We can thank our clouds for saving us from a fate worse than Venus's

Clouds are essential as they reflect and scatter sunlight back into space - but nobody knows how hot the planet can become before the clouds no longer help us.

No one wants to think about cloudy skies in August but if they’re up there, be grateful. According to research published in Nature Geoscience on 28 July, we can thank clouds for saving us from a fate worse than Venus’s.

Venus – a barren, hot planet – suffered from the “runaway greenhouse effect” when its temperature rose past a critical point. That, it seems, arose from having too much thermal insulation resulting from the heat-storing greenhouse gases in the planet’s atmosphere.

On Venus, as on earth, carbon dioxide was an important contributor. Our planet is wet and heating it creates a lot of water vapour, a far more potent insulator than carbon dioxide. The more water vapour there is, the faster warming occurs.

Once you hit the point of no return at which the runaway effect starts, it would take only a few thousand years for life on earth to become untenable.

The recently published calculations show that the Venus effect could happen here – if it weren’t for clouds. They look white and fluffy to us because they scatter light. The tops of the clouds do the same, scattering and reflecting sunlight back into space before it has the chance to warm the earth and take it into the runaway scenario.

There’s still some uncertainty in the calculations, however: we don’t know exactly how hot we can let the planet become before the clouds can no longer help us. Unfortunately, uncertainty in other areas is pushing us in the right direction to find out.

The Intergovernmental Panel on Climate Change (IPCC) will publish its fifth assessment report next year. A draft report of some of its data, leaked to the Economist, suggests that increasing carbon-dioxide levels won’t warm the atmosphere as much as we had previously thought. In 2007, the IPCC stated that concentrations of between 445 and 490 parts per million (ppm) of carbon dioxide were likely to result in a rise in temperature of 2° to 2.4° Celsius above the temperatures before the Industrial Age. The new data suggests that 425 to 485ppm would give a rise of 1.3° to 1.7° Celsius.

The Economist threw in plenty of caveats (“The two findings are not strictly comparable”; the data comes “from a draft version of the report, and could thus change”) but evidently felt the burden of reducing carbon emissions is not as onerous as it once seemed. “It is clear,” the paper declared, “that some IPCC scientists think the projected rise in CO2 levels might not have such a big warming effect as was once thought.”

As it turns out, it’s not just carbon dioxide that we need to worry about. US researchers have been mapping the gas leaks from pipelines in urban areas. Boston has more than 3,000 leaks in the pipelines that deliver gas to homes and industries. Preliminary data from Washington, DC indicates that the capital is just as prone to leaks. It’s of huge concern because methane is 25 times more potent as a greenhouse gas than carbon dioxide. If similar figures apply to every other major city with an ageing gas infrastructure, perhaps the chances of earth slipping into a runaway greenhouse effect need revising upwards.

We can be sure those figures won’t be in the IPCC report, however. As for the ones in the Economist, we’ll just have to wait and see. In many ways, it doesn’t matter: the numbers are out there now and will be put to work by those keen to make sure we don’t punish carbon emitters. Such a leak is not going to make governments feel inclined to do something about the problem – they can just keep their head in the clouds.

Sunset over Tiananmen Square after a day of heavy pollution in Beijing. Photograph: Getty Images.

Michael Brooks holds a PhD in quantum physics. He writes a weekly science column for the New Statesman, and his most recent book is At the Edge of Uncertainty: 11 Discoveries Taking Science by Surprise.

This article first appeared in the 12 August 2013 issue of the New Statesman, What if JFK had lived?

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Michael Gove definitely didn't betray anyone, says Michael Gove

What's a disagreement among friends?

Michael Gove is certainly not a traitor and he thinks Theresa May is absolutely the best leader of the Conservative party.

That's according to the cast out Brexiteer, who told the BBC's World At One life on the back benches has given him the opportunity to reflect on his mistakes. 

He described Boris Johnson, his one-time Leave ally before he decided to run against him for leader, as "phenomenally talented". 

Asked whether he had betrayed Johnson with his surprise leadership bid, Gove protested: "I wouldn't say I stabbed him in the back."

Instead, "while I intially thought Boris was the right person to be Prime Minister", he later came to the conclusion "he wasn't the right person to be Prime Minister at that point".

As for campaigning against the then-PM David Cameron, he declared: "I absolutely reject the idea of betrayal." Instead, it was a "disagreement" among friends: "Disagreement among friends is always painful."

Gove, who up to July had been a government minister since 2010, also found time to praise the person in charge of hiring government ministers, Theresa May. 

He said: "With the benefit of hindsight and the opportunity to spend some time on the backbenches reflecting on some of the mistakes I've made and some of the judgements I've made, I actually think that Theresa is the right leader at the right time. 

"I think that someone who took the position she did during the referendum is very well placed both to unite the party and lead these negotiations effectively."

Gove, who told The Times he was shocked when Cameron resigned after the Brexit vote, had backed Johnson for leader.

However, at the last minute he announced his candidacy, and caused an infuriated Johnson to pull his own campaign. Gove received just 14 per cent of the vote in the final contest, compared to 60.5 per cent for May. 


Julia Rampen is the editor of The Staggers, The New Statesman's online rolling politics blog. She was previously deputy editor at Mirror Money Online and has worked as a financial journalist for several trade magazines.