When temperatures were last between 1 and 2 degrees higher than they are now, 125,000 years ago, sea levels were 5 or 6 metres higher. All this extra water, which has since been locked away in the polar caps, is now melting.

Greenland will tip into irreversible melt once global temperatures increase by only 1.2 degrees and the whole Greenland ice sheet would vanish within 140 years. Miami would disappear, as would most of Manhattan, London, Bangkok, Bombay and Shanghai. As glaciers disappear they will cease to power massive rivers that deliver vital fresh water. Drought would ensue and, as ecosystems everywhere unravel, more than a third of all life on Earth will face extinction by 2050.