[ed. It makes my head spin just to think about all the treaty and regulatory approvals needed to secure something like this, not to mention the politics involved in achieving a global buy-in. The sad fact is nothing will be done to ameliorate climate change until we reach some hysterical crisis/tipping point, and by then even geoengineering may be too little, too late.]
One of the two main categories of geoengineering is solar radiation management, or SRM. (The other is the direct removal of carbon dioxide from the atmosphere.) The idea is to mimic what volcanos do naturally, by putting aerosol particles into the stratosphere on a massive scale. For example, when Mount Pinatubo erupted (image, above) in 1991, the cloud that encircled the planet caused an overall cooling of about half a degree. An argument has been raging for years now about the wisdom of creating our own version of a volcanic eruption: Can it be done? Should it be done? What are the risks? What are the benefits? A few countries and research groups have tried to start demonstration projects; even these proof-of-concept exercises have garnered significant backlash from the scientific community as well as the public at large.
Most scientists would agree, though, that geoengineering ideas are at least worth looking into. And one of the primary questions is whether we can afford to do it. A new study published in the journal Environmental Research Letters has done athorough cost analysis of the main techniques for SRM—importantly, this is not a cost-benefit analysis, where risks and benefits are included, but simply a look at the costs of putting enough aerosols into the atmosphere. What they found is either encouraging or terrifying, depending on one's feelings about geoengineering: it is, in the grand scheme of things, very, very cheap.
The authors, Justin McClellan, David Keith, and Jay Apt, found six main schemes for SRM:
by Dale Levitan, IEEE Spectrum | Read more:
Image via D Harlow/USGS
