Nathan Myhrvold appeared last week on Fareed Zakaria's GPS making a compelling argument for geo-engineering in general, and one scheme in particular. I encourage you all to hear him out.
The arguments against geo-engineering tend to fall into three categories. The first is that we don't know whether geo-engineering will work. The second is that it is harmful to even talk about geo-engineering because it might puncture the political will to reduce carbon emissions. Third and finally, geo-engineering is a bad idea because it might bring about unintended side-effects.
Like most advocates of geo-engineering, I would argue that it should be researched further and deployed in conjunction with emission controls, not replacing them. However, in the interest of a fuller examination of our options, I will note that all three arguments could be made just as convincingly against emission controls.
We certainly don't know that an emission control strategy will work -- politically, at least. The IPCC has said that developed nations should reduce carbon emissions by 25-40% come 2020 in order to have a 'reasonable chance' of averting catastrophic global warming. Many now say these targets are too lax, but the Waxman-Markey bill currently being considered in the Congress wouldn't meet them. The bill would reduce U.S. emissions by 17%, and and even that weak bill has little chance of becoming law. With China determined not to jeopardize its growth strategy with verifiable targets, the odds of a global treaty that might head off global warming have to be counted as tiny.
The second argument is easier to dispense with. As Myhrvold himself argues, blaming geo-engineering for reducing the will for carbon controls is like blaming a bypass surgeon for encouraging his patient's snacking. You might also blame carbon controls for discouraging people from taking geo-engineering seriously.
The final argument is more substantive. Many people instinctively recoil at Myhrvold's proposal to reduce solar radiation by pumping sulfur dioxide into the stratosphere via an 18-mile-long hose suspended by a trail of balloons. How could more pollution cure the effects of pollution? But the reason Myhrvold focused on sulfur dioxide is because a natural experiment of this stratagem has already occurred. When Mount Pinatubo erupted in 1991, 20 million tons of sulfur dioxide were injected into the air, lowering temperatures by half a degree. We know the climactic effects of this chemical, and we know its atmospheric effects as well because our power plants already eject it, albeit at far lower altitudes than Myhrvold is proposing. The overall amount of sulfur dioxide believed to be necessary to tame global warming is about one-twentieth of one percent of the amount ejected today by natural and man-made sources, but by expelling it near the arctic and at high altitudes we would be leveraging this chemical for the maximum of its reflective potential.
Are the risks zero? No. We need to research this idea further. But again, the unintended side effects argument could be made against emission controls too. Not even the most optimistic economists think the transition to a non-fossil-fuel future would be free in terms of GDP growth. Particularly in developing countries, GDP has a high corelation with all kinds of mortality data. Sacrificing growth could cost many, many lives.
If we are to be humble about what we don't know, then we should truly be humble about what we don't know. PBS recently had a valuable piece on the environmental effect of mining rare earth compounds in China. Rare earth, a collection of 17 rare elements in the periodic table, is indispensable for many green technologies from car batteries to wind turbines. At the dawn of the internal combustion engine in the 18th century, we had no idea what effect this technology would have on the environment. Can we say for sure that we know all the risks that renewable energy technologies might pose? These wouldn't be discrete acts like putting a hose into the stratosphere, but a million uncontrolled experiments scattered throughout the globe.
Of course, carbon dioxide has effects other than global warming. It also leads to the acidification of the oceans, for example. That is why geo-engineering cannot replace a saner energy policy, but it has to be at its side, preferably before the 'tipping point' effects such as methane release from permafrost and arctic ice melting take their worst toll. At its most basic, geo-engineering is something humble (and cost-effective) like painting your roof white to reflect more sunlight. More ambitious schemes include seeding oceans with iron to encourage plankton growth (the plankton captures CO2) and using solar-powered devices to create water vapor clouds over seas. The governments of developed countries, including our own, need to explore the safety, effectiveness and viability of these technologies.
Finally, I want to make a purposefully provocative comparison. The right-to-life movement tells us that abortion is murder. If they really think it's murder, shouldn't they be the biggest advocates of education about contraceptives? Usually they aren't, because they often believe that sex out of marriage is a sin too, and that education about contraceptives encourages this sin. Of course, education about contraceptives is not promiscuity. It is not even encouraging promiscuity, and might well include messages intended to discourage it. At its worst, education about contraceptives might be seen as encouraging promiscuity. So let's step back: is seeming like you might be encouraging promiscuity really worse than murder? Even if it were a sin, shouldn't you pick a lesser sin if it will diminish a far greater sin? The truth is that the right-to-life movement wants to use abortion as a trojan horse for its ethos. They say abortion is murder, and I'm sure they believe it, but they aren't willing to let go of their worldview in order to act rationally on their convictions.
I fear the same thing is true for not all but many environmentalists. They say the fate of the planet is in the balance, but if it truly is, shouldn't we be exploring every avenue to solve the problem? In the clip, Fareed Zakaria describes their attitude as Calvinist. I'd say they have developed a sort of secular spirituality. In their view, the only thing that will appease Mother Earth is not another sin, but the properly sanctioned sacrifice.