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?

Photo: Getty
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Like it or hate it, it doesn't matter: Brexit is happening, and we've got to make a success of it

It's time to stop complaining and start campaigning, says Stella Creasy.

A shortage of Marmite, arguments over exporting jam and angry Belgians. And that’s just this month.  As the Canadian trade deal stalls, and the government decides which cottage industry its will pick next as saviour for the nation, the British people are still no clearer getting an answer to what Brexit actually means. And they are also no clearer as to how they can have a say in how that question is answered.

To date there have been three stages to Brexit. The first was ideological: an ever-rising euroscepticism, rooted in a feeling that the costs the compromises working with others require were not comparable to the benefits. It oozed out, almost unnoticed, from its dormant home deep in the Labour left and the Tory right, stoked by Ukip to devastating effect.

The second stage was the campaign of that referendum itself: a focus on immigration over-riding a wider debate about free trade, and underpinned by the tempting and vague claim that, in an unstable, unfair world, control could be taken back. With any deal dependent on the agreement of twenty eight other countries, it has already proved a hollow victory.

For the last few months, these consequences of these two stages have dominated discussion, generating heat, but not light about what happens next. Neither has anything helped to bring back together those who feel their lives are increasingly at the mercy of a political and economic elite and those who fear Britain is retreating from being a world leader to a back water.

Little wonder the analogy most commonly and easily reached for by commentators has been that of a divorce. They speculate our coming separation from our EU partners is going to be messy, combative and rancorous. Trash talk from some - including those in charge of negotiating -  further feeds this perception. That’s why it is time for all sides to push onto Brexit part three: the practical stage. How and when is it actually going to happen?

A more constructive framework to use than marriage is one of a changing business, rather than a changing relationship. Whatever the solid economic benefits of EU membership, the British people decided the social and democratic costs had become too great. So now we must adapt.

Brexit should be as much about innovating in what we make and create as it is about seeking to renew our trading deals with the world. New products must be sought alongside new markets. This doesn’t have to mean cutting corners or cutting jobs, but it does mean being prepared to learn new skills and invest in helping those in industries that are struggling to make this leap to move on. The UK has an incredible and varied set of services and products to offer the world, but will need to focus on what we do well and uniquely here to thrive. This is easier said than done, but can also offer hope. Specialising and skilling up also means we can resist those who want us to jettison hard-won environmental and social protections as an alternative. 

Most accept such a transition will take time. But what is contested is that it will require openness. However, handing the public a done deal - however well mediated - will do little to address the division within our country. Ensuring the best deal in a way that can garner the public support it needs to work requires strong feedback channels. That is why transparency about the government's plans for Brexit is so important. Of course, a balance needs to be struck with the need to protect negotiating positions, but scrutiny by parliament- and by extension the public- will be vital. With so many differing factors at stake and choices to be made, MPs have to be able and willing to bring their constituents into the discussion not just about what Brexit actually entails, but also what kind of country Britain will be during and after the result - and their role in making it happen. 

Those who want to claim the engagement of parliament and the public undermines the referendum result are still in stages one and two of this debate, looking for someone to blame for past injustices, not building a better future for all. Our Marmite may be safe for the moment, but Brexit can’t remain a love it or hate it phenomenon. It’s time for everyone to get practical.