An Engineering Experiment to Cool the Earth (2024)

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From “The New York Times,” I’m Katrin Bennhold. This is “The Daily.”

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After failing for decades to cut carbon emissions enough to stop the planet from dangerously overheating, scientists are increasingly looking at backup measures, some that would fight the warming by intervening in the climate itself. Today, my colleague Christopher Flavelle on the efforts to engineer our way out of the climate crisis.

It’s Friday, April 5.

So, Chris, you’ve been covering climate change for a while, but recently you’ve been focused on a very special project. Tell us about this.

Yeah, two things have been happening in climate change recently that are really important. Number one, records have been falling at alarming rates. Last year was, again, the hottest year on record. Much the world surpassed the important threshold of 1.5 degree Celsius above pre-industrial levels. So the world is getting warmer at an alarming rate.

At the same time, emissions aren’t falling. The message of the last generation has been, we need to cut emissions really to almost zero by the end of this century. And in fact, the reverse is happening. Emissions are continuing to rise.

At the same time, the number and characteristics of weather disasters have become really alarming. So the effects of that warming have become really clear. And it’s clear that the world is struggling to adapt to those effects.

So the other thing that’s happening at a high level is there’s more research and more consideration of OK, what if we can’t cut emissions fast enough? What if we’re going to have this really severe degree of warming? Can we do something else, maybe temporarily, to buffer those effects? And that’s led to this question of, what kinds of changes can we make deliberately to the atmosphere, to the environment that will maybe produce some sort of artificial cooling in the meantime?

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So earlier this week I was able to watch, as scientists did, the first outdoor tests in the US on a technology that will aim to do just that. It’s called marine cloud brightening.

So what is this idea of brightening the clouds? Where did it originally come from?

So everyone I talked to pointed back to one really important moment in 1990 when a British physicist named John Latham was taking a hike in Wales with his young son. And they were looking out at the clouds over the Irish Sea.

And as Dr. Latham later told it, his son asked him, “Hey, why are clouds bright?” And Dr. Latham said, “Well, because they reflect sun right back in the sky.” And his son said, “So they’re like soggy mirrors.”

And Dr. Latham went on to write a letter in 1990 that was published in the Journal Nature, saying, you know what, if we can deliberately manipulate these clouds, maybe we can make them more reflective and actually counteract the effects of global warming. That was the inception point for this idea, and it led to decades of research culminating in this week’s test.

So the idea is if you can make clouds more reflective, you can reflect more of the sun’s heat back into space. So it won’t get trapped in the Earth’s atmosphere in the first place.

Exactly. That’s what they’re trying to do.

That’s a very simple, and at the same time, a very powerful idea. I love actually that they were hiking in Wales. That’s where I am right now, and we sure have a lot of clouds here, rain clouds. But tell me more about what you saw at the testing site.

So this Tuesday, a little after 7:00 in the morning, I pulled up in a parking lot on a dock at the edge of Alameda.

And I made my way up one of the massive gangplanks and came in to find a cluster of some of the top atmospheric scientists in the world.

Looking really excited. And they accompanied me out to the flight deck —

Which was a bit like a party. They’d set up a little table on the side with some coffee and some sandwiches, and people were chatting and saying hi to each other. And I asked them why they were excited.

And they said this was actually a huge day in their research.

Wow, and tell me about what exactly they were so excited about and what they were doing on the ship.

Yeah, the thing everyone was excited about was this machine set up at the far end of the flight deck of this aircraft carrier. It’s blue. It’s shiny. It looks a bit like a snow maker or maybe like a spotlight.

This machine is a sprayer. What it does is it sprays really, really, really small aerosol particles, in this case, smashed up sea salts, a long distance at just the right size and just the right volume. Because in theory, at some point, you could use this machine to change the size and number of the droplets in the clouds. You can make them brighter conceptually it’s possible. The question is, technologically, can we do it?

And so the goal with this test was they spent years building this sprayer that can use really high pressured air to smash salt particles into super small bits, about 1,700th the size of a human hair.

Wow.

What they didn’t know, until this week, and they’re trying to find out right now, once you spray it, do those aerosols that are so finely tuned stay that size? In theory, they should.

