Global warming has propelled Earth's climate from one of its coldest decades since the last ice age to one of its hottest -- in just one century.
A heat spike like this has never happened before, at least not in the last 11,300 years, said climatologist Shaun Marcott, who worked on a new study on global temperatures going back that far.
"If any period in time had a sustained temperature change similar to what we have today, we would have certainly seen that in our record," he said. It is a good indicator of just how fast man-made climate change has progressed.
A century is a very short period of time for such a spike.
It's supposed to be cold
The Earth was very cold at the turn of the 20th century. The decade from 1900 to 1909 was colder than 95 percent of the last 11,300 years, the study found.
Fast forward to the turn of the 21st century, and the opposite occurs. Between 2000 and 2009, it was hotter than about 75 percent of the last 11,300 years.
If not for man-made influences, the Earth would be in a very cold phase right now and getting even colder, according the joint study by Oregon State University and Harvard University. Marcott was the lead author of the report on its results.
To boot, the range of temperatures from cold to hot produced since the industrial revolution began are about the same as the 11,000 years before it, said Candace Major from the National Science Foundation, "but this change has happened a lot more quickly."
Far from natural warming