Here’s why Donald Trump tweets about “global warming,” not “climate change.”

The president’s first public statement about climate change since taking office came—how else—in the form of a tweet on Thursday evening. With a potentially record-breaking cold snap headed for the northeastern United States this weekend, he repeated a joke he’s been making for years:

This tweet doesn’t shed any new light on Trump’s views on climate change, which he has said is a “hoax” (for the record, it’s not, and there’s a big difference between climate and weather). But there is something to be gleaned from Trump’s use of the term “global warming” instead of “climate change,” because it shows how Trump and other climate deniers manipulate scientific terminology for ideological purposes.

Trump constantly uses the phrase “global warming” instead of “climate change.” On Twitter, he’s used the former 106 times, and the latter only 36 times. But there’s a fundamental difference between the two: Global warming refers to the overall, average increase in atmospheric temperature and sea surface temperatures across the world, which is happening because of heat-trapping gases emitted by humans. Climate change refers to the many other weird things happening because of the increase in greenhouse gases. Climate change includes global warming; global warming is just one part of climate change.

Climate-change deniers have, over the years, accused scientists of changing the term—from global warming to climate change—because people were starting to catch on that it still gets extremely cold sometimes. That’s not true, as Trump’s own NASA explains: Climate scientists have used both terms to describe different things since at least 1975. But the idea that scientists somehow changed the terminology appears to have caught on; some even think it was changed to make sure deniers like Trump don’t make dumb jokes about the cold.

But that’s not the case either. Deniers like Trump started lying about how scientists use terminology in order to perpetuate the myth that scientists are lying to the public. And Trump only uses “global warming” because he can’t make the “ha ha it’s cold” joke if he uses “climate change,” which is the more encompassing and more correct term for the phenomenon ravaging the country. But that’s not to say that deniers, including those in the White House, haven’t found a way to manipulate that term, too.