Two men sit at a panel in front of a teal backdrop that says United Nations Climate Change. The man on the left is older and scratching his nose, looking bored. The man on the right appears to be in the middle of talking.

A group of former leaders and climate experts say the annual UN COP climate talks are no longer fit for purpose and need to be reformed, publishing a critical open letter mid-way through what has so far been a fractious summit.