What they don’t know is, things like wind and humidity and temperature could potentially cause them to coagulate, to regroup, which would throw the whole thing off. If the aerosols you’re shooting into clouds are too big, you can backfire the whole purpose. You can wreck what you’re trying to do because you make clouds less reflective, not more reflective.

So the whole goal of the experiment is, OK, can they make the spray just so, so that even in outdoor conditions, the aerosols that are so finely sized remain the size you want them to be. And that’s what they’re trying to find out.

And you watched the actual test of this. What did you see? What happened?

So operating the sprayer is not straightforward.

There was somebody crouched on the control deck, the panel of instruments at the side of the sprayer. So I went over and tried to sit next to him and watch him as he turned a series of knobs and careful sequence.

And after a series of tests to make sure the valves were clear —

— finally the moment came, and he got an all clear over his walkie-talkie. And he turned on the water —

— and the air.

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We all had ear protectors. And even with the ear protectors, it was really loud. And then you can almost feel the spray bursting out of this machine and watch it travel really hundreds of feet down the deck of the aircraft carrier.

My first signal that things have gone well was I looked up when the spraying machine was turned off and saw some scientists high-fiving down the deck.

And everyone seemed really excited that this thing they’d worked on for years was finally happening in this really important outdoor test.

OK, so it sounds like this test was a success.

Yeah, they stressed that they need a lot of time to really go over the results. They’ll be doing this test again and again in different weather conditions. But the initial reaction seemed positive. They seemed to think that the numbers they were getting were what they were hoping to see.

And so now the goal is, can they maintain the right size aerosols even in different conditions down the deck of this aircraft carrier? That’ll give them some confidence that if they decided one day to try and do this on the open ocean to actually brighten clouds, they’d have the ability to do it.

So, Chris, if all of this works, how and when do these researchers anticipate that this would actually be used?

Well, here’s a great example. In the month of February, a version of this testing was also happening in Australia, off the Coast of Australia, where researchers were testing whether marine cloud brightening could be used to cool the ocean just a little bit around the Great Barrier Reef.

Really high ocean temperatures are causing bleaching of that coral reef. The idea was, could they use marine cloud brightening to save some of those reefs from dying? And that’s probably a good idea of the fairly localized situation, where you could, in theory if you do it right, have a fairly quick degree of cooling that could maybe try to avert or mitigate something pretty acute like a heat wave or a stretch of warm weather that would kill coral. But the science is probably too new at this point to talk about the right situations to use it. Those conversations are all down the road as researchers look at these and other ideas for what they could do if things get really bad.

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We’ll be right back.

So, Chris, when I think about solutions to climate change, it usually involves these very hard things we need to do, like, change the way we live, the way we drive, what we eat. We need these international treaties. We need carbon taxes regulation. There’s lots of hard stuff, and we haven’t gotten that far.

But here you’ve just told me about this technology that, if it ends up working, could actually help cool the planet without anyone needing to do any of these hard things. It sounds great.

It does sound great. Now, we’ve got to say, first of all that whenever anybody working on this stuff talks about it, the first thing they say is this is not an alternative to reducing emissions. This is looking for ways to buy time as we try to cut emissions. There’s no way to really deal with climate change that doesn’t entail burning less fossil fuel and quickly.

But yes, in addition to brightening clouds, there’s other ways to try to bounce more sunlight back into space and other ideas. My colleague David Gelles wrote the first piece in our series looking the idea of removing carbon dioxide directly from the air, reversing our past emissions.

Other ideas include finding ways to suck up more of the CO2 in the oceans. There’s even ideas that my colleague Cara Buckley covered of could we build a sort of a giant parasol way out in space that would reflect or scatter more of the sunlight and prevent some of that sunlight from even reaching the Earth in the first place?

So there’s a huge number of ideas that until very recently seemed just so bizarre and/or so expensive and/or so dangerous that they were hardly worth pursuing seriously. And what’s changed really quickly in the last really year or two is all of a sudden those ideas have switched from being too wild to spend much time on to being so important because the situation is so dire that we can’t not look at them. And that’s the pivot that my team has been trying to cover.

