Back in 2012, some guy with too much time on his hands logged on to Twitter and sent out this viral bit of trolling:

The concept of global warming was created by and for the Chinese in order to make U.S. manufacturing non-competitive. — Donald J. Trump (@realDonaldTrump) November 6, 2012

People laughed. They mocked. They retweeted. But four years later, that guy is actually going to be president of the United States — with vast power over climate change policy. So today, China felt the need to clarify.

At the ongoing United Nations climate conference in Morocco, China’s vice foreign minister, Liu Zhenmin, told assembled reporters that, uh, nope, global warming isn’t a Chinese hoax. It couldn’t possibly be. Because it was the United States that started this whole idea of global cooperation on climate change in the first place.

“If you look at the history of climate change negotiations, actually it was initiated by the IPCC [Intergovernmental Panel on Climate Change] with the support of the Republicans during the Reagan and senior Bush administration during the late 1980s,” Liu told reporters, according to Bloomberg (which points out that this history is, in fact, correct).

The more serious backdrop here is that Trump is threatening to pull the United States out of the Paris climate deal, undermining the fragile progress that the world has been making over the past year on tackling global warming. China, for one, has been warning Trump not to do this — and putting itself in position to dominate the talks if the US leaves.

It’s also a remarkable shift, when you step back and think about it. Ten years ago, China was seen as the main obstacle to global climate talks. But in the years since, the country has made huge investments in clean energy, pushed to curtail its once insatiable appetite for coal (coal consumption has fallen for three years in a row in China), and taken a much more proactive role in helping lead international climate talks.

And now, apparently, debunking nonsense tweets from the next American president.