Talking about engineering the climate, and treating severe nausea and vomiting during pregnancy
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This is the Science Podcast for April 4th, 2025. I'm Sarah Crespi. First on the show, climate engineers face tough conversations with the public when it comes to testing things like changing the atmosphere to reflect more sunlight or altering the ocean to suck up more carbon dioxide.

Reland science writer Rebecca White joins me to discuss the questions people have about these experiments and how to get collaboration and buy-in for their testing. Next on the show, hyperemesis gravidarum, severe nausea and vomiting during pregnancy, is common in so many pregnant people and can have lasting maternal and infant health effects.

This week, Marlena Faso wrote about her path from suffering HG to finding linked genes and treatments for this debilitating complication. I'm going to be honest that I actually am skeptical about climate engineering changing like the whole Earth system in order to reverse something that we've done accidentally. And this is something that we've published in the news section on, we published in our policy section in Science.

I've read about it. I've talked to people. I actually asked our policy editor, Brad Weibel, why are we trying to test these things when sci-fi movies tell us that it is a bad idea to try to intervene at this scale? And the public does seem pretty averse. And to the best of my memory, what he said was someday some country or some international organization is going to have to possibly decide to do one of these things. There is no better choice but to add this to the arsenal of our climate change weapons.

So we should probably know which one is the most likely to work and have the least side effects in case that time comes to pass. But even getting basic data on geoengineering, testing out deployments, the basic processes you would need to do, has been very controversial. This week in science, freelance science writer Rebecca White wrote about where the rubber meets the road, where the science meets the people, and how bumpy it has been. I

Hi, Rebecca. Welcome to the Science Podcast. Hello. How are you doing? I'm good. I'm good. I'm excited to talk because you really looked at the main question I have about this is how do we make this palatable if it needs to be palatable to the public?

Well, that discomfort that you have, especially around solar geoengineering, which has these ideas to change the atmosphere, to turn back the rays of the sun and stop the planet warming too much, people are really uncomfortable about that. And for good reason. We don't have a good track record of modifying planetary systems without some kind of unintended consequence. Right. And I kind of think about it as, you know, softer nuclear winter. That doesn't sound great. Yeah.

Everything gets sort of lumped together under the terms of climate engineering or geoengineering, but there's two fields within this that are really distinct. And carbon removal, which is vacuuming carbon dioxide out of the atmosphere, that's really, we know we need to do this. It's in the IPCC reports. It's in the model pathways. It's a fairly well-accepted thing. The other side of this, which is solar geoengineering or solar radiation modification, that's not

optional at this point because it doesn't address the root problem of climate change. It doesn't change the amount of carbon dioxide in the atmosphere. So we know that one is fringe. It's not the same, if that makes sense. We're studying it because we may need it, but it's not

on the same level, I suppose. Everybody I talk to is really clear that neither of these fields are going to be any good to us if we don't also reduce emissions at the same time. Otherwise, we're not going to get anywhere at all. So carbon removal, that's filtering it out of the air or perhaps putting something into the ocean to make it take up more carbon?

Suck it out of the air. That's one side. The other side is solar geoengineering. This may be fringier idea, putting something into the stratosphere or maybe just the atmosphere above a city or an ocean that would reflect more light back to the sun.

You actually start your story in California, where researchers decided to test out a type of solar geoengineering. How did that go over? Not well, I would say, from anyone's point of view. What happened was they were doing it.

pretty small test in San Francisco Bay on the deck of an aircraft carrier parked in the city of Alameda. And they didn't tell the city of Alameda what they were doing, but they did tell the New York Times. And so the mayor of Alameda starts reading the newspaper on a Saturday morning and she's like, oh, a controversial test happening in the East Bay. I wonder, okay, which of my neighbors is doing this? And she was like, oh no, it's my town. What?

And that shock, the fact that they hadn't approached or asked or said, hey, this is what we're wanting to do. It just led to the whole project being treated with suspicion, which makes sense. It's a controversial technology. Yeah. And what were they doing in the bay? What was it, in the water or the sky?

