By Michael T. Burr

The London-based Institute of Mechanical Engineers (IME) published a thought-provoking report in August examining the role of geoengineering strategies for dealing with climate change. The report is interesting partly because of the technologies it examines, but mostly because of the policy argument it raises.

The report focuses primarily on three approaches, namely:

- CO2 scrubbing artificial “trees,” containing sorbents that would require subsequent burial;

- Algae-growth strips, attached to buildings and later harvested for biofuel production; and

- Reflective roofing, intended to direct solar radiation back into space and reduce AC demand.

Although these approaches seem novel and interesting, I’m not sure they really comprise geoengineering. The National Academy of Sciences defines geo-engineering as “large-scale engineering of our environment in order to combat or counteract the effects of changes in atmospheric chemistry.” Examples include seeding the stratosphere with reflective sulfur aerosols, or stimulating phytoplankton blooms by fertilizing ocean shallows with iron. By contrast, the hands-on, site-specific technologies discussed in the IME report would face a very steep growth curve before they could resemble “large-scale engineering.”

Quibbling aside, however, the IME report merits attention, if only because it makes an important point that’s been mostly ignored in the climate policy debate. In short, most discussions seem to position geoengineering as a “Plan B” approach to addressing climate change. In other words, if Plan A fails, and greenhouse gas (GHG) reduction and mitigation fall short of what’s necessary to avoid a climate catastrophe, then we’ll default to Plan B — direct intervention in the global climate, vis-à-vis geoengineering.

The IME report suggests that if we wait for GHG policies to fail before putting R&D resources into geoengineering, then it might be too late for geoengineering to work — or to be more precise, reining-in a runaway climate might require desperate geoengineering measures, incurring higher costs and yielding more damaging side-effects for the environment than we’d get with more moderate approaches. Instead, the report argues, policy makers should treat Plans A and B as complementary rather than exclusive approaches, and should consider geoengineering as part of an integrated strategy — a strategy that notably includes adapting to the inevitable climate change that already is happening and almost certainly will continue, to some degree, no matter what we do.

“Two decades of failed global mitigation efforts should be a wake-up call,” the report states. “It could be geo-engineering that provides the global community with those extra years to introduce effective mitigation and adaptation strategies, and, in the long term, remove some of the existing CO2 from the atmosphere. As such, Plan B needs to be upgraded to become a fully integrated part of a comprehensive three-point approach embracing mitigation, adaptation and geo-engineering.”

In other words, if we’re re-tooling for a more sustainable future, then we should make sure we’re using all the tools at our disposal — not just the ones that adapt our economy, but also the ones that adapt the climate itself. In the long term this might turn out to be the inevitable strategy, given the century we’ve spent gasifying the planet’s fossilized carbon. But that strategy will be cheaper and less damaging if we accept and pursue geoengineering earlier, rather than later in the process. -MTB