Science in Society Archive

GeoEngineering A Measure of Desperation

We have all the means to save the climate without risking the earth in unregulated geoengineering research Prof. Peter Saunders and Dr. Mae-Wan Ho

Unilateral ocean fertilisation

The German research vessel Polarstern is on its way to spread ferrous sulphate over a 400 sq km area of the South Atlantic [1] ( Saving the Climate Dangerously , SiS 41). This raises serious concerns, not just over this particular experiment; but over geoengineering research in general (see fig. 1), which targets the earth's own regulatory dynamics that keeps its climate fit for life [2] (see Life of Gaia series, SiS 20). Such projects are inevitably speculative; t he perceived benefits uncertain and risks enormous. Yet there is no provision for international regulation. The decision for the experiment to go ahead was taken not by a UN body but by the German Minister of Science, and only after there had been protests.

There isn't an urgent need to develop such projects to save the climate. It is widely accepted that we have all the means at our disposal to solve t he problem: reduce the amount of energy we use, replace fossil fuels with renewable energy sources, switch to organic, localised food systems , stop the destruction of forests and replace some of those we have lost [3, 4] ( Which Energy? , Food Futures Now: *Organic *Sustainable *Fossil Fuel Free , I-SIS Publications). So why take the risk?

Figure 1. GeoEngineering, from Lawrence Livermore National Laboratories.

The proponents of geoengineering argue that conventional methods may not be enough. We have underestimated the speed of climate change. The polar ice caps are melting faster than expected. The more sophisticated the climate models, the more dire the predictions they make; it turns out there are many positive feedbacks that make things spiral out of control. For example, as the Earth becomes warmer, permafrost melts, releasing large amounts of methane into the atmosphere and so increasing the warming even further. Worse still, positive feedbacks tend to be accompanied by tipping points; for the climate this would mean a temperature beyond which the rate of increase would be much faster than even the most pessimistic forecasts.

And even if conventional methods are enough to save us, they may not be implemented through sheer lack of political will. The UK government has said a great deal about climate change – it was Gordon Brown who commissioned the Stern report (see The Economics of Climate Change , SiS 33 [5]) – but nevertheless is ho lding down the petrol tax, and has approved the third runway of London's Heathrow Airport. There is at least an argument for investigating other measures, and indeed a number of groups are working on them. (For an accessible and authoritative account see Stephen Schneider's 2008 review in the Philosophical Transactions of the Royal Society [6]).

Geoengineering to save the climate

A number of scientists, noting that a great deal of carbon is already sequestered in the oceans, have been experimenting with fertilising the ocean with iron so as to stimulate phytoplankton blooms. Others propose releasing drops of sea water into the atmosphere to make the clouds over the ocean whiter and so reflect more of the sun's energy back into space. Alternatively, dust particles could be injected into the stratosphere to help shield us from the sun.

Another strategy is to reduce the amount of the sun's energy that reaches the Earth. One proposal is to place a cloud consisting of trillions of spacecraft at a point in space (the “inner Lagrange point”) where it would remain stationary because the centrifugal force would be exactly balanced by the gravitational attractions of the Sun and the Earth. The cloud would be about 60 000 miles long and would reduce sunlight by about 2 percent, which it is claimed could balance the heating effect of a doubling of CO 2 .

Alternatively, because the sun's radiation is about eight times as intense in space as on the surface of the Earth, we might be able to reduce our dependence on fossil fuels by constructing a solar power station in space. The energy would be transmitted to the Earth by microwaves.

Stranger dangers

While there are reasons for investigating these possibilities, there are also dangers. In the first place, many of these proposals are for very large projects and impose correspondingly large opportunity costs. If we waste billions of dollars on some scheme that doesn't deliver, that's money that could have been spent on measures that are less dramatic but more effective.

There is also a political opportunity cost. A major project gives governments and others with power an excuse for not supporting more conventional measures. Why risk alienating motorists and the oil industry by raising the tax on petrol if ten years from now some technological breakthrough will solve all our problems? George Bush was one of the few world leaders to use the argument explicitly, but it obviously lies behind a lot of what the others do, or won't do.

A large project also develops a momentum of its own. The longer it has been running, the more reluctant those who are working on it and the government that is paying for it are to abandon it. One of the reasons for dropping the atom bombs on Japan was simply that having put so much effort into developing them, the military authorities were reluctant not to try them out.

The Earth is a highly complex system with many important interactions that keep it in a dynamic equilibrium, most of which we do not really understand. In making a significant change to the system, which is what geoengineering is about, we are all too likely to find ourselves landed with consequences we did not foresee. If, for example, we were to increase the cloud cover over the oceans and this made the seas more acid, we would find it very difficult to put that right. The same objection has been raised to fertilising the oceans with iron, and there is also uncertainty about how long carbon sequestered in this way would remain at the bottom of the sea, or even if it would ever reach the bottom of the sea at all.

What would happen if we put an aerosol into the atmosphere or mirrors into space and they drifted away from where they were put? Even if they remained in place, cooling part of the Earth would be bound to change the circulation both in the atmosphere and in the oceans, with results that are hard if not impossible to predict. Remember that one of the anticipated consequences of global warming is that Great Britain and western Europe are likely to become colder because adding too much fresh water to the northern part of the Atlantic will halt the North Atlantic thermohaline circulation system that is responsible for pushing warm water from the tropics to the shores of north western Europe.

Many researchers working on these proposals are obviously very conscious of the uncertainty and the potential for harm. But, as the voyage of the Polarstern shows, we cannot rely on individual restraint or existing international agreements to keep us safe from the premature use of geoengineering. An international climate change authority might well opt for some geoengineering proj ect as a result of lobbying by oil companies, the aviation industry and others who stand to lose from reductions in the use of fossil fuels. Furthermore, just as with nuclear weapons, countries might go ahead unilaterally if they thought a project would favour them at the expense of others, or else because of misplaced confidence in the technology.

Measure of desperation

Proponents argue that because we cannot be sure conventional methods are effective, or that they will be deployed in time , it is worth carrying out research into less well understood and therefore riskier technologies, and hope we never have to resort to them. This may seem a sensible way forward given the adverse political climate; but it is a measure of desperation. And it must be placed under the strictest legal oversight and regulation of an appropriate international body.

Meanwhile, all the evidence indicates that we can keep climate change within tolerable limits by more conventional methods, especially by the widespread adoption of Organic Agriculture and Localized Food & Energy Systems for Mitigating Climate Change [7] ( SiS 40).

Article first published 04/02/09


  1. Saunders PT. Saving the climate dangerously. Science in Society 41,
  2. Ho MW, Bunyard P and Burcher S. Life of Gaia series. Science in Society 20 , 20-33. 2003.
  3. Ho MW, Bunyard P, Saunders PT, Bravo E and Gala R. Which Energy? I-SIS Energy Report, ISIS, London , 2006,
  4. Ho MW, Burcher S, Lim LC, et al . Food Futures Now, Organic, Sustainable, Fossil Fuel Free , I-SIS and TWN, London, 2008
  5. Saunders PT. The economics of climate change. Science in Society 33 , 20-23, 2007.
  6. Schneider SH. Geoengineering: Could we or should we make it work? Philosophical Transactions of the Royal Society A 2008. Published on line: doi:10.1098/rsta.2008.0145
  7. Ho MW. Organic agriculture and localised food and energy systems for mitigating climate change. Science in Society 40 , 24-28, 2008.

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