Stats in from a new paper show that between 2006 and 2011 between 4 percent and 13 percent of the earth's surface has been covered by extreme heat in the summer. That number, a big jump from the less than 1 percent of pre-1980, tells the scientists who wrote the paper that global warming is most certainly at work in major events like last year's heat wave in Texas, according to The New York Times' Justin GillisBut other scientists aren't so sure.  

The paper, which was published in the Proceedings of the National Academy of Sciences, was produced in part by James Hansen, a climate scientist, who is not free from controversy. The people who don't believe in climate change charge Hansen with tampering with the temperature record — although, Gillis notes, "there is no proof that he has done so and the warming trend has repeatedly been confirmed by other researchers" — but even his fellow scientists are uncomfortable with his role as a political activist. As Gillis writes about Hansen's recent work:

The findings led his team to assert that the big heat waves and droughts of recent years were a direct consequence of climate change. The authors did not offer formal proof of the sort favored by many climate scientists, instead presenting what amounted to a circumstantial case that the background warming was the only plausible cause of those individual heat extremes.

Dr. Hansen said the heat wave and drought afflicting the country this year were also a likely consequence of climate change.

Some scientists support the claim. Others, not so much: one thought there wasn't "persuasive evidence" backing up the claim that there was a link between heat waves and climate change, according to The Times. Another thought Hansen had was "exaggerating" the connection between specific events and the larger issue at hand. 

Image by Tony Campbell via Shutterstock