Another day, another climate expert explains the deadly combination of inaction and faster-than-expected impacts.

This time the man ringing the bell is Lord Nicholas Stern, the author of the famous Stern Review on the Economics of Climate Change. The UK Guardian reports:

Stern … said: “Looking back, I underestimated the risks. The planet and the atmosphere seem to be absorbing less carbon than we expected, and emissions are rising pretty strongly. Some of the effects are coming through more quickly than we thought then.”

The Stern review, published in 2006, pointed to a 75% chance that global temperatures would rise by between two and three degrees above the long-term average; he now believes we are “on track for something like four “. Had he known the way the situation would evolve, he says, “I think I would have been a bit more blunt. I would have been much more strong about the risks of a four- or five-degree rise.”

A 4° to 5°C (7° to 9°F) increase would be catastrophic (see World Bank Climate Report: ‘A 4°C [7°F] World Can, And Must, Be Avoided’ To Avert ‘Devastating’ Impacts). Stern continues:

“This is potentially so dangerous that we have to act strongly. Do we want to play Russian roulette with two bullets or one? These risks for many people are existential.”

Stern was not alone in raising concerns at the World Economic Forum:

Stern’s comments came as Jim Yong Kim, the new president of the World Bank, also at Davos, gave a grave warning about the risk of conflicts over natural resources should the forecast of a four-degree global increase above the historical average prove accurate.

“There will be water and food fights everywhere,” Kim said as he pledged to make tackling climate change a priority of his five-year term.

The time to act was a long time ago but now is infinitely, existentially better than later.