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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The buck doesn't stop with Grant Shapps - and probably shouldn't stop with Lord Feldman, either

The question of "who knew what, and when?" shouldn't stop with the Conservative peer.

If Grant Shapps’ enforced resignation as a minister was intended to draw a line under the Mark Clarke affair, it has had the reverse effect. Attention is now shifting to Lord Feldman, who was joint chair during Shapps’  tenure at the top of CCHQ.  It is not just the allegations of sexual harrassment, bullying, and extortion against Mark Clarke, but the question of who knew what, and when.

Although Shapps’ resignation letter says that “the buck” stops with him, his allies are privately furious at his de facto sacking, and they are pointing the finger at Feldman. They point out that not only was Feldman the senior partner on paper, but when the rewards for the unexpected election victory were handed out, it was Feldman who was held up as the key man, while Shapps was given what they see as a relatively lowly position in the Department for International Development.  Yet Feldman is still in post while Shapps was effectively forced out by David Cameron. Once again, says one, “the PM’s mates are protected, the rest of us shafted”.

As Simon Walters reports in this morning’s Mail on Sunday, the focus is turning onto Feldman, while Paul Goodman, the editor of the influential grassroots website ConservativeHome has piled further pressure on the peer by calling for him to go.

But even Feldman’s resignation is unlikely to be the end of the matter. Although the scope of the allegations against Clarke were unknown to many, questions about his behaviour were widespread, and fears about the conduct of elections in the party’s youth wing are also longstanding. Shortly after the 2010 election, Conservative student activists told me they’d cheered when Sadiq Khan defeated Clarke in Tooting, while a group of Conservative staffers were said to be part of the “Six per cent club” – they wanted a swing big enough for a Tory majority, but too small for Clarke to win his seat. The viciousness of Conservative Future’s internal elections is sufficiently well-known, meanwhile, to be a repeated refrain among defenders of the notoriously opaque democratic process in Labour Students, with supporters of a one member one vote system asked if they would risk elections as vicious as those in their Tory equivalent.

Just as it seems unlikely that Feldman remained ignorant of allegations against Clarke if Shapps knew, it feels untenable to argue that Clarke’s defeat could be cheered by both student Conservatives and Tory staffers and the unpleasantness of the party’s internal election sufficiently well-known by its opponents, without coming across the desk of Conservative politicians above even the chair of CCHQ’s paygrade.

Stephen Bush is editor of the Staggers, the New Statesman’s political blog.