And what characterizes all these initiatives is that rather than reducing our own emissions, we’re now trying to intervene in the climate in a proactive way, engineering the climate in a way.

Yes, and you hear the phrase geoengineering to describe these ideas collectively. And what people who research this will stress is, we’re already geoengineering. For more than a century, we’ve been geoengineering in the sense of putting climate changing pollution into the atmosphere that’s caused the planet to change by trapping more heat in the atmosphere. So the question is, do we want to deliberately geoengineer in a way that will ease that pressure rather than just making it worse?

Of course, there some controversy attached to this. And there are some pretty valid concerns about what the consequences might be if we keep on pursuing these ideas.

And why are they controversial?

Well, the first concern that you hear is this idea of moral hazard, that if people come to think that there are ways of addressing climate change that don’t require them to change their lifestyle or sacrifice conveniences or change the kinds of cars they drive or how their power is generated that they will lose interest in those tough changes. And the momentum, such as it is, towards cutting emissions will fade even more. But we don’t know yet whether politicians or governments or companies or just people will misuse these ideas to try to shirk the harder work of reducing the amount of greenhouse gases we emit.

Another really important argument you hear is, OK, side effects. Do we really know what would happen if we tried these things? Marine cloud brightening is one of those situations where there are known unknowns and unknown unknowns, as they say.

The known unknowns are, well, what would happen to things like ocean circulation? What would happen to precipitation? What would happen to the effect on the amount of energy reaching the ocean? What would happen to the fisheries industry? We don’t really know, and researchers are trying to find out, what those effects might be.

Then there are the unknown unknowns. If you start deliberately changing the cloud system, well, what else might happen that we haven’t anticipated? Do you move the location of where rainfall happens? Do you perhaps upset the monsoon cycle in India? Do you change the ability to grow food in parts of the world?

So if you do this at a bigger scale, the consequences of those potential side effects get more and more severe. And I talked to environmentalists who said that’s a real concern. You just can’t model those risks. And you, to a degree, by pursuing this, have to accept that risk is real and almost roll the dice.

And I guess much like climate change, where you have a group of countries that is most responsible for CO2 emissions that have caused the global warming and then a whole other group of countries that are probably suffering the worst consequences, even though they haven’t contributed to those emissions nearly as much, you might see a situation where this kind of interference with the climate at the initiative of some countries, presumably the wealthy countries that have that technology, would then have unintended consequences in countries that have no control over this. So that’s tricky.

That’s right. And that takes us to a third category of concerns, which is, OK, let’s assume that things are bad enough, that collectively societies want to take those risks of those side effects. Well, then who chooses, who decides when we get to that point? Is there even a mechanism that would allow you to get informed consent from everybody who’d be affected?

And if these would affect everybody, it’s hard to imagine how you would build a governance mechanism that would allow you to say, before we push the button, are we sure everybody is OK with this? The only counter to all of these concerns is compared to what? And this is the point that researchers make.

OK, this is dangerous. OK, it presents challenges, but compared to what? Their point is, don’t compare it to a situation where everything’s fine. Compare it to a situation we’re actually in, where the trajectory of global warming is so serious and isn’t looking like it’ll get better any time soon. Well, compared to those risks, how do these risks compare?

And the question is, would you rather have a world of basically uncontrolled warming? And we have an idea of what that brings, wildfires and drought and sea level rise and storms and diseases. Is that better than some of these more perhaps controlled risks associated with deliberately tinkering with the environment?

So it’s almost like pick your poison. What sort of threats do you want to embrace? And that’s the overwhelming dilemma that we face with this technology.

In a way, what it makes me think, is that these crazy initiatives that we’ve been hearing about from you are yes, they’re testament to our failure in a way to combat climate change so far, because they’re such a last resort, really, such as an act of desperation. But at the same time, it seems like this urgency has actually unleashed a lot of energy and money to tackle the problem.

Yeah, and there’s good news in this. The good news is, the research we’re talking about demonstrates the really amazing capacity of scientists to come up with new ideas, develop new technologies, test them quickly, and at least build some options.

So if there’s any rays of hope around climate change, it’s that humanity’s capacity to innovate and find new ideas is almost endless. So the question is not, are we pursuing the wrong research ideas? The question is, can we find good ideas fast enough to avert the really serious consequences of climate change that we’re already facing?

