"PRESIDENT Trump is pulling out of the Paris climate change agreement. How will the panellists deal with that?” Coming in the closing stages of the election campaign’s final UK-wide televised leaders’ debate on Wednesday evening, this question was followed by the presenter asking for it to be answered “briefly”.

To be positive for a moment, it was a rare example of climate change getting any kind of attention in these election debates. Despite general agreement that it represents one of the most profound challenges for our society, our economy and indeed for the future of our civilisation, it’s very seldom treated as the political issue it is. Indeed during Trump’s own election campaign, I don’t recall any serious scrutiny of his delusional theory that climate change is a conspiracy invented by the Chinese.

Of course, Trump’s rhetoric is such a continuous stream of inane bombast that it can be hard to focus in on any single specific claim; but of course that’s the point, and it’s how he gets away with it day after day.

Last night, however, he confirmed that he is taking the US out of the Paris Agreement. He said moves  will begin to negotiate a new deal that he said would not “disadvantage” the US. His administration had been heavily trailing the fact that he intended to withdraw, and in some ways, his position won’t alter much.

We know that, in terms of domestic policy, his administration is relentlessly hostile to environmental concerns, and to the scientists who inform us about those concerns. But we also know that there is some climate leadership in the US; it’s coming from state and city governments which see both the urgency of the problem and the opportunities that acting quickly can create.

There are voices in the private sector also calling for government action, however they tend to be the businesses with the least to lose. The big polluters in the fossil fuel industry and its biggest customers are still happily throwing money at any politician willing to deny reality.

In addition, both China and the EU are now committed to the Paris Agreement regardless of the US stance, and this is likely to be the position of most countries. It may take time (and perhaps a different president) for the US to rejoin the rational world, but that should not stop most of the planet’s governments from taking action.

When the UK leaves the EU (and regardless of whether the UK itself holds together in the years that follow) it will be essential that it maintains climate cooperation with our European neighbours.

Of course, Paris itself is little more than a statement of intent, and we’re yet to see a widespread acceptance of the course of action which will be needed to make it a reality.

In the short debate which followed the climate question on Wednesday night, only one person made clear the scale of the challenge. Caroline Lucas, co-leader of the Green Party of England and Wales, was the sole political leader who was willing to say what others avoid – that the bulk of our fossil fuels must remain in the ground, unburned.

The world has vastly more than we can afford to use, yet our economies continue to lock in high patterns of energy use, remain overinvested in the “carbon bubble”, and regard production of oil, gas and coal as having positive value instead of accepting that  it’s a source of deep vulnerability.

Sadly, Scotland is little different. The Scottish Greens have developed proposals showing that, with the right investment, far more jobs can be created in new sustainable industries than will be lost in oil and gas. More to the point, those unsustainable jobs are being lost already, and nothing will keep the fossil fuel industry running forever. Its end is coming fast, whether or not we choose to invest in an alternative.

Yet every other party still calls for ever bigger subsidies and tax breaks to keep extracting the stuff, and to go looking for more. And every other party continues the delusion that oil-hungry industries such as aviation can keep growing forever.

Indeed, I can’t for a moment see why residents in constituencies such as Glasgow North,where I live and am standing for election, should be sending MPs to Westminster to advocate for an extra runway at Heathrow, while public transport here remains unreliable and overpriced. Such business-as-usual actions will make our climate ambition utterly worthless, and would amount to something even worse than Trump’s delusional thinking – a conscious and fully informed refusal to act despite knowing the facts.

That’s why I’m standing with Caroline, and why  we need more  Green voices at Westminster.