The inside scoop on solar geoengineering

That’s how I’ve felt watching the news about solar geoengineering unfold over the past several months. Thanks to a few big news events, efforts to cool down the planet by reflecting some sunlight back into space are suddenly a huge part of the public conversation.

But some people have been watching this show for years. And lucky for me, I get to work with one of them: James Temple, senior editor for energy here at MIT Technology Review. James has been following the field of geoengineering for nearly a decade, and he just published an in-depth essay about what all these recent developments could mean for the future of the climate. So for the newsletter this week, let’s take a look at the world of solar geoengineering. 

What is solar geoengineering, anyway? 

Geoengineering is an umbrella term that covers a wide range of efforts to alter the Earth, usually in some way related climate change. Propping up a melting glacier, for example, could be considered a form of geoengineering. 

Solar geoengineering, as you might guess from the name, involves sunlight. Reflecting some of the sun’s radiation back into space could help cool the planet, counteracting the warming caused by greenhouse-gas emissions. 

The solar geoengineering approach that’s gained the most attention involves using aircraft like balloons or planes to release gases or small particles into the atmosphere that would reflect sunlight, easing warming. Other potential paths include brightening clouds over oceans or even launching elaborate sunshades. By the way, this is all mostly theoretical so far, since nobody can really agree whether we should even be studying solar geoengineering, much less doing it. 

So what’s all the buzz about? 

Some academic groups have been trying to research solar geoengineering for years. But these efforts have hit roadblock after roadblock, and scientists are facing public opposition to even small-scale experiments designed to better understand how efforts to reflect sunlight might work. Caution here is understandable: tweaking the climate at a big enough scale can have huge effects, and some are concerned that even relatively modest actions could have unintended consequences.