed potential futures for 18% of the world’s plant species, incorporating biology and climate simulations to estimate what happens as environments change.
The researchers also pointed to regions where the risk appears especially severe, including the Arctic, the Mediterranean and Australia. In the Arctic, Dong said warming is occurring faster than elsewhere, while in Australia the study found the threat is driven more by changes in rainfall rather than temperature alone.
The second paper, also published Thursday in Science, turns to present-day extinction risk for flowering plants. Researchers at Kew Gardens in the United Kingdom found that nearly 10,000 flowering plant species are currently in danger of blinking out, and they said the loss of those evolutionarily old, unusual species would remove 21% of Earth’s “tree of life.”
Felix Forest, an evolutionary plant biologist and lead author of the Kew study, said the work uses a 20-year system developed by British biologists to prioritize species conservation by saving species that are most unique. Forest described the goal as assessing what would be lost in terms of biological history and distinctiveness, rather than diagnosing what currently causes the extinction risk.
Forest said the conservation prioritization analysis found more evolutionary history at risk among unusual flowering plants than among almost any other group of flora and fauna, “except turtles and tortoises.” He also contrasted flowering plants with other animals, noting that some groups have close relatives that can share evolutionary history if a single species disappears, while flowering plants can include lineages such as the ginkgo that have no similar species.
Both studies argue that plant extinctions have often been overlooked compared with animals. Forest said humans tend to focus on “fluffy furry things and things with two wings,” and he framed that attention gap as part of why plant declines have not received comparable urgency.
Writing in a review of both Science studies, Chilean biologists Rosa Scherson and Federico Luebert said the world cannot wait to act to save endangered plant species and warned that when current conditions that support life become unstable, it can affect human food security and access to basic materials. “Maintaining the current conditions that support human life requires urgent action,” Scherson and Luebert wrote.