Jonathan Porritt described the COP30 climate talks as "a sustained exercise in suicidal fantasy" during his opening remarks at a book launch event at the Department of Engineering.
The campaigner and author of the newly-launched Love, Anger and Betrayal began with a blistering critique of the recently-concluded climate conference in Belem, Brazil, during the event on Thursday (27 November), which was introduced by Hugh Hunt, professor of engineering at the University of Cambridge and deputy director of the Cambridge-based Centre for Climate Repair.
Sir Jonathon, who is on a nine-city book tour, began by speaking of the challenges that climate breakdown is already bringing to millions of people around the world.
"The 10 million residents of a capital city will have to be moved, according to the nation's leader," he said. "Who said that? It was the president of Iran, who said the move - to a place not yet designated - comes amid a deepening ecological crisis and acute water shortage.
"There is a conflict between living in the real world and living in a total suicidal fantasy," he continued, "and alas the fantasy is winning."
The COP30 talks were a further manifestation of this resolute refusal to engage with the actuality of climate change, he added.
"COP30 was a sustained exercise in suicidal fantasy with very little understanding of the hard-edged realities of the climate crisis today.
"In only one COP from the last 30 years - COP28 in Dubai - were the words 'fossil fuels' even mentioned. The final communique there said 'we must now transition away from fossil fuels'."
The COP30 final communique controversially scrubbed all mention of a fossil fuel roadmap from the text of the final outcomes following fierce pushback from countries including Russia, Saudi Arabia and India, though UK Energy Secretary Ed Miliband described the talks in Brazil as a "step forward" because of financial commitments made to already-affected nations.
"The fantasy sticks in my mind," Sir Jonathon noted. "I do not understand how people can't see through this tissue, this obfuscation, of lies. How the representatives of countries can put their names to these suicidal fantasies can't be explained."
Love, Anger and Betrayal: Just Stop Oil's Young Climate Campaigners is co-authored with 26 young climate activists, including former University of Cambridge student Cressie Gethin and Cambridge resident Chiara Sarti.
In the book, the author suggests the world will only become forced to acknowledge the existential crisis humanity faces when the insurance markets collapse. At the Department of Engineering, he returned to this theme with a reminder that Günther Thallinger, a board member of the global insurance giant Allianz SE, stated that at a certain point of global warming - around 3°C - climate damage will become uninsurable.
"We're heading for 2.4 to 2.7 degrees of global warming [above pre-industrial levels] by the end of the century and that will only be delivered if all countries do what they say they're going to do," said the Green Party and Friends of the Earth advocate, who has also worked with governments and the corporate sector in his half-century of activism, which most recently included being arrested in London for holding a sign in support of the proscribed organisation Palestine Action.
"There is no way to adapt to temperatures beyond human tolerance," Thallinger went on. "So no mortgage, no investments, no financial stability, ever again because the financial sector ceases to function. Capitalism ceases to be functional. And what became of this warning shot? It was ignored. To call this an environmental crisis is inaccurate - it's an economic crisis, a human rights crisis and a crisis for the future of humanity. So it was very rewarding to work with 26 young people who understand this."
It is also a security crisis, he said, because the US Secretary of War, Pete Hegseth, has committed America to a $1trn military budget.
"Think of how much that $1trn would buy in terms of underpinning the security of people threatened by the climate crisis today. And many governments are comfortable with being in a near-permanent war, and that is being played out in the genocide in Gaza because half of that £1trn will go to four corporations in the US, who have all been closely involved with Elbit Systems, who have been significantly involved in Gaza.
"A form of systemic madness is now at play in global politics."
The robust speech concluded with some dark humour courtesy of the situation in Australia, where the government "under Mr Albanese, not a climate fan, announced that for three hours every day every Australian would get their electricity for free". The scheme, based on solar sharing, works because Australia gets so much sunshine that the wholesale price of electricity drops to zero.
"A right-wing party protested that this is 'solar communism'," said Sir Jonathon to discreet laughter in the hall.
"We're going to be living very different lives whether we like it or not," he concluded.
Global carbon emissions from fossil fuels are set to rise 1.1 per cent in 2025 to record highs, research has found.
The latest annual analysis from the global carbon budget project finds that many countries are shifting to clean energy, but that is not enough to offset the growth in global energy demand, leading to an increase in oil, coal and gas burning which generate climate-warming emissions.