Glasgow | British Prime Minister Boris Johnson’s ability to pull off a successful COP26 summit looks to be resting precariously on hopes that the big hold-out countries such as China and India might pull surprise new commitments out of the bag.

Stepping up his pre-summit rhetoric as he stood in front of the semi-ruined Roman Colosseum in Italy on Saturday (AEDT), Mr Johnson warned that a global failure to avert climate change could plunge modern society into the kind of civilisational collapse seen in antiquity.