WASHINGTON – A prominent physicist and skeptic of global warming spent two years trying to find out if mainstream climate scientists were wrong. In the end, he determined they were right: Temperatures really are rising rapidly.

The study of the world’s surface temperatures by Richard Muller was partially bankrolled by a foundation connected to global warming deniers.

Spurred to action by “Climate-gate,” a British scandal involving hacked emails of scientists, Muller pursued long-held skeptic theories in analyzing the data.

Yet he found that the land is 1.6 degrees warmer than in the 1950s. Those numbers from Muller, who works at the University of California, Berkeley and Lawrence Berkeley National Lab, match those by the National Oceanic and Atmospheric Administration and NASA.

He said he went even further back, studying readings from Benjamin Franklin and Thomas Jefferson. His ultimate finding of a warming world, to be presented at a conference today, is no different from what mainstream climate scientists have been saying for decades.

What’s different, and why everyone from opinion columnists to “The Daily Show” is paying attention, is who is behind the study.

One-quarter of the $600,000 for the research came from the Charles Koch Foundation, whose founder is a major funder of skeptic groups and the tea party. The Koch brothers, Charles and David, run a privately held company involved in oil and other industries, producing sizable greenhouse gas emissions.

Muller’s research team carefully examined two chief criticisms by skeptics. One is that weather stations are unreliable; the other is that cities, which create heat islands, were skewing the temperature analysis.

“The skeptics raised valid points, and everybody should have been a skeptic two years ago,” Muller said in an interview. “And now we have confidence that the temperature rise that had previously been reported had been done without bias.”

Muller did not address in his research the cause of global warming. The overwhelming majority of climate scientists say it’s man-made from the burning of fossil fuels such as coal and oil. Nor did his study look at ocean warming, future warming and how much of a threat to mankind climate change might be.

Still, Muller said it makes sense to reduce the carbon dioxide created by fossil fuels.

“Greenhouse gases could have a disastrous impact on the world,” he said. Still, he contends that threat is not as proven as the Nobel Prize-winning Intergovernmental Panel on Climate Change says it is.

Today, he’s taking his results — four separate papers that are not yet published or peer-reviewed, but will be, he says — to a Santa Fe, N.M., conference expected to include both prominent skeptics and mainstream scientists.