As world leaders assemble for the United Nations climate change conference (COP27) in Egypt, it’s hard to be optimistic the talks will generate any radical departure from the inexorable rise in global carbon emissions over the past two centuries. After all, before last year’s Glasgow talks, experts warned the summit was the world’s last chance to limit global warming to 1.5℃ this century. And yet, a UN report last week found even if all nations meet their climate goals this decade, the planet would still heat by a catastrophic 2.5℃.