The percentage of the earth’s land surface covered by extreme heat in the summer has soared in recent decades, from less than 1 percent in the years before 1980 to as much as 13 percent in recent years, according to a new scientific paper.

The change is so drastic, the paper says, that scientists can claim with near certainty that events like the Texas heat wave last year, the Russian heat wave of 2010 and the European heat wave of 2003 would not have happened without the planetary warming caused by the human release of greenhouse gases.

Those claims, which go beyond the established scientific consensus about the role of climate change in causing weather extremes, were advanced by James E. Hansen, a prominent NASA climate scientist, and two co-authors in a scientific paper published online on Monday in the Proceedings of the National Academy of Sciences.

“The main thing is just to look at the statistics and see that the change is too large to be natural,” Dr. Hansen said in an interview. The findings provoked an immediate split among his scientific colleagues, however.