“What’s the point of COP27?” a friend asked the other day of the UN climate talks starting next week in Egypt. “When it comes to climate change, aren’t we doomed?”

That question is often asked ahead of these annual climate gatherings and it always leaves me with a deep sense of cognitive dissonance — the unsettling psychological state caused by holding two conflicting beliefs at once. In this case, bleak pessimism versus unexpected optimism.

The reasons not to be cheerful are obvious. Despite 27 years of UN climate COPs, greenhouse gas concentrations are still rising to record highs. So climate change is already here, its fingerprints literally measurable in the lethal heatwaves, wildfires and floods pounding a globe that has warmed by about 1.1C since the late 1800s.