More than a quarter of nearly 1,000 cactus species could lose over 80% of their climatically suitable habitat by 2100, a new Nature study warns.
Climate models that account for severe droughts predict substantially greater habitat losses than those based on average climate conditions.
Including extreme droughts increased the proportion of species projected to lose more than 80% of suitable habitat from 1–15% to 25–35% across different emissions scenarios.
Cactus diversity hotspots in Chile, Peru and northeastern Brazil face particularly severe risks, potentially threatening ecosystems that depend on these plants.
Researchers warn that even drought-adapted species may struggle to survive longer, more intense droughts and call for climate extremes to be included in biodiversity risk assessments.
Even cacti, among the world's most drought-tolerant plants, face severe threats from climate change, with conventional climate models potentially underestimating the risks by failing to account for extreme weather events, a new study has found.
The study, published in Nature on November 11, 2026, found that including severe droughts in climate projections substantially increased the estimated loss of suitable habitat for nearly 1,000 cactus species across the Americas.
Led by Michiel Pillet of the University of Arizona, the research examined 993 species of the Cactaceae family, using 648,316 occurrence records alongside species distribution models and new spatial data on severe droughts, including the combined effects of rising temperatures.
The researchers found that models incorporating severe droughts performed better than those based on average climate conditions in 91 per cent of cases.
Across different emissions scenarios, and assuming species could disperse up to 100 km, incorporating severe droughts increased the proportion of cactus species projected to lose suitable climatic habitat from 58-61 per cent to 69-72 per cent.
The share of species projected to lose more than a quarter of their suitable habitat rose from 26-43 per cent to 55-58 per cent.
More significantly, the proportion facing losses of over 80 per cent increased from 1-15 per cent to 25-35 per cent when severe droughts were included.
When the models assumed that species could not disperse to new areas, the proportion projected to lose suitable habitat increased further, to 84-85 per cent.
Cactus diversity hotspots in Chile, Peru and northeastern Brazil could be particularly vulnerable, with some regions projected to lose more than a quarter of their current cactus species richness.
Cacti play important ecological roles, providing food and shelter for numerous animal species. Their decline could therefore affect wider ecosystems and the wildlife that depends on them.
The findings also raise concerns about existing assessments of extinction risk.
The 2015 Global Cactus Assessment found that 31 per cent of cactus species were threatened with extinction. Since then, researchers have identified additional species, revised classifications and documented growing threats from illegal collection and climate change.
"Our findings indicate that the adaptations of cacti to drought may not be sufficient in a future with longer and more intense droughts," Pillet said.
He added that the results could apply to other plant groups and called for extreme weather events to be incorporated into assessments for the International Union for Conservation of Nature's (IUCN) Red List of Threatened Species.
The researchers concluded that accounting for climatic extremes is essential to improving forecasts of biodiversity loss and developing effective conservation strategies across species and ecosystems.