In the summer of 2006, geoengineering - the radical proposal to offset one human intervention into planetary systems with another - came roaring out of the scientific closet. Deliberate climate modification, as climate scientist Wally Broecker once noted, had long been “one of the few subjects considered taboo in the realm of scientific inquiry”.
Two things spurred this dramatic reversal: growing alarm because climate change was hitting harder and faster than expected and the abysmal failure of political efforts to reduce carbon dioxide emissions. Indeed, since world leaders signed the Rio Convention on Climate Change in 1992, global emissions climbed from 6.1 billion metric tons of carbon a year to 8.5 billion tons in 2007. Dismayed by the inaction, Paul Crutzen, a Nobel laureate, published a controversial paper in August, 2006 that opened the door to the hitherto unthinkable. Since timely and sufficient reductions appeared to be, in his words, “a pious wish”, he urged serious investigation of technological proposals to offset rising temperatures.
For some, geoengineering seemed to hold out another hope: that technology might provide an escape not only from growing heat, but also from the thorny realm of hard choices and difficult international politics. Those politics were on vivid display in Copenhagen recently, as nations have agreed on the gravity of the threat but little else.
Since the release of Crutzen’s influential paper, many have voiced concerns about possible hazards posed by geoengineering schemes. For example, the artificial volcano projects, which would inject sulphate particles into the stratosphere to deflect incoming sunlight, might reduce the symptom of excess heat, but experience from past volcanic eruptions and climate models indicates that this approach would likely alter rainfall patterns and intensify drought in many regions. And because such sunshade schemes only treat a symptom rather than tackle the cause, this technofix would do nothing to prevent another dire consequence of rising levels of carbon dioxide in the atmosphere - increasing acidity in ocean waters. This acidity jeopardises coral reefs, shelled marine life, and a tiny plankton Emiliania huxleyi, which plays a key role in the transfer of carbon from the atmosphere to long-term storage in deep ocean sediments.
But the biggest hitch in sunshade remedies involves politics and questions of governance, for they would require an unflagging commitment of centuries: 500 years or so, or, if we do not make major emissions cuts, even as long as a millennium. If anything were to interrupt this geoengineering effort, which would have to keep replenishing the sulphates every few years, the world would quickly confront a doomsday scenario: temperatures would suddenly soar upward at a rate 20 times faster than they are rising today, causing unimaginable havoc in human and natural systems and with it, the real danger of human extinction.
This institutional challenge is without question a far greater obstacle than any technological difficulties. It is hard to imagine that anyone with even a passing knowledge of human history would think this long-term commitment could be a prudent gamble.
The moral and political hazards of geoengineering are altogether as formidable as the physical dangers. However inviting the prospects shimmering on the technological horizon, geoengineering “solutions” and the promise of a technoﬁx down the road lead us easily into temptation. Indeed, these speculative technologies are already figuring in the political debate and hover in the background of diplomatic discussions, since it will be impossible to limit future warming to 2 degrees C, as G8 leaders pledged in July, without something like a new technology to suck carbon dioxide from the atmosphere. It is easy to forget that these are proposals, not proven technologies. There is no assurance that any will actually work as imagined.
Even more troubling, these tantalising prospects can encourage neglect of what can be done now. Former President George W. Bush often used future technology as an excuse for inaction, touting research on hydrogen fuel-cell “freedom cars” while rejecting proposals to improve the efficiency of today’s vehicles. One energy economist quipped, the freedom car “is really about Bush’s freedom to do nothing about cars today”.
Similarly, longtime climate sceptic Bjorn Lomborg claims that the best, most cost-effective approach isn’t any of the policy proposals on the table in the US Congress or at the Copenhagen conference - for instance, carbon taxes or a regime of cap-and-trade - but rather one of the sunshade technologies that would boost the cooling capacity of clouds by spraying saltwater into the air to stimulate the formation of more cloud droplets.
If Lomborg and his allies in conservative think tanks tout such technofixes as a better “solution” to the climate change, others such as Crutzen and Ralph Cicerone, president of the National Academy of Sciences, see it as an insurance policy in the event of full-blown emergency. They advocate research to distinguish the merely risky geoengineering schemes from the manifestly mad. It is hard to object to a backup plan, especially as the world has not yet halted emissions, much less embarked on the deep reductions that are required.
Insurance, however, often has a perverse effect: The promise that something will be there to bail you out if the worst happens encourages imprudent behaviour. The number of mountain rescues has increased because hikers carry cell phones. The National Flood Insurance Program for people living in coastal communities aimed to discourage development in high-risk areas by providing subsidised insurance if the local government agreed to guide development away from flood-prone areas, but the program instead has increased development in these danger zones. Similarly, geoengineering schemes foster the notion that technology can rescue us from climate hell, if it comes to that, and thereby discourages early, prudent action to head off the worst danger.
The political hazards of deliberate planetary manipulation are as formidable as the moral pitfalls. The technologies that scientists and engineers regard as “insurance” to safeguard the human future may precipitate new kinds of international conflict and the possibility of an arms race in geoengineering technology.