When it comes to the climate, Peter Betts is one of the most important people you’ve probably never heard of. If the world does manage to avoid the worst ravages of global heating, it will be thanks in part to the countless late nights he spent in windowless rooms, arguing over the placement of commas in impenetrable legal text.

Betts would probably have disagreed. He disliked ostentation and grand statements, preferring to get on unfussily with his job – for years, he was the UK’s main negotiator on climate, and leader of the EU’s team on the 2015 Paris agreement.

Legions of green campaigners would also baulk. Thirty-odd years of climate talks, with global “conference of the party” (Cop) summits almost yearly since 1992, and where are we? Greenhouse gas emissions are still rising, temperatures are breaking records – in the last two years the global average has for the first time exceeded the vitally important threshold of 1.5C above preindustrial levels – and we are fast approaching what scientists warn could be points of no return. No wonder Greta Thunberg slammed the negotiations as “blah, blah, blah”.

Yet the effort to craft lasting global agreement on the climate, with a view to binding governments to action that they would prefer to put off, has not been in vain. Before the Paris agreement, projections showed global temperatures heading towards 5C above preindustrial levels before the end of the century – at which point life on Earth would be unrecognisable. Today, if – and it’s a big if – all of the commitments made under Paris are fulfilled, the world will reach 2.7C of heating – still way over the limit of safety, but enough to keep hope alive.

All of this is the subject of Betts’s book, The Climate Diplomat, published nearly two years after his death. Told in his straightforward, no-frills style, but with plenty of sardonic asides and cheeky anecdotes, this account of more than a decade of climate talks is accessible to general readers but has enough previously unknown detail to satisfy the Cop nerd.

Typically self-effacing, Betts dismisses his own background – born “at the bottom of the heap” in 1959, he grew up in a small flat with an outside toilet in Battersea, south-west London, went to Oxford then struggled to find a vocation before joining the civil service as “the fast streamer from the gutter”, according to a patronising colleague – in just a couple of paragraphs. I’d have liked a little more, but he moves briskly through his first decades as a civil servant in London and Brussels to his analysis of global attempts to tackle the climate crisis, cutting through some of the misperceptions of both left and rightwing activists, and giving his prescriptions for what might work in future. Correctly, he points out that some on the left want the climate to be part of a slate of progressive positions, such as the call for reparations, which alienates some and plays into the hands of those who would wage culture war. “Hearing some leftwing commentators,” he warns, “it is not always clear that their real priority is tackling climate change. Of course we must confront the past, including colonialism, but we will not settle all the issues concerned to everybody’s satisfaction quickly. Sadly, our climate is changing too rapidly for that.”

Betts is a fine guide to the strangely addictive nature of Cops, which for all their frustrations have a kind of majesty, as one of the few remaining forums in which the world gets together to discuss our collective future, and where the poorest nations are afforded the same rights as the richest. It is the only place where those suffering the worst impacts of climate breakdown can meet across the table with the countries – looking at you, Saudi Arabia – trying to obstruct their rescue. (Readers who can’t get enough of the intricacies of the Cop process might want to turn, after this, to the cerebral former US envoy Todd Stern’s meticulous recent tome, Landing the Paris Climate Agreement.)

Betts and Stern come at this from relatively similar developed country positions, which will frustrate many readers who want more of the global south perspective. Equally fascinating, but sadly about as likely as a windmill on the White House, would be an honest viewpoint from one of the autocracies that holds the key to the crisis.

Betts can be scathing about the mistakes of government, and unsparing of the stupidities of the Cop process. At several points, Betts points out how the last Conservative government fomented an increasingly fractious attitude towards civil servants. He says Claire Perry O’Neill, who played a major role in ensuring Cop26 was hosted by the UK, was “the first minister I had really struggled with”.

It is fashionable in populist circles – think of Elon Musk’s Department of Government Efficiency, or the chainsaw-wielding president Javier Milei of Argentina – to dismiss and dismantle the work of civil servants. But when institutions are pushed aside, the powerful forces of big money step in. There are always other grey suits waiting to fill the place of bureaucrats, and the difference is they’re not working for you.

World leaders will gather again this autumn to try to put us on track to meet the Paris goals, despite Donald Trump’s campaign against it. Betts, of course, will not be there, having succumbed to a brain tumour in October 2023. His book, largely written during his final illness, and finished with the assistance of his partner Fiona MacGregor, unsentimentally and briefly recounts his treatment.

Part memoir and part penetrating analysis, with lessons for the future as well as revelations from the past, in some of its best passages this book reads like a briskly paced thriller. Except – depressingly – we all know whodunnit.