How to think about solar radiation management

02/24/23 • 66 min

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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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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...

(PDF transcript)

(Active transcript)

Text transcript:

David Roberts

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

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

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

David Roberts

Not super comforting.

Kelly Wanser

Previous Episode

Meet the author of Biden's industrial strategy

In this episode, Brian Deese, outgoing director of the National Economic Council and an influential advisor to President Biden, discusses the opportunities and challenges in Democrats’ new focus on industrial policy.

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David Roberts

Brian Deese has had a remarkable two years. As President Joe Biden’s top economic advisor and director the National Economic Council, he has played a key role in defining and implementing Biden's policy approach.

In April of last year, he delivered some “remarks on a modern American industrial strategy” that laid out a vigorous approach to investing in economic sectors deemed important to national and economic security.

And by all accounts Deese played a pivotal role in seeing the strategy into law, through the Infrastructure Investment and Jobs Act (IIJA), the CHIPS and Science Act, and the Inflation Reduction Act, which together amount to the greatest reinvestment in US infrastructure and manufacturing — and, specifically, clean energy industries — in generations.

The pivot to unapologetic industrial policy is a big change for Democrats. Deese has moved in those circles for a long time — ten years ago he was a young wunderkind advisor to Obama, making The New Republic’s list of “Washington's most powerful, least famous people” — so as he prepares to depart the administration, I was eager to talk with him about what the shift to industrial policy means, why the US needs to onshore key supply chains, and the work ahead for Democrats in implementing their new laws.

All right, then. Brian Deese, welcome to Volts. Thank you so much for coming.

Brian Deese

Oh, I'm really happy to be here.

David Roberts

I had, I'll say, a little banter, maybe a couple of jokes scheduled here for the front end of the pod. But then I looked at my list of questions for you, and we don't have time for any jokes, Brian. We don't have time for any banter.

Brian Deese

Very serious, very quick.

David Roberts

We got to get deadly serious right off the bat here. So let's start here in 2012. Ten years ago, you were the deputy director of the NEC under Obama. And in 2022, ten years later, you were the director of the NEC under Biden. And I'm just curious how things have changed, how America's sort of strategic economic outlook has changed in that ten years. And specifically, I'm curious whether the sort of vigorous investment in industrial policy that we're going to talk about here in a little bit, the kind of stuff that has been going on under Biden, whether you were recommending that to Obama at the time, or whether there's something importantly unique about this present moment.

Brian Deese

Well, look, I think a lot of the world has changed since that period, both in policy and economic terms. If you think back to 2012, we were both right on the back end of a historic and transformational policy accomplishment in the enactment of the Affordable Care Acts, which changed the fabric of our economic and social safety net in important ways right on the front end of that implementation. And at the same time, in a period of very challenging and slow recovery from the Great Recession that was made worse by a failure of policy, a failure of the ability for Congress to overcome Republican opposition at the time, to invest more, to try to help to drive a stronger recovery. You look over those ten years, we live through a period that a number of people have characterized as secular stagnation where our output was constrained and that had a lot of impacts on quality, on labor markets.

And then of course, we lived through this once in a century event of the global pandemic and in many ways historically unprecedented in modern human history. And I think that that helped to bring to the forefront a set of economic challenges that had persisted over that decade and much longer. But we're now really to the floor, partic...

Next Episode

Taking carbon out of the air and putting it into concrete

Under a new partnership, Heirloom Carbon Technologies captures carbon dioxide from the air, then passes it to CarbonCure Technologies, which permanently sequesters it in concrete. In this episode, CEOs Shashank Samala of Heirloom and Robert Niven of CarbonCure give the lowdown on this pioneering carbon removal project.

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David Roberts

Last month saw the announcement of a pioneering project: a company called Heirloom Carbon Technologies will capture carbon dioxide from the ambient air and then hand it off to a company called CarbonCure Technologies, which will inject the CO2 into concrete made by a company called Central Concrete. It will mark the first time ever that carbon from the air is permanently sequestered in concrete.

Heirloom, with runs the US’s only operating direct air capture (DAC) facility, does not use the familiar capture technique that involves giant fans. Instead, it binds carbon to exposed rock and then cooks it out using electric kilns — and then binds more carbon to the rock, in a circular process. It claims the capture is cheaper and more efficient than previous methods.

CarbonCure injects the CO2 into a concrete mixer, where it mineralizes, becoming permanently captured even if the building using the concrete is demolished. In the process, it strengthens the mix, requiring less cement and cutting costs.

Direct air capture (DAC) has faced a great deal of skepticism, and concrete has the reputation as one of the worst carbon offenders, so this project — one of the first that can fairly be called carbon removal — could go a long way toward convincing investors that the former can help the latter change its ways, with a technology that is, at least some day, commercializable.

I talked with Heirloom CEO Shashank Samala and CarbonCure CEO Robert Niven about their respective processes, how they work together, and what the project says about the future of carbon removal.

All right, Shashank Samala, CEO of Heirloom Carbon Technologies, and Robert Niven, CEO of CarbonCure. Welcome to Volts. Thank you guys for coming.

Robert Niven

Thanks very much for having us.

David Roberts

This is really a nifty project you guys are working on together. It's two separate pieces that normally I would probably do a pod on each. So we're going to have to, or at least I'm going to have to be less wordy than normal to squeeze it all in in 1 hour. I want to talk about both halves of it. So let's start with Shashank. The first half of this process is Heirloom’s process of removing carbon from the air. Can you just explain quickly how that process works, what it looks like?

Shashank Samala

Sure. So, Heirloom, if you're not aware of who we are, our goal is to basically remove a billion tons of CO2 from the atmosphere annually by 2035. And our whole goal is to help reverse climate change. And the way we do that is through a process called limestone looping. Essentially what that means is we use a rock that is very abundant in nature, limestone, that has a natural propensity to pull carbon from the air. What we do is we basically give superpowers to limestone to pull a lot more carbon than it otherwise would naturally.

So how it works is we start with limestone, we put that into a kiln, we heat it up, and we pull out the CO2 that's already sequestered in the limestone, which makes the leftover lime highly thirsty for CO2. So we take advantage of that natural property by laying it out on trays. Think about baking trays. I lay them out on trays, and then we vertically stack those trays, very tall, and the air brings in the CO2. And the the lime sitting on the tray acts as a sponge, pulls up the CO2 molecules. From there, it becomes limestone again after it pulls it up. And we do that in about three days.

Naturally, it would take many months to pull carbon from the air. We did that in three days u...