Visitors to the Santa Catalina Mountains just outside Tucson, Arizona encounter a very disturbing sight: patches of dead alligator junipers scattered across hillsides at the base of the range. Wildfires did not destroy these trees — climate change did.
The trees can’t survive where it’s hot, so many have moved to higher elevations, where it is cooler. But if the heat keeps rising, they will die there too, and eventually cease to exist entirely.
“They can’t cope with the conditions,” says John J. Wiens, professor of ecology and evolutionary biology at the University of Arizona. “They simply can’t change fast enough.”