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Geoengineering: do we intervene?

A major study published today in the United Kingdom asks what role proposed geoengineering technologies could play in regulating the climate. Tan Copsey spoke to one of its contributors, Ken Caldeira.

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As part of a series for chinadialogue that examines the environmental and political arguments around geoengineering, Tan Copsey spoke to Ken Caldeira, senior scientist at the Department of Global Ecology at the Carnegie Institution and a leading expert in “climate emergency response research”. Caldeira is a contributor to the study published today by the Royal Society, Geoengineering the Climate: Science, Governance and Uncertainty, which asks whether planetary-scale geoengineering schemes could play a role in preventing the worst effects of climate change.

Tan Copsey (TC): What geoengineering ideas do you think are being considered seriously by scientists?

Ken Caldeira (KC): I think it is useful to approach this question by asking what problems are we trying to solve. If we are trying to solve the problem of increasing climate risk and climate damage, then we need to consider transforming our energy system first. If we are concerned with catastrophic climate change, then that pushes us towards other techniques.

If we look at the IPCC [Intergovernmental Panel on Climate Change] predictions for global temperature over the century, in every scenario the world continues to warm. So the question is: if rainfall patterns shift such that we are no longer able to grow food properly for the world, or Greenland starts sliding into the sea, raising sea levels rapidly, or if methane starts catastrophically re-gassing from the Siberian frozen grounds, what would we do? This leads us to think about options that could be deployed very rapidly to cool the earth.

I think the leading candidate is to emulate what major volcanoes do, which is to put huge amounts of small particles into the stratosphere, where they can deflect sunlight back into space. We know this works, because after Mount Pinatubo erupted in 1991, the earth cooled about half a degree Celsius. It would have probably cooled three, four, or maybe five degrees had that amount of material been maintained in the stratosphere. While these are very risky types of things to do, I think that in a climate emergency situation we might have to deal with those risks.

There are other options that make some sense: one of them is the idea of whitening clouds by spraying sea water through the air. This forms tiny little salt particles that increase the whiteness of marine clouds [reflecting light back into space].

I think these are really the two options that have the most plausibility. Most other options are either too difficult or expensive – like the idea of putting satellites into space between the earth and the sun, which would be a huge and difficult engineering undertaking.

TC: Do you think that someone will need to deploy forms of geoengineering in our lifetime?

KC: I am uncertain about how bad climate change is going to be for humans. I think it is pretty clear that if you are a polar bear or a coral reef, your days are numbered unless we radically change our emission patterns very soon.

Climate change is clearly an issue for some ecosystems and it is probably an existential issue for some people who are already at the margins, where climate change could push them over the edge. But what climate change will mean for middle-class people, both in the developing and the developed world, I think is highly uncertain. There are some people, like Jim Lovelock, who think society is like a house of cards – climate change will shake the bottom of it and the whole thing might tumble down. With the recent economic crisis, we see some mortgage defaults in the United States leading to a worldwide economic downturn, so it may be that small disruptions will be amplified to have dramatic social consequences. On the other hand, society might be resilient, and humans might be adaptable, like rats and cockroaches.

Although I don’t know how bad climate change is going to be for humans, I do know that there is at least the possibility of devastating consequences – so it just seems to me it makes sense that we have an insurance policy. We should be thinking about these outcomes, what might happen – and if they do happen, what might we do about them.

TC: Do you think there is a risk in talking about geoengineering as a solution – or part of a solution – to climate change, because it reduces the pressure on governments to act to reduce greenhouse-gas emissions?

KC: In this area of climate engineering, or climate intervention, there are at least two political threads. There are people who say if we reduce the risks associated with climate change, then we reduce the incentive to do something about emissions. And there are people who advocate these options in the hope that it will deflate pressure to reduce emissions. But there are other people, such as myself, who think that we need to take the threat of a climate crisis seriously. If you take that threat seriously, then you will think that we need to do what we can to reduce that risk by reducing emissions. But that’s not going to reduce the risk to zero.

TC: Climate change is a global problem and its effects will be unevenly distributed across the world. Could action by a single nation ever be countenanced?

KC: I think this is a difficult question. It’s easy to say that nobody should ever deploy one of these systems without getting global consensus – and in measured times that is what we would do. But let’s say we had a situation where climate change was causing massive crop failure in China: what if Chinese scientists figured that if they intervened in the climate system by putting particles in the stratosphere, and this would likely restore the rains to China and allow China to feed its people once again? If the Chinese leaders thought that they would be saving many millions of lives by putting particles in the stratosphere, it’s hard to imagine that a Chinese leader would say: “No, I’m going to let my people starve because I can’t achieve international consensus.” I think in the case of an emergency, where a political leader thinks it could potentially save many millions of lives, it’s hard to see how that leader could allow their people to starve or die. I could envision a situation where political leaders might deploy these systems in the absence of a worldwide consensus.

That said, I think that it’s important for us to get our governments to start discussing these issues and develop governance and regulation over these technologies to try to make sure that as much as possible there are international controls and consensus over how these tools are used. But I think when push comes to shove and a political leader has their back against the wall, they may feel compelled to deploy these things unilaterally.

TC: But surely ending a drought in one country – in China, for instance – by putting particles in the stratosphere might increase the adaptation burden in another country, such as India.

KC: Yes. In fact after the Mount Pinatubo eruption in 1991, the Ganges River had its lowest flow rates on record – and so we could very easily imagine that putting a bunch of aerosols into the atmosphere might affect the rains in the Ganges River basin. I think it’s possible that if one country or region is in crisis, and one of these systems is deployed, then another region could very well be damaged. We don’t know enough yet to be able to predict “who and when and how”, but this kind of scenario seems likely. The idea that everybody is going to uniformly benefit from the application of these approaches is not at all clear.

