Of all the responses to climate change that involve actually doing something to stop it, the idea of geoengineering is the most radical–fixing the climate by tinkering with Earth’s physical systems, rather than lowering the emissions that cause warming. Examples of these tactics include dispersing particles in Earth’s upper atmosphere that would reflect more sunlight or even seeding the oceans with iron so they’ll absorb more CO2.
Even pursuing field research into geoengineering has been incredibly controversial. A major fear is that the idea gives nations an easy escape clause–another excuse not to do the hard, necessary work of lowering greenhouse gas emissions today. And at least some proposals could have massive unintended or negative consequences for the planet; spraying aerosols into the upper atmosphere, for example, could significantly affect rainfall patterns around the world on its own. Other options, like capturing carbon and storing it underground, are simply very expensive and a far way off today.
This week, the National Academy of Sciences issued two major reports on the topic from a panel of the nation’s top experts. The report grouped geoengineering solutions into two categories. The first–methods that reflect more of the Sun’s energy away from Earth–they called “irrational and irresponsible” to deploy, especially without also lowering emissions or removing emissions from the air at the same time. They also highlighted the many risks to changing Earth’s reflectivity, which would be cheap and easy to do but could change weather patterns globally or even be used as a “weapon” by a single nation.
Yet the panel couldn’t dismiss research around the idea entirely, especially because global warming on its current path could cause disasters around the world decades from now.
“Although riskier ideas to lessen the amount of energy absorbed from the sun should not be considered for deployment, they should be studied so that we can provide answers if someday these ideas begin to be considered in attempts to avert catastrophe,” wrote National Academy of Sciences President Ralph J. Cicerone in a press release.
The panel views the second class of the methods, carbon capture and removal, differently. Some are low-risk and easy to do now, such as planting more forests around the world to soak up carbon. Others, like directly capturing CO2 from the air through various technologies, aren’t ready yet. Another option–seeding the oceans with iron–carries risks that outweigh the benefits right now, the academy says. Overall, the panel recommends more investment in R&D to look at carbon capture options that could make sense on a global scale, including field experiments.
David Keith, a geoengineering researcher who was not on the panel, told the New York Times that he hoped the reports would “break the logjam” in research and “give program managers the confidence they need to begin funding.” The planet might one day be grateful they did.