In the debate surrounding solutions to climate change, we’ve heard of everything from space-based power stations to wrapping Greenland in reflective blankets. One proposal of global proportions has become more popular in recent years. Known as climate engineering, it consists of altering the climate, only this time by design. The most promising technique involves injecting large amounts of reflective aerosols into the stratosphere to reduce the amount of solar radiation hitting the Earth’s surface. The concept is fairly straightforward: Since the atmosphere’s elevated concentrations of greenhouse gases make it more effective at heating the planet with the sun’s rays, this plan focuses on ensuring that less solar radiation hits the Earth altogether. This is essentially induced global dimming – the blocking of the sun.
The concept of climate engineering is in some ways deeply appealing. The idea of engineering a way for us to avoid any substantial shifts in our lifestyles speaks to our natural aversion to change. We are also preoccupied by a fascination with technologies that empower us to control nature (we’d rather build levies to hold back the sea than site our communities on higher ground), and a controlled alteration to the climate is on certain levels the ultimate achievement. We like to build our way out of problems and, quite frankly, we’re pretty good at it.
But rather than being the miraculous technical feat we hoped it would be, climate engineering is a reckless attempt to put off the tough choices we must ultimately make. While the sulfate aerosols being considered are chemically identical to those released by volcanic eruptions, the trouble is not the particles’ properties but rather how they are introduced into the atmosphere. The fact that our injections would be inherently artificial is cause for pause. All too often we have been reminded that our understanding of natural systems is far from complete. Intervening (yet again) in one as large and complex as the climate system will surely result in unintended consequences. For a smaller-scale reminder, just look at the story of garlic mustard in the Eastern US. Originally introduced to combat soil erosion, the plant has become enormously widespread. Its pervasiveness destroys forest understory, poisons insects, and threatens the surrounding biodiversity. Similar examples abound, and the lesson is clear: interfering with complex natural system, the intricacies of which we seldom fully understand, is risky, despite good intentions.
Another shortcoming stems from climate engineering’s limited scope. While sulfate aerosols can reflect the sun’s rays back into space, they do nothing to address ocean acidification, a major impact of climate change. Because ocean acidity is directly related to atmospheric concentrations of CO2 and has nothing to do with surface temperature, any solution that ignores greenhouse gas emissions would be wildly inadequate.
One popular defense of climate engineering is the speed with which it can take effect. Experts are certain that releasing the particles would begin reducing the rate of warming very soon. It turns out that their effects are also relatively short-lived, so a round of injections wouldn’t have a long-term impact. While these facts are undisputed, the broader argument they support is that the technique should be employed to slow climate change while we develop sustainable ways to reduce greenhouse gas emissions. The overwhelming flaw in this approach is that it ignores our predisposition for complacency. A short-term extension is a nice idea, but we’re already taking long enough to develop solutions under increasing agreement about the urgency of climate change. Are we really supposed to believe that taking the pressure off will help? Many experts fear that “buying more time” will simply reduce the incentive to get serious about addressing emissions. And as a bonus, there’s concern that this strategy may impact local weather systems unpredictably.
So the issue with climate engineering is not that the technique won’t work – given enough R&D, there’s a good chance it would. But will it work as planned? Will it slow the rate of warming without changing the weather or acting as a shield for the status quo? Some may say that the continued hope of addressing climate change without climate engineering is wishful thinking. But the real danger lies in distractions such as these, which, although well intended, stand to cripple the pursuit of real solutions.
The Verdict: Climate engineering is an appealing concept that may be technically feasible. Folded into the promises of short-term benefits and time-buying crisis aversion, however, is a concerning set of profound and poorly understood risks. Climate change is an urgent challenge that requires us to think big and pursue our best ideas. While climate engineering is certainly a big idea, it risks more than it offers in an honest pursuit of a more sustainable future.