Sen. James Inhofe (R-Okla.) brought a real snowball onto the Senate floor to discusses climate change. (C-SPAN)

SEN. JIM Inhofe (R-Okla.) chairs the Environment and Public Works Committee — and he seems determined to make that fact a national embarrassment.

Mr. Inhofe delivered a Senate floor speech about the “hysteria on global warming” last week with two conspicuous props. One was a blown-up photo of his family standing in front of an igloo labeled “AL GORE’S NEW HOME.” The Inhofe clan constructed it following a 2010 “snowstorm that had been unprecedented, it set a record that year,” Mr. Inhofe explained.

“In case we had forgotten, because we keep hearing that 2014 has been the warmest year on record,” Mr. Inhofe continued, reaching for a plastic bag next to his lectern, “I ask the chair, do you know what this is? It’s a snowball, just from outside here. It’s very, very cold out.”

Mr. Inhofe then tossed his snowball at the presiding officer.

The senator was right about one thing. The weather in Washington has been unusually cold. This February might turn out to be the capital’s coldest in 36 years. However, one could just as easily point out that, despite some bitter temperatures on the East Coast, the Northern Hemisphere is set to break the record for the least amount of cold air ever.

All of this is really beside the point: Global warming is a long-term and worldwide trend. The fact that it’s cold at one place on the Earth at one point in time does not undermine the contention that industrial greenhouse-gas emissions are warming the planet over the course of decades.

There is no reasonable doubt that the world is heating up. This conclusion is based on direct observation of multiple lines of evidence, from temperature readings to tree-ring measurements. Temperatures bump up and down month to month, year to year. But the long-term trend is up. The 2000s was the warmest decade on record, followed by the 1990s, followed by the 1980s.

“If the land surface records were systematically flawed and the globe had not really warmed, then it would be almost impossible to explain the concurrent changes in this wide range of indicators produced by many independent groups,” the National Oceanic and Atmospheric Administration concluded when it announced that the 2000s had set a decadal temperature record. “The warming of the climate system is unequivocal.”

Neither science nor evidence trouble Mr. Inhofe’s benighted complacency. “The hoax is that there are some people who are so arrogant to think that they are so powerful, they can change climate,” he said in January. “Man can’t change climate.”

There is polling data suggesting some Americans’ views on climate change vary with the weather. Politicians worthy of Americans’ trust dispel this sort of ascientific thinking — they don’t encourage it. The Republican Party should be mortified by the face of their environmental leadership.