In the years before moving to the White House, Donald Trump used Twitter to call climate change "nonsense" peddled by "con artists" and "created by and for the Chinese."

Whenever temperatures reached teeth-chattering lows during New York winters, he would tweet, tongue in cheek, that what we needed was a "heavy dose of global warming."

President Donald Trump speaks at Palm Beach on December 27. Credit:Evan Vucci

But since becoming president, Trump laid off the broadsides - at least on Twitter - against the broad scientific consensus that the burning of fossil fuels and other human activity is indeed warming the planet.

On Thursday, he broke his silence.