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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Richmond is a victory for hope - now let's bring change across the country

The regressives are building their armies. 

Last night a regressive alliance was toppled. Despite being backed by both Ukip and the Conservative Party, Zac Goldsmith was rejected by the voters of Richmond Park.

Make no mistake, this result will rock the Conservative party – and in particularly dent their plans for a hard and painful Brexit. They may shrug off this vote in public, but their majority is thin and their management of the post-referendum process is becoming more chaotic by the day. This is a real moment, and those of us opposing their post-truth plans must seize it.

I’m really proud of the role that the Green party played in this election. Our local parties decided to show leadership by not standing this time and urging supporters to vote instead for the candidate that stood the best chance of winning for those of us that oppose Brexit. Greens’ votes could very well be "what made the difference" in this election (we received just over 3,500 votes in 2015 and Sarah Olney’s majority is 1,872) - though we’ll never know exactly where they went. Just as importantly though, I believe that the brave decision by the local Green party fundamentally changed the tone of the election.

When I went to Richmond last weekend, I met scores of people motivated to campaign for a "progressive alliance" because they recognised that something bigger than just one by election is at stake. We made a decision to demonstrate you can do politics differently, and I think we can fairly say that was vindicated. 

There are some already attacking me for helping get one more Liberal Democrat into Parliament. Let me be very clear: the Lib Dems' role in the Coalition was appalling – propping up a Conservative government hell bent on attacking our public services and overseeing a hike in child poverty. But Labour’s record of their last time in office isn't immune from criticism either – not just because of the illegal war in Iraq but also their introduction of tuition fees, privatisation of our health service and slavish worship of the City of London. They, like the Liberal Democrats, stood at the last election on an austerity manifesto. There is a reason that we remain different parties, but that doesn’t mean we shouldn't also seize opportunities like this to unite behind what we have in common. Olney is no perfect candidate but she has pledged to fight a hard Brexit, campaign against airport expansion and push for a fair voting system – surely progressives can agree that her win takes us forward rather than backwards?

Ultimately, last night was not just defeat of a regressive alliance but a victory for hope - a victory that's sorely needed on the back of of the division, loss and insecurity that seems to have marked much of the rest of this year. The truth is that getting to this point hasn’t been an easy process – and some people, including local Green party members have had criticisms which, as a democrat, I certainly take seriously. The old politics dies hard, and a new politics is not easy to forge in the short time we have. But standing still is not an option, nor is repeating the same mistakes of the past. The regressives are building their armies and we either make our alternative work or risk the left being out of power for a generation. 

With our NHS under sustained attack, our climate change laws threatened and the increasing risk of us becoming a tax haven floating on the edge of the Atlantic, the urgent need to think differently about how we win has never been greater. 

An anti-establishment wave is washing over Britain. History teaches us that can go one of two ways. For the many people who are utterly sick of politics as usual, perhaps the idea of politicians occasionally putting aside their differences for the good of the country is likely to appeal, and might help us rebuild trust among those who feel abandoned. So it's vital that we use this moment not just to talk among ourselves about how to work together but also as another spark to start doing things differently, in every community in Britain. That means listening to people, especially those who voted for Britain to leave the EU, hearing what they’re saying and working with them to affect change. Giving people real power, not just the illusion of it.

It means looking at ways to redistribute power and money in this country like never before, and knowing that a by-election in a leafy London suburb changes nothing for the vast majority of our country.

Today let us celebrate that the government's majority is smaller, and that people have voted for a candidate who used her victory speech to say that she would "stand up for an open, tolerant, united Britain".  But tomorrow let’s get started on something far bigger - because the new politics is not just about moments it's about movements, and it will only work if nobody is left behind.

 

Caroline Lucas is the MP for Brighton Pavilion.