This gets back to the governance issue: would whoever did this be liable for compensating people who were affected? There is a parallel to storm modification research in the United States in the 1960s: scientists were looking at steering hurricanes away from major cities. They eventually stopped the research for fear of liability issues – if you directed a hurricane away from a major city and hit some rural area instead, then even though you might have reduced damage overall, the people you did hit with the hurricane would sue you for damages, especially in the US, where we are very litigious. So I think these kinds of issues could occur on a larger scale.

TC: It sounds like this would make it even more difficult for anyone to reach a global decision on geoengineering. How would you come to an agreement? Is it possible?

KC: I think that these things will not be used except in times of extreme emergency. The idea that you would use these options instead of emissions reduction does not make sense given how great all these political, legal and risk factors are. We just wouldn’t be able to deploy these systems in the normal course of policy or get international agreements that it’s a good thing to do. But I think if Jim Lovelock’s vision of climate change turns out to be right, then I think people might be more eager for something that could cool things off rapidly.

TC: Do you see geoengineering as an expanding discipline? Is there funding to pursue this kind of research?

KC: There are no programmes yet in any country to fund this research. I think we may need to re-conceptualise what the field of research is, away from focusing on specific tools and more onto climate emergency response research – and to say that if the worst did happen, what would we do? We shouldn’t get into a situation where we only have a bunch of people developing technologies just for the sake of it.


Ken Caldeira is senior scientist at the Department of Global Ecology at the Carnegie Institution.

Tan Copsey is development manager at
chinadialogue.

Geoengineering the Climate: Science, Governance and Uncertainty,
a policy report from the Royal Society, is published today.

Homepage image from the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

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评论 comments

Default avatar
匿名 | Anonymous

火山爆发

火山一旦爆发,大量的火山灰喷到空中,这样的确会起到遮蔽阳光、从而降低气温的作用,但问题是,火山爆发作为一种自然现象,我们能决定它何时发生吗?作者说的“发挥大型火山的作用”,人们到底应该如何去具体实施这个设想呢?

Volcanic eruption

Large amounts of volcanic ash spout to the air during a volcanic eruption, which deflects sunlight back into space and lowers the temperature.

As a natural phenomenon, however, can we intervene and choose the time when we'd like to see it happen? Given the author's emphasis of those major volcanoes, how should we do to turn this proposal into practice?

(Translated by Tian Liang)

Default avatar
匿名 | Anonymous

喷洒海水

这个空中喷洒海水的主意,跟人工降雨很像,不过对象不是大地,而是白云。我想知道,是要给全球范围内的云层都喷洒海水,还是有选择性地在部分区域这么做?

Spray the seawater in the air

The idea of aerial spraying seawater in the air looks similar to artigificial rainfall. Only the object is not the land but the cloud. I'm wondering that if it is applied to worldwide cloud, or just in a selective area?

Translated by Tian Liang

Default avatar
匿名 | Anonymous

地球工程-一场政治干扰

正如这篇文章所描述的,地球工程是一场危险的政治干扰。我想要补充的是碳补偿(包括减少森林砍伐和林地退化造成的碳排放)也属于政治干扰。

然而,我不认为国家领导人会让他们的人民受到危险。几百万人在斯大林统治时期死亡,在大跃进时丧生,更不用提第一次世界大战了。也就是说,如果我们不大幅度地减少碳排放量,那么面临威胁的人口和其他生物物种数量会越来越大。

本评论由张靓翻译。

Geo-engineering - a political distraction

As this article well describes, geoengineering is a dangerous political distraction. I would add that carbon offsets (including REDD) is too.

However, I disagree that national leaders will jeopardise their populations, millions died in Stalin's era as did millions further east during the Great Leap Forward - not to forget the First World War. That said, the number of humans now at risk unless we radically reduce our carbon emissions is much greater - and we should not forget other species.

Default avatar
匿名 | Anonymous

回应3号

我认为REDD应该是政治干扰,但实际上,它有助于减缓气候变化和森林保护。但是,关键是如何来设计REDD机制,政治领导人应该使REDD用于保护而不是剥削。

评论由Jennifer Yip翻译

Response to No. 3

I think REDD should be political distraction, but, indeed, REDD will benefit the Climate Change Mitigation and Forest Conservation. But, the key is how to design REDD mechanism, The political leaders should make REDD working for Conservation rather than Exploitation.

Default avatar
匿名 | Anonymous

回应3号

我们得承认像CDM、REDD这些机制都带有政治性因素,夹杂着经济利益的意图,这是不可避免的。在现实中,不同群体有着不同的利益诉求,这是人类社会发展的正常现象。
具体到碳减排机制,这些人为设计的机制本身就是政治博弈的产物(利益的交换是无处不在的),但是,我们更应看到它们带来的减缓全球变暖趋势的客观作用,尤其给发展中国家带来的巨大帮助。

Response to No.3

We should acknowledge that those mechanisms,such as CDM and REDD,are influenced by political factors pursuing the economic interest.
This is inevitable. In reality,it is normal that different groups have different concerns in human development history.

As for carbon reduction, these machanims are designed by policy makers as a result of political game in nature(exchange and compromise exist everywhere). What's more, however, is that they have played an objective role in alleviating the global warming crisis.It also helps the developing countries a lot.
Translated by Tian Liang