Communication Division

The world as a workshop

Steadily increasing emissions of greenhouse gases are compelling researchers to take a closer look at one of the last taboos left in science.

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Text: Eivind Senneset

Artificial volcano eruptions? A fleet of 1,500 ships pumping saltwater up into the atmosphere in order to form whiter clouds? Sixteen thousand billion small spaceships that block the sunlight? So-called geoengineering is the science that looks at ways of counteracting climate changes by changing the climate. Such tampering with the thermostat has long been one of the climate debate’s last remaining taboos. But in the course of this year, both the Royal Society in the UK and the American Meteorological Society in the USA began to support research in this field.

‘More and more people are realising that far-reaching climate changes are an unavoidable fact of life. So then you have to look at the available alternatives,’ says Helge Drange of the Bjerknes Centre for Climate Research.

Sober pessimism

Manipulating the Earth and its climate is not only a field of study that operates right on the borderline between science and science fiction; it is also a discipline that poses some of the most difficult ethical and moral questions ever faced by science. It has long been a widespread belief among serious climate researchers that even discussing climate manipulation is damaging: ‘There's a fairly widespread feeling that even studying it lends it a certain legitimacy, and that that legitimacy could be used as a rhetorical tool – or even as a basis for real-world programs – by people who have no interest in reducing CO2 emissions,’ writes Oliver Morton in Nature’s blog

In other words, it is ethically speaking more correct to prevent climate changes by changing our way of life than changing nature in order to compensate for the consequences. But what if there are no either-or alternatives for preventing potentially catastrophic climate changes on a global scale? While Plan A continues to be to reduce emissions of greenhouse gases, we see few or no indications that this plan will not prove to be a complete failure. Emissions of CO2 are increasing year by year. Even the G8 leaders’ recently agreed emission cuts entail a further increase in the CO2 level in the atmosphere. Even at today’s level we are facing a temperature rise that could be as much as four degrees Celsius compared with the average before the industrial revolution. And long before that happens, nature’s own self-reinforcing mechanisms will have kicked in.

‘Like it or not, climate manipulation is a Plan B that we have to make a decision on,' says Helge Drange.

A cloud of mirrors

With heavy hearts, more and more climate researchers are reporting that the lack of political will is now making it absolutely necessary to conduct research into climate manipulation. So, what alternatives do we have? How effective are they? And how bitter will the medicine taste? In January, Professor Tim Lenton and his student Naomi Vaughan at the University of East Anglia published an article in the journal Atmospheric Chemistry and Physics in which they ranked the different climate manipulation proposals on the basis of their ability to slow down global warming.

Only three proposals have the capability of dealing with a doubling of today’s CO2 levels. One of them sounds like something out of a crazy science fiction novel, the second would make things as cold as ice in Norway, and the third could change the world's precipitation systems. Roger Angel’s plan would cost 5,000 billion dollars, and that amount includes economies of scale and technology that does not exist yet. With today’s technology and price levels it would cost a thousand times more just to send the spaceships with mirrors out into space, where they are supposed to prevent sunlight from reaching the Earth. But the professor at the University of Arizona envisages an electromagnetic cannon that can send almost a million spaceships into space. Every minute. For thirty years.

A 100,000-km-long cloud of these space ships carrying mirrors, strategically situated between the Earth and sun, would prevent about 2% of the sun's energy from reaching our atmosphere. This would compensate for a temperature increase equivalent to that caused by a doubling of today's CO2 level. The advantage of Angel’s plan is that it is relatively predictable; unlike other climate manipulating proposals, it does not affect the atmosphere’s chemical composition. The disadvantage, of course, is the realism of the project.

‘We don't have much time  to solve the climate crisis, so I think that it would perhaps be smart to start by shooting sulphur dioxide up into the atmosphere,’ said Roger Angel to the newspaper Dagens Næringsliv earlier this year.

Acid rain in Norway


Waste gases such as sulphur dioxide produce aerosols in the atmosphere. They can also reflect sunlight and reduce the temperature on the ground. We are familiar with this effect from volcanic eruptions. The Mount Tombora eruption in Indonesia in 1815 probably caused the ‘year without summer’ the following year. This effect is the starting point for a form of climate manipulation whereby sulphur dioxide is pumped into the atmosphere. This proposal could save the world from a climate catastrophe, but it could cause a new one, because this waste gas also causes acid rain, health problems and, most likely, new holes in the ozone layer. The question is whether or not it is worth it. Ken Caldeira of Stanford University believes it is. The proposal would cool down the areas most in need of being cooled down and could prevent the Greenland ice sheet from melting. Moreover, the negative effects would mainly be felt in the northern regions. While we Norwegians live in this region, the majority of the world’s population does not. Engineering professor Stephen Salter and physicist John Latham may have found a solution that is less dependent on the Norwegians’ spirit of self-sacrifice. They envisage a fleet of 1,500 ships that would pump 1.4 billion tonnes of seawater into the troposphere every year. This would create whiter clouds that would reflect more of the sunlight out into space. It may be possible for this plan to be realised in only five years’ time, and it could keep the climate changes in check for around 75 years – but it could also cause frost pockets and change the world’s precipitation systems.

‘Temporary solution’

Because little research has been done so far on climate manipulation, it is difficult to say with certainty what the side effects would be. Considering how complicated the global climate systems are, it is highly unlikely that we will ever manage to gain a complete picture of all the possible impacts of proposals of this kind. That is why the UN’s climate panel has endorsed the precautionary principle and adopted a fundamentally sceptical attitude. This uncertainty is one of the sceptics’ most important arguments. Another argument is its lack of permanence. Climate manipulation is a temporary cure; it does not get rid of greenhouse gases. If the effect of such a proposal ceases, it would be like a dam bursting, with sudden and powerful warming of the climate as a result.

‘Climate manipulation can help us win time to concentrate on pure energy and emission reductions, but, if we don't do something about the fundamental problem, we would have to maintain the manipulation for an unforeseeable period and implement more and more drastic measures,’ says Helge Drange. Tampering with the thermostat might give us some breathing space – if it doesn’t finish us off first, that is. In any case, there is one small formality that would have to be clarified before we could go ahead with what could be the most daring stop-gap in history and that would affect all life on our planet, all human beings, irrespective of national borders: who actually has a mandate to make such a decision?