NEXT: Can we “Hack the Planet” to Counter Climate Change?
When Mount Pinatubo in the Philippines erupted in 1991, the enormous quantity of sulfur it spewed into the atmosphere blocked enough of the sun’s rays to drop planet-wide temperatures by half a degree Celsius. Large volcanic eruptions throughout history have had similar climate-cooling effects. Some scientists and engineers have proposed that artificially inducing similar conditions could help relieve the effects of climate change.
There are three chief “solar geoengineering” methods: one such method is called “albedo enhancement,” which means making clouds more reflective such that they reflect more sunlight back into the atmosphere. We could also deploy “space reflectors,” which would block sunlight. David Keith — who is a professor of applied physics and public policy at Harvard as well as executive chairman at Carbon Engineering, a company that is developing tools to extract carbon dioxide from the atmosphere — offers that we could also make use of stratospheric aerosols which would involve injecting the upper atmosphere with particles like sulfuric acid that would reflect sunlight back into space, an artificial volcanic eruption that would cool the planet.
Another set of approaches would involve carbon dioxide removal, otherwise called “carbon geoengineering.” These are techniques that remove carbon dioxide directly from the atmosphere, and include afforestation, a world-wide tree planting effort of such scale that the excess trees remove CO2; biochar, which involves burying charred biomass; and ambient air capture, which would involve building large machines that would “vacuum up” carbon from the atmosphere and then storing it someplace, probably underground.
Even if we were to somehow halt massive greenhouse gas emissions this afternoon, it would still take some time for global temperatures to drop to more manageable levels. Geoengineering projects like these could bring down temperatures much more rapidly.
But it should be made clear that many of the substances that we would be catapulting into the air are pollutants: that we would be in effect addressing climate change by polluting the upper atmosphere. And it is not even clear if any of these methods are technically feasible. Keith also notes that geoengineering projects would require a level of inter-governmental cooperation that seems difficult to fathom today. Other observers worry about creating another bloated Cold War-era big science moonshot, and suggest instead that we think of geoengineering as an Information Age, social-media-fueled, decentralized and nimble endeavor.
Keith is at pains to say that solar geoengineerring alone will not halt climate change, and that we would still need to reduce carbon emissions as part of an overall strategy to reverse the warming of the planet. Therefore, it does little good to think that all of our problems will be solved by this technological fix. Indeed, Keith is quick to point out that the techniques he advocates would also involve significant environmental harm. “Injecting sulfates into the stratosphere,” for instance, “will likely increase the damage to the ozone layer and when the sulfate particles descend into the lower atmosphere they will contribute to air pollution.” And many of the solar geoengineering solutions suggested would not necessarily deal with ocean acidification. While he is confident that solar geoengineering can help reverse climbing global temperatures, at what cost are we as a global society willing to pay for that turn around?
It is a measure of the situation in which we find ourselves that thoughtful scientists and engineers are proposing such radical and potentially risky “planetary hacks” to deal with climate change.
David Staley is president of Columbus Futurists and a professor of history and design at The Ohio State University.
The next Columbus Futurists monthly forum will be Thursday March 24 at 6:30 PM at the Panera Bread community room (875 Bethel Rd.) Our topic for the evening will be “Is there oil in our future?”