The G19 has sealed it, Trump really has strengthened the Paris Agreement

It was easy to be sceptical about the argument that the US withdrawal from the Paris Agreement would only serve to strengthen the green economy. After all, if the international accord was a huge step forward in tackling the existential risk presented by climate change, how could the exit of the world's largest and most powerful economy be anything other than a blow to its credibility?

But yesterday the argument put forward by former UN climate chief Christiana Figueres and others - that President Trump had done the world a favour by reinforcing the commitment to climate action amongst his fellow world leaders and many domestic critics - had its first engagement with geopolitical reality. It passed with flying colours. Faced with a US diplomatic offensive (emphasis on the offensive), the rest of the G20 held firm and unequivocally declared the Paris Agreement was "irreversible".

With a level of diplomatic sophistication that would shame a high school Model UN, the White House's naïve and flawed approach since Trump's logic-free Rose Garden explanation of his plan to quit the Paris Agreement really has served to strengthen the treaty and embolden global efforts to curb greenhouse gas emissions.

Make no mistake, the US wanted a deal on climate change in Hamburg. Trump and his team have repeatedly asserted their desire to renegotiate the Paris Agreement. They might not care much for scientific reality, but that can't help but be aware of political reality. This most sensitive of Presidents will have seen how his already subterranean approval ratings took yet another dent in the wake of his decision to exit the Paris deal. As a self-styled dealmaker-in-chief, he wanted a face-saving deal to be done that was compatible with his belief that the Paris Agreement was a bad deal for the US.

You can see this thinking at play in the section of the communique on energy and climate and the controversial paragraph the rest of the G20 refused to sign up to.

The US agreed to the group's overarching assertion that "a strong economy and a healthy planet are mutually reinforcing", and recognised the "opportunities for innovation, sustainable growth, competitiveness, and job creation of increased investment into sustainable energy sources and clean energy technologies and infrastructure". It also seemed to have no problem with the section reasserting the G20's commitment to the UN Sustainable Development Goals, which, lest we forget, including their own strong commitments on climate change.

Attempts at conciliatory language even extended into the critical paragraph Trump alone endorsed, stressing that US work with other countries to help them "access and use fossil fuels" would only apply to assisting them to use such fuels "more cleanly and efficiently". It also said this would be accompanied by attempts to help countries "deploy renewable and other clean energy sources". This 'all-of the-above' strategy was justified by the "importance of energy access and security in their nationally determined contributions", the paragraph concluded.

Just a few short years ago the vague and contradictory nature of this commitment would almost certainly have been enough to secure an agreement. After all, the argument that "clean and efficient" fossil fuels should be used in support of "energy access and security" has been deployed for years by many of the world's development banks. It is a manoeuvre straight out of the play book of Exxon and Peabody Energy and it has worked repeatedly in the past. Those nations that style themselves as climate hawks could kid themselves the commitment to "clean" fossil fuels covers only CCS and a short period of increased gas use, and Trump and co could return to Coal Country trumpeting a victory. Everyone would have left happy, with the exception of the poor states that will bear the brunt of climate change, who weren't invited anyway.

Going in to the summit it was even possible to envisage how an American administration that had not become a walking warning label for narcissistic incompetence could have pulled off such an outcome. Trump could have reached out to those nations whose reliance on fossil fuel reserves has always made their commitment to the Paris Agreement feel a little soft - Russia, Saudi Arabia, Turkey, Australia, Indonesia, we're looking at you. And yet despite his love-in with Erdogan and his convivial tete a tete with Putin, Trump was unable to drive a wedge between the newly formed G19.

A compromise that would have seriously tested the G19's resolve by at least attempting to address its concerns over fossil fuel emissions was not even attempted. A proposal that more clearly defined 'clean' fossil fuels as incorporating CCS or set a deadline for the use of gas as a 'bridging fuel' would have actually added something to the international debate. It would have also been hard for Merkel and Macron to reject out of hand, and could still have been presented as a win for the US fossil fuel industry. But no such proposal came.

Instead, the US stuck to its auto-satirical commitment to "clean" fossil fuels and in so doing only served to send a message to businesses and investors everywhere that the rest of the world regards the Paris Agreement as "irreversible" and really does see "clean" fossil fuels as an oxymoron.

At the end of a week when one of the world's (Chinese-owned) auto giants said it was switching pretty much wholesale to electric vehicle technology and the French government declared the sale of internal combustion engines will be phased out by 2040, the G19 sent the clearest signal yet that the Paris Agreement really did herald the beginning of the end of the fossil fuel era.

Meanwhile, Macron's plans for a second major climate summit this winter to mark the second anniversary of the Paris Summit will only serve to create further momentum behind the global decarbonisation push as more governments come forward to strengthen their national climate action plans.

Of course, there is still plenty of room for things to go wrong. Trump's team might finally start to develop some basic diplomatic competence in pursuit of an effort to divide and rule the G19. UK environmentalists will be extremely wary that the promise of a "very, very" quick US-UK trade deal could become a pawn in this game, opening the UK up to products developed using the lowest possible environmental standards. As the commander in chief of the world's most powerful country Trump still has the potential to do immense environmental damage by opening up tar sands, offshore oil zones, and coal seams. Plenty of states are vowing to defy his pollutocratic tendencies, but others are willing to aid and abet the torching of environmental standards and the undermining of clean technologies.

But while these risks exist they are being imposed on a general direction of travel for the global business community that is now more firmly wedded than ever to the development of a zero carbon economy. The G19 yesterday made it absolutely clear which side of the debate it is on, and which signals it wants to send to investors and infrastructure developers.

Meanwhile, those climate sceptics and fossil fuel boosters who are today celebrating the US stance might be wise to ask themselves how it looks when the only world leader deploying your arguments and embracing your world view is mired in countless nepotism and corruption scandals. How sustainable is it really for your biggest cheerleader to be the least popular US president in history?

When the backlash against Republican climate scepticism eventually comes - and demographics and economic logic means it will - the US will be able to rejoin a Paris Agreement that has been turbocharged in the intervening years by both the plummeting cost of clean energy and political leadership of the G19.

It looks like Christiana Figueres was right, after all. Perhaps we should all start working on thank you letters to President Trump.