Chris, I just remember that scientist we heard in the tape from your visit. And she was so excited. And she said that she was really optimistic. I wonder, how are you feeling?

I think the frustration that you’ll hear among climate reporters, and I’m in this group, is that most people seem not to appreciate the severity of the situation that we’re in. There seems to be a view that we’re dealing with this. People are buying electric cars, and we’re getting more solar power and wind power. And things are going the right way, and this will be OK.

Things are not going the right way. Not only are we on the wrong trajectory in terms of emissions, we are so far away from being on the right trajectory for emissions that it’s hard to imagine us cutting emissions globally at a rate anywhere near fast enough to avoid almost unbearable consequences of global warming. So that’s the downside.

[MUSIC PLAYING] Here’s the good news, though. I do think, and this again I think is a view among other climate reporters, the capacity of scientists and of companies to change track and to find new products and apply new ideas is really impressive. It just doesn’t feel like there’s a connection yet between the urgency of the situation and the way people and companies and governments are responding.

And so I guess if the question is, how I feel about this? I am constantly amazed at the ingenuity of the researchers I come across in my job every day. What I don’t yet know about is whether or not society will move fast enough to adopt and apply those ideas before the conditions that we face from climate change become almost unbearable.

Well, Chris, on this cautiously optimistic note, thank you very much.

Thank you.

We’ll be right back.

Here’s what else you need to know today. In a tense phone call with Israel’s leader Benjamin Netanyahu on Thursday, President Biden called the airstrikes that killed seven aid workers this week unacceptable and threatened to condition future support for Israel on how it addresses concerns about civilian casualties and the humanitarian crisis in Gaza. It was the first time that Biden explicitly sought to leverage American aid to influence Israel’s conduct of the war against Hamas. But the White House stopped short of saying directly that the president would halt arms supplies or impose conditions on their use as some fellow Democrats have urged him to do.

And a centrist group called No Labels has abandoned its plans to run a presidential ticket in this year’s election after failing to recruit a candidate. The group, which last year said it raised $60 million, had planned to put forward what it called a bipartisan unity ticket in the event of a rematch between President Biden and former President Trump but in recent months suffered a string of rejections from prominent Republicans and Democrats who declined to run on its ticket.

Today’s episode was produced by Michael Simon Johnson, Eric Krupke, Luke Vander Ploeg and Rachelle Bonja. It was edited by Patricia Willens, contains original music by Rowan Niemisto, Elisheba Ittoop, and Marion Lozano, and was engineered by Chris Wood. Our theme music is by Jim Brunberg and Ben Landsverk of Wonderly.

“The Daily” is made by Rachel Quester, Lynsea Garrison, Clare Toeniskoetter, Paige Cowett, Michael Simon Johnson, Brad Fisher, Chris Wood, Jessica Cheung, Stella Tan, Alexandra Leigh Yang, Lisa Chow, Eric Krupke, Marc Georges, Luke Vander Ploeg, MJ Davis Lin, Dan Powell, Sydney Harper, Michael Benoist, Liz O. Baylen, Asthaa Chaturvedi, Rachelle Bonja, Diana Nguyen, Marion Lozano, Corey Schroeppel, Rob Szypko, Elisheba Ittoop, Mooj Zadie, Patricia Willens, Rowan Niemisto, Jody Becker, Rikki Novetsky, Nina Feldman, Will Reid, Carlos Prieto, Ben Calhoun, Susan Lee, Lexie Diao, Mary Wilson, Alex Stern, Dan Farrell, Sophia Lanman, Shannon Lin, Diane Wong, Devon Taylor, Alyssa Moxley, Summer Thomad, Olivia Natt, Daniel Ramirez, and Brendan Klinkenberg.

Special thanks to Lisa Tobin, Sam Dolnick, Paula Szuchman, Larissa Anderson, Julia Simon, Sofia Milan, Mahima Chablani, Elizabeth Davis Moorer, Jeffrey Miranda, Renan Borelli, Maddy Masiello, Isabella Anderson, and Nina Lassam.

That’s it for “The Daily.” I’m Katrin Bennhold. See you Monday.