US researchers found major changes in plant distribution caused by warming on Earth 55 million years ago.

Plant fossils from the Bighorn Basin in Wyoming, the United States, showed warmth-loving plants moving northward to replace the original vegetation when the planet warmed up over about 10,000 years during a period called the Paleocene-Eocene Thermal Maximum.

The warming raised the average temperature by between 9 and 18 degrees Fahrenheit, and the warmth lasted for 80,000 to 120,000 years.

A research team led by Scott L. Wing, chairman of the Department of Paleobiology at the Smithsonian's National Museum of Natural History, reported the findings in Friday's issue of the journal Science.

Researchers found at the same sites plant fossils including northern plants related to dawn redwood, alder, sycamore and walnut before and after the warm period.

It was reported that the warming was a result of an influx of carbon into the atmosphere.

Source: Xinhua