Things change……

The world has a better chance of saving itself from catastrophic global warming now than at any time over the past two decades, according to the scientist behind some of the most alarming predictions ever made for the planet’s future.

Johan Rockström shocked environmentalists in 2009 when he identified nine categories of Nature that were essential for life as we know it, and warned that we had already crossed into dangerous territory on three of them – including climate change.

Rockström, an environmental science professor at Stockholm University and executive director of the Stockholm Resilience Centre, has since transferred a fourth category, deforestation, to his list of “planetary boundaries” in the danger zone, which threaten irreversible, devastating consequences to the planet.

But he has had a dramatic change of heart over global warming, and is more optimistic that the worst of the threat can be contained than he has been since 1992.

His optimism is founded on the breakneck speed of innovation in wind and solar power in the past two to three years, which means that renewable energy is being deployed on a massive scale and, crucially, at a cost roughly comparable to fossil fuels. Only last week new figures showed that the cost of electricity produced by onshore windfarms in the UK has fallen so much that for the first time it is now cheaper than fossil-fuel energy.