The scientists who study solar geoengineering don’t want anyone to try it. But climate inaction is making it more likely.
By Bill McKibben, Nov 22nd 2022
If we decide to “solar geoengineer” the Earth—to spray highly reflective particles of a material, such as sulfur, into the stratosphere in order to deflect sunlight and so cool the planet—it will be the second most expansive project that humans have ever undertaken.(The first, obviously, is the ongoing emission of carbon and other heat-trapping gases into the atmosphere.) The idea behind solar geoengineering is essentially to mimic what happens when volcanoes push particles into the atmosphere; a large eruption, such as that of Mt. Pinatubo, in the Philippines, in 1992, can measurably cool the world for a year or two. This scheme, not surprisingly, has few public advocates, and even among those who want to see it studied the inference has been that it would not actually be implemented for decades. “I’m not saying they’ll do it tomorrow,” Dan Schrag, the director of the Harvard University Center for the Environment, who serves on the advisory board of a geoengineering-research project based at the university, told my colleague Elizabeth Kolbert for “Under a White Sky,” her excellent book on technical efforts to repair environmental damage, published last year. “I feel like we might have thirty years,” he said. It’s a number he repeated to me when we met in Cambridge this summer.
Others, around the world, however, are working to speed up that timeline. There are at least three initiatives under way that are studying the potential implementation of solar-radiation management, or S.R.M., as it is sometimes called: a commission under the auspices of the Paris Peace Forum, composed of fifteen current and former global leaders and some environmental and governance experts, that is exploring “policy options” to combat climate change and how these policies might be monitored; a Carnegie Council initiative of how the United Nations might govern geoengineering; and Degrees Initiative, an academic effort based in the United Kingdom and funded by a collection of foundations, that in turn funds research on the effects of such a scheme across the developing world. The result of these initiatives, if not the goal, may be to normalize the idea of geoengineering. It is being taken seriously because of something else that’s speeding up: the horrors that come with an overheating world and now regularly threaten its most densely populated places.