One unadvertised consequence of the Eyjafjallajökull eruption will be a very slight delay in global climate change. The much bigger eruption of Krakatoa in 1883 threw up a cloud of ash that cut sunlight reaching the Earth by 1 per cent, produced half a decade of exceptionally cold winters worldwide and had a cooling effect on the oceans that was still apparent a century later.
All of which underlines that there are things other than reducing greenhouse gas emissions that we can do to combat the planet’s warming. Such techniques go under the collective name of geoengineering. Possibilities range from the uncontentious (growing more trees) through the implausibly difficult (painting the roofs of all buildings on the planet white or covering the deserts with aluminium foil) to the frankly futuristic (installing mirrors in space to reflect away sunlight).
But some merit further examination, such as “seeding” clouds to make them whiter and so more reflective; fertilising the ocean’s plankton so it consumes more CO2; and spreading sulphur particles in the upper atmosphere to reflect sunlight in exactly the manner of an erupting volcano.
Even contemplating such possibilities raises sharp questions. This is playing with the environment on a grand scale. There could be catastrophic side-effects. While the global climate may be tamed, there could be regional variations even worse than the problem that we are trying to fix. Above all, how would these techniques be managed? Whose hand would be on the thermostat?
So why think about geoengineering at all? The answer is clear: our current approach to climate change is failing. Twenty years of negotiation (in a lot of which I was personally involved) have produced two treaties that glaringly failed to halt the rise in greenhouse gas emissions. We cannot be confident that the third, the Copenhagen Protocol, will do any better.
The difficulties were underlined for me at an ambassadorial lunch in Washington in 2001 where the US National Security Adviser told us that the Kyoto Protocol was “dead on arrival”, and in 2005 when President Putin’s chief economic adviser told me that he welcomed global warming because it opened up an ice-free Arctic and a vast new area for oil exploration.
With China alone now installing more (mostly coal-generated) electricity generating capacity every year than the UK’s entire stock. We clearly need to look at the “third way” that geoengineering may offer.
For, despite the obvious dangers, geoengineering has attractions. Some of its techniques — salting the ocean or seeding the atmosphere — could act fast enough to keep us below the two-degree threshold beyond which real climatic disaster is thought to lurk. And it is (relatively) cheap. A few well- placed ounces of sulphur in the upper atmosphere is equivalent to a saving of several hundred tons of CO2. In politics, cheaper always means easier.
But discussion has barely begun on perhaps the biggest problem: governance. In only a few years, the global climate may be subject to unilateral manipulation. The financial and technical capacity to seed the upper atmosphere may be within the capacity of a single big state (the US, Russia or China) or a group of medium-sized states (such as the EU). While the image of the US or China setting the planetary thermostat at a level optimal for them may look deeply implausible today, it will become more likely the longer we fail to prevent the global climate from sliding towards catastrophe.
It is difficult to think of a precedent for the challenge this poses. Perhaps the closest is the emergence of nuclear weapons in the 1940s and 1950s. Then, as now, a few states had the power to take unilateral actions with very widespread effects. It is comforting that the international system has (so far) managed that with astonishing success. The parallel is, of course, inexact. While the bomb is a deterrent that no power seriously wants to use unless forced to, geoengineering could be an option that we decide we really need to employ.
But the pattern of international agreements on nuclear weapons offers a guide. These combine an effectively global agreement designed to restrain proliferation and keep the technology in as few hands as possible with a web of specific agreements among the nuclear-weapons states designed to maximise transparency, create predictable behaviour, limit warhead numbers and generally minimise the likelihood of a runaway arms race or nuclear war by accident.
This pattern is attractive because the big players in geoengineering will not be willing to place control of a technology vital for their future national prosperity into the hands of (as we saw in Copenhagen) a disputatious, fragmented, gridlocked UN. The most that is likely to be achievable on a global level are agreements on transparency, consultation and care in the examination and testing of techniques.
States that deploy this technology will be more concerned to reach agreement with other potential deployers, both to get a grip on the likelihood of deployment and, if possible, to share the costs of what, even if cheap by comparison with the alternatives, would still be a very expensive set of actions.
These are still early days. But the urgency is increasing. The UN climate change process should start now examining the implications of geoengineering. More importantly, the G20 — the club of nations most likely to use geoengineering — should be discussing the ground rules before the pressure to take decisions becomes acute. This is a technology we may well need to turn to. Let’s make sure we are ready if the time comes.
By Tony Brenton, a British diplomat from 1975 to 2009, most recently serving as Ambassador to Moscow.