Donald Trump. REUTERS/Lucas Jackson Republican presidential front-runner Donald Trump said Monday morning that Sen. Bernie Sanders (I-Vermont) had misfired an attack against him at the Democratic debate the night before.

During the debate, Sanders said he couldn't imagine electing a president who believed that climate change is "a hoax invented by the Chinese." Sanders specifically cited Trump to make his point.

That was an apparent reference to a 2012 tweet by Trump, in which the real-estate mogul wrote, "The concept of global warming was created by and for the Chinese in order to make US manufacturing non-competitive."

Trump was asked about Sanders' attack the next day during a "Fox & Friends" interview. He said his accusation against the Chinese was an obvious joke.

"I think that climate change is just a very, very expensive form of tax. A lot of people are making a lot of money. I know much about climate change," Trump said. "I've received many environmental awards. And I often joke that this is done for the benefit of China — obviously I joke — but this done for the benefit of China."

He added: "Because China does not do anything to help climate change. They burn everything you can burn. They couldn't care less. Their standards are nothing. But in the meantime, they can undercut us on price. So it's very hard on our business."

Trump has for years used words like "hoax," "canard," "mythical," "con job," "nonexistent," and "bulls---" to reject mainstream climate science: