Ecologically speaking, a spilt tanker load is like sticking a safety pin into an elephant’s foot. The planet barely notices. After the Exxon Valdez accident in Alaska the oil company spent billions tidying up the coastline, but it was a waste of money because the waves were cleaning up faster than Exxon could. Environmentalists can never accept the planet’s ability to self-heal.

Environmentalists may get off on climate porn, but most people just turn away. 'If it was really so bad, they'd do something,' says one colleague, without specifying who 'they' are. The human tendency to convince yourself that everything is OK, because no one else is worried, is deeply ingrained.