Boris Johnson warns of new ‘dark ages’ if global warming is not confronted

British Prime Minister Boris Johnson visits the Colosseum during the G20 summit in Rome, Italy (Jeff J Mitchell/PA)

The world could be heading for a new “dark ages” if it fails to tackle global warming, Boris Johnson has warned as he appealed to the world’s leading economies to do more to cut emissions.

Standing in Rome’s Colosseum, the British Prime Minister likened the impact of unrestricted climate change to the fall of the Roman Empire.