One problem with geoengineering: Once you start, you can’t really stop
Many of the world’s nations show few signs of cutting their greenhouse gas emissions anytime soon. That’s why, in recent years, more and more climate scientists have been pondering the concept of “geoengineering” as a way to slow the pace of global warming.
When Mount Pinatubo erupted in the Philippines in 1991, it cooled the planet nearly 1 degree Fahrenheit. Geoengineering would work a lot like that. (Arlan N.Aeg/AFP/Getty Images)
One popular idea involves spraying reflective particles into the atmosphere to deflect a small portion of Earth’s sunlight. Harvard scientist David Keith discussed the pros and cons of the idea at length in a recent interview.
Pros: It’s cheap, easy, and could likely avert some of the worst impacts of global warming, like sea-level rise. Cons: It could have lots of unpredictable side effects, like mucking up global rainfall patterns. It’s difficult to coordinate. And geoengineering does nothing to address other severe climate impacts, like ocean acidification.
But there’s one other concern we didn’t really touch on in that interview: Once the world starts geoengineering, we can’t really ever stop — especially if everyone keeps pumping carbon-dioxide into the atmosphere at the same time. Why? Because as soon as we quit spraying those reflective particles into the atmosphere, the Earth will heat up very, very, very rapidly. And sudden climate change is even worse than the kind we already know about.
