If Left Unchecked, Climate Type Will Change Across Nearly Half the World by 2100

If climate change continues at the projected pace and the world becomes more than 3 degrees Celsius warmer by the end of the century, the spread of plant species in nearly half of the world could be affected, according to new research published in Global and Planetary Change.

"Climates are associated with certain types of vegetation. If the surface continues to get warmer, certain native species may no longer grow well in their climate, especially in higher latitudes. They will give their territory to other species. That is the most likely scenario," said study leader Song Feng, an atmospheric scientist at the University of Arkansas.

Feng and his colleagues used what's referred to as the "business as usual" model for their climate simulations. That model assumes there will no significant reduction in the greenhouse gas emissions that are warming the planet.

The researchers examined shifts in climate regimes around the world using the Köppen-Trewartha climate classification, which is based on the concept that native vegetation is the best expression of climate, according to a statement from the University of Arkansas.

Feng predicts that climate types will change in 46.3 percent of the global land area by 2100. One of the ways this will materialize is by tundra in Alaska and Canada giving way to trees, shrubs and plants typical of more southerly climates.

For the study, Feng and his colleagues analyzed climate observations made from 1900-2010 and climate simulations that spanned from 1900-2100.The data was taken from World Climate Research Programme.

"Changes in precipitation played a slightly more important role in causing shifts of climate type during the 20th century. However, the projected warming plays an increasingly important role and dominates shifts in climate type when the warming becomes more pronounced in the 21st century," Feng said. "Those vast changes also imply that the global land area is experiencing vegetation-type conversions, with species distributions quite different from those that are familiar to us in modern civilization," he said.

On a broad scale, the models consistently project increasing precipitation over high latitudes in the Northern Hemisphere and reduced precipitation in all of Australia, the Mediterranean, southwestern North America and southern Africa.

"This study is on the broad scale," Feng said. "It's showing the big picture."