According to the International Energy Agency, we’ve already sent enough carbon into the atmosphere to change the climate, and we’re quickly running out of time to keep emissions at a safe level. That’s why some climate scientists are giving up on the political battles over cap and trade and turning to geoengineering–radical, large scale plans to counter the effects of global warming, like pulling carbon back out of the air or putting giant mirrors in space.
Sound crazy? Craziness is a hallmark of geoengineering ideas. But people are starting to take them seriously.
In late 2010, the aerospace company Aurora Flight Sciences, working with the University of Calgary and supported by funding from Bill Gates, produced a major study (PDF) on the feasibility of cooling the planet by simulating the effects of a volcano. It may be the first serious look at the feasibility of a large-scale geoengineering project, but has only recently attracted the media’s attention.
The authors looked at what it would take to get millions of tons of sulfur dioxide 100,000 feet into the atmosphere, creating sulfate particles to shade the earth from the sun. They studied several different approaches in painstaking detail.
Rocket-based systems, they concluded, would be too expensive–more than $1 trillion per year. The authors also considered using enormous Mark 7 naval guns, but delivering enough sulfur dioxide would require 70 million shots per year. Total cost: $20 to $100 billion per year.
The three most promising ways of getting that much sulfur dioxide that high in the atmosphere were blimps, floating platforms, and specially built airplanes. All three would be relatively cost-effective–somewhere in the single billions per year–but the authors ultimately recommend planes as the best choice. The uncertainties involved in developing new blimps or a completely novel high-altitude platform make them riskier strategies.
Simulating a volcano, the authors conclude, “is feasible from an engineering standpoint and costs are comparable to quantities spent regularly on large engineering projects or aerospace operations.” Let’s hope it doesn’t come to that.