At a Glance

Researchers studied how vegetation changed after the ice age 21,000 years ago to project howecosystems may change with global warming.One significant difference between warming after the ice age and what is occurring today is the speed at which temperatures are increasing.

Some 21,000 years ago, vegetation was significantly altered as the planet warmed afterthe last ice age, andclimate change is expected todramatically alter vegetation in the next 100 to 150 years,leaving no ecosystem on Earth safe, a new study says.

Researchers in astudy published this week in the journal Science used reports from 594 sites to analyzehow after the last ice age to project howecosystems may change as temperatures continue to rise.

"We found that experienced big changes," Connor Nolan, a doctoral candidate in theUniversity of Arizona's department of geosciences, said in a press release. "About 70 percent of those sites experienced large changes in the species that were there and what the vegetation looked like."

Touted as the most comprehensive compilation to date of vegetation and other ecological data covering the period from the height of the ice ages 21,000 years ago to the pre-industrial era, the research conducted by 42 international scientists paints a dire portrait of what Earth may look like in the years to come if we don't reduce greenhouse gases.

Jonathan Overpeck, aco-author of the study and dean of the School for Environment and Sustainability at the University of Michigan, said the changes from global warming would impact biodiversity and "derail vital services that nature provides to humanity, such as water security, carbon storage and recreation."

"If we allow climate change to go unchecked, the vegetation of this planet is going to look completely different than it does today, and that means a huge risk to the diversity of the planet," Overpeck said.

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As Earth warmed after the last ice age, areas of the world that experienced the greatest increase in temperatures saw the greatest changes to vegetation. This is expected to similar although on a much larger scaleas climate change warms the planet in the next decades.

"We used the results from the past to look at the risk of future ecosystem change," Nolan said. "We find that as temperatures rise there are bigger and bigger risks for more ecosystem change."

The authors of the study noted that one significant difference between warming after the ice age and what is occurring today is the speed at which temperatures are increasing and how quickly vegetationand ecosystemsare changing.

"We’re talking about the same amount of change in 10 to 20 thousand years that’s going to be crammed into a century or two," said co-author Stephen Jackson, director of theU.S. Geological Survey’s Southwest Climate Adaptation Science Center. "Ecosystems are going to be scrambling to catch up."

As an example of what may happen in the future unless greenhouse gases are reduced, Jackson noted thatvegetation that will return after deadly wildfires in the West this summer may not be the same species that were there before the blazes.

"You take the ponderosa pine forests in the Sky Islands (Arizona) and turn it into oak scrub — we’re starting to see that," Jackson said.