In 2000, the Hadley centre for climate change released new global warming estimates, based on recently discovered ‘'positive feedback'. An example of positive feedback is when early snowmelt allows more summer heat to go into raising the temperatures of the air and ground rather than melting the snow. This increase in temperature will begin to kill off plant-life and instead of absorbing carbon dioxide the stressed plants begin to emit it.

These new models did not suggest the familiar slow linear increase. Rather than absorbing and retaining greenhouse gases from the atmosphere nature was going to spit them back out again, billions of years worth of carbon and methane, released not gradually but in sudden surges, melting ice in torrents and suffocating the Amazon rainforest by 2050. Rather than simply threatening our way of life a vicious spiral of ‘'positive feedback loops' would drive runaway global warming that would threaten the existence of every other species on Earth.