The United Nations’ Conference of Parties (Cop) climate summits are “no longer fit for purpose” and require an urgent overhaul, climate experts and former UN chiefs have said.

The letter, signed by more than 20 experts and leaders, including Ban Ki-moon, the former UN secretary-general, and Christiana Figueres, the ex-UN climate chief, said the annual meeting between nations cannot implement the change required to tackle the climate crisis.

The open letter published during this year’s summit in Baku also called for countries to not host the Cop meeting if they do not support the phasing out of fossil fuels.

It came as Azerbaijan’s president hailed natural gas a “gift from God” in the opening speech of Cop29, before criticising Western media and climate activists.