Down with old King Coal: A protester holds a sign demanding to end coal burning during the 23rd Conference of the Parties (COP) climate talks in Bonn. Photo/AP
"Promoting coal at a climate summit is like promoting tobacco at a cancer summit," said Michael Bloomberg, the former New York mayor, but President Donald J Trump did exactly that.
He sent a team of American diplomats and energy executives to the annual world climate summit, being held this year in Bonn, Germany, to extol the wonders of "clean" coal. Bloomberg, now a United Nations special envoy for climate change, got it right - the audience at the US presentation heckled and mocked the presenters.
Where people who were concerned about global warming once worried about whether the US government would dare to defy the fossil fuel lobby at home, the denialists now control the government - and it turns out not to matter all that much.
There are several reasons for that. One is that global coal use has gone into steep decline as the cost of renewable energy has dropped. It's just not competitive any more, and China and India have cancelled plans for hundreds of new coal-fired power plants this year.
Even in the United States, the share of electricity coming from coal fell from 51 per cent in 2008 to only 31 per cent last year - and US coal companies are going bankrupt.
A second reason is that Trump's decision to pull the United States out of the 2015 Paris Climate Agreement has had zero impact internationally. The fear that other countries would also default on their commitments proved to be unfounded, and the US is the literally the only country on the planet that does not subscribe to the treaty.
Finally, Trump has been outflanked by a new alliance announced in Bonn on Tuesday that links the 15 US states committed to strong climate action with the Canadian and Mexican governments in a continent-wide group that concentrates on phasing out coal power and boosting clean power and transport. Much of the US contribution to emissions cuts that Trump reneged on will be covered by these state-level American initiatives. There are other causes for alarm, of course.
After three years when global carbon dioxide emissions stayed steady, albeit at a very high level, they have started rising again. And there is an unexplained rise in methane emissions in the tropics, not caused by burning fossil fuels, that leads some scientists to suspect that one of the dreaded feedbacks is kicking in.
Feedbacks are the spectre at the feast. You can get everything else right, your emissions are going down nicely, and you are on course to stop the warming just before the average global temperature reaches two degrees higher - and then suddenly, the whole global system goes into overdrive. The warming that human beings have already caused has triggered some other, natural source of warming that we cannot shut off.
So we are still living dangerously, and it is still uncertain whether we can ratchet down emissions targets fast enough to stop the temperature rise in time. But there are big changes in the offing that will make it easier to cut emissions - meat substitutes and lab-grown meat, electric vehicles and rapidly falling prices for renewables like solar and wind.
There is also now a unity of purpose that was previously absent from the climate talks: the long struggle between the rich and the poor countries over who is to blame for the problem and who pays for the damage is largely over. And although President Xi did not come in person, China is definitely taking the lead.
Nobody in Bonn is celebrating the US government's defection from the fight against climate change, but their panic is long past.
The Bonn meeting is concentrating on writing the rules for measuring how countries are complying with the promises they have made on emissions cuts. They also need to figure out how to organise the five-yearly reviews at which the countries are supposed to adopt progressively higher targets for cuts.
When the conference closes today, there will be no exciting new announcements of breakthroughs, but we don't need that. The real breakthrough came in Paris in 2015, and the objective now is to keep the show on the road. So far, so good.
■Gwynne Dyer is an independent journalist whose articles are published in 45 countries.