How to think about solar radiation management

Even if greenhouse gas emissions halted entirely right now, we would continue to feel climate change effects for decades due to existing carbon dioxide in the atmosphere — and warming could accelerate, as we reduce the aerosol pollution that happens to be acting as a partial shield. In this episode, Kelly Wanser of nonprofit SilverLining makes the pitch for solar radiation management, the practice of adding our own shielding particles to the atmosphere to buy us some time while we step up our greenhouse gas reductions.

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Text transcript:

David Roberts

One of the more uncomfortable truths about climate change is that temperatures are going to rise for the next 30 to 40 years no matter what we do, just based on carbon dioxide already in the atmosphere and the reduction of aerosol pollutants that are now shielding us from some of the worst of it. That's going to bring about potentially devastating changes that we do not yet well understand and are not prepared for.

How can that short-term risk be mitigated? One proposal is to add particles to the atmosphere that would do on purpose what our aerosol pollution has been doing by accident: shield us from some of the rising heat. No one credible who advocates for solar radiation management (SRM) believes that it is a substitute for reducing greenhouse gas emissions. Instead, it would be a way to buy a little more time to reach zero carbon.

My guest today, Kelly Wanser, is the head of a non-profit organization called SilverLining that advocates for research and policy around near-term climate risks and direct climate interventions like SRM that can address them.

I've long been curious about — and wary of — solar radiation management, so I was eager to talk to Wanser about the case for SRM, what we know and don't know about it, and what we need to research.

Okay then. Kelly Wanser of SilverLining, welcome to Volts. Thank you so much for coming.

Kelly Wanser

Thank you very much, David. I am a fan and it's a pleasure to be here.

David Roberts

Awesome. Well, I have wanted to do a pod on this subject forever. I'm going to try to be focused, but I sort of have questions that are all over the place, so let's just jump right in. The way I'm approaching this is, I think, to average people off the street, and maybe I even include myself in this. The idea of reaching up into the atmosphere and fiddling with it directly, thinking that we can dial in the temperature we want, strikes me as crazy. And I think that's probably a lot of people's intuitive response. Obviously, you have thought your way past that, going so far as to found an organization designed to advocate for this stuff.

So maybe just tell us a little, to begin with, your personal background and how you came to advocacy for geoengineering, which is not a super crowded field.

Kelly Wanser

I'll say first that you're actually not in the business of advocacy for geoengineering and it will give you some context for how I came to be doing what I do.

David Roberts

Sure.

Kelly Wanser

Really it was about — I was working in the technology sector in an area called IT infrastructure, and that's the sort of plumbing of data in the Internet and was looking at problems like how you keep networks operating. And I started to read about climate change, and I was very curious about the symptoms that we were starting to see in the climate system and where the risk really was. And I started to get to know various senior climate scientists in the Bay Area and other places, and I asked them the question like you might ask, how would you characterize the risk of runaway climate change in our lifetime? And this is maybe twelve years ago.

And they said, "Well, it's in the single digits, but not the low single digits."

David Roberts

Not super comforting.

Kelly Wanser

Yeah, I mean, my original degree was economics, so I thought, well, if you had those odds of winning the lottery, you'd be out buying tickets. If you had those odds of cancer, you'd be getting treatment. So that seemed like a really high risk to be exposed to. And then they told me about another feature of what was happening in that carbon dioxide stays in the atmosphere for a long time, keeping things w...