BALBOA, Panama, Nov. 11 (UPI) -- An abrupt global warming episode 56 million years ago led to an explosion of plant diversity in northern South America, Panamanian researchers say.
A 9-degree Fahrenheit spike in temperatures during 10,000 years -- a blink of an eye on a geological scale -- had researchers expecting to find evidence of a mass die-off of many tropical plant species, ScienceNews.org reported.
"We were expecting to find rapid extinction, a total change in the forest," says study leader Carlos Jaramillo, a biologist at the Smithsonian Tropical Research Institute in Balboa, Panama. "What we found was just the opposite -- a very fast addition of many new species, and a huge spike in the diversity of tropical plants."
The study has resonance for today in raising new questions about how tropical rain forests might respond to global warming as atmospheric carbon dioxide levels rise because of fossil fuel burning and other industrial activities, researchers say.
Researchers say the warming, which took place at the boundary between the Paleocene and Eocene epochs of geologic time, is the closest analog they have to the global warming they expect in the future.
But unlike that warming's 5-degree increase over 10,000 years, researchers say they expect a 2-degree increase over just the next century, with more to come after that.
In the ancient warming event, the South American plants apparently dealt with the heat by diversifying in a great evolutionary burst.
"This shows that plants have the genetic variability already built in to cope with high temperatures and high CO2," Jaramillo says.
But that doesn't mean tropical forests will necessarily thrive under future climate change, he warns.
"It's not just a matter of applying what we learned at that time, because today the forest is very fragmented," Jaramillo says. "For the forests, I don't think global warming is going to be good."