It's in the sky. So they're just like spraying saltwater, trying to make mist where the particles are a certain size. And so it's not anything that's dangerous, but it's the meaning of what they're doing and what it's sort of contributing towards. Because the ocean is making salty mist 24 hours a day. But if you don't tell people, you know, when you start launching cannonballs of salt into the air, what you're doing, and they say, oh, it's geoengineering or solar geoengineering,

There's going to be questions. So why are the questions so different? You know, you do see people doing public outreach for things like citing a waste repository, or sometimes I come across it when researchers are going into community and asking questions of that community. The research is about them. You're going to want to collaborate with them. But when you think about climate engineering, it seems like a different ask when you go to the public. What makes this so different for people? With climate engineering,

Under engineering, we don't know how to do it yet. We don't know what the technology is going to look like. We don't know what impacts it's going to have. If we're consulting people because we want to make a new power plant or a landfill, we sort of know what that looks like, who's going to run it, whether it's going to be the city or a private company, you know, and people, they have good questions about these things. They have different views on it depending on

Who's going to be in charge? Who's going to profit from it? Who gets to make decisions about it? What's it going to look like? And so the uncertainty about it makes it a really difficult thing to be able to talk to people about. One of the scientists I spoke to said, you're basically asking people to imagine the future, to imagine different futures when you're talking to them about these technologies. So I think this story that you cover, this one saga of the

I think the company's called Planetary. We got the second half of it on the podcast, actually. Warren Cornwall had done a story. He's a contributing correspondent on this experiment that they're doing off the coast of Halifax where they're trying to change the pH of the ocean. And this is supposed to kind of alter eventually how much carbon is trapped by the ocean and how much is in the air. So kind of changing that ratio, slowing climate change, slowing warming.

And when he told me about it, we did, of course, touch on some of the controversies that have come up in the testing. But this isn't the first spot that Planetary had been to. You actually covered the initial attempt that they had. In Cornwall, over in England, they have a different reception there. Yeah, completely. And it took them by surprise, I think, because they had gone into it trying to do the right thing by that community. They had got a sort of environmental safety report. They'd been going around talking to individual people.

They did talk to the town mayor, for instance, and she was keen. And so when they went to hold these public meetings, they were like, hey, this is us. This is what we're up to. Just sort of presenting it. And people were really like, wait, what? You want to put a chemical in our bay? What they'd missed out on understanding was sort of the history and the culture of the place. Like

there were a few things that were really going against them that sort of put their backs up right from the outset. And that was things like they partnered with a local utility company to do the test. And the utility company is like public enemy number one over there. Everybody,

Hates it. Or the area has a history of people coming in from outside and doing things like crashing oil tankers off the coast and causing Britain's largest environmental disaster. So they're sensitive to contamination, even if it is with good intention. They just are very skeptical. Yeah, there was one moment you report on about like someone asking what happens if this doesn't work or if it's bad.

for the environment. The chief executive of the company was like, "Well, we got our business." And people are like, "Hang on, hang on. That's our bay. That's our main source of income. Most of the region depends on tourism. We've all made sacrifices to live here. This is a very hard place to live, but we're here because we love the coast. It's so beautiful." This company, Planetary Technology, got a better reception in Halifax. Can you talk about how they managed that transition? What was different about this next attempt?

One of the different things is they're from Halifax. That's their home. They've been there for a long time. Their chief scientist had been giving public talks there and engaging with different groups for much longer than they had been able to do in Cornwall. And they're also partners with the local university, which people trust a lot more than a privatized wastewater company. It's just a different set of relationships. And so there's greater public acceptance. Right.

Social scientists have looked into this, how to work with the public, how to explain what you're doing and get their buy-in if it makes sense. What are their recommendations and how often are these geoengineering, these climate engineering teams taking those on board? Sometimes, certainly not always. There's a long history of how to talk to the public about different things that you want to do. And

The best way to do it is to be able to have a two-way conversation. So to be able to take people's concerns and look at them and address them and incorporate them in research. Like one project that I talk about in Australia asked people what they were worried about in a similar like salt spray experiment that they were doing. And people said, oh, well, is the salt going to blow in off the ocean and cover my crops, my crop fields? Are they going to be affected by the salt? And the researchers said, oh, well,

We don't know. Let's find out. And so they looked into it and they found out that, well, lots of salt blows in off the sea all the time. The amount that we produce is going to be a tiny part of that. So no, it's not going to affect your crops. It's not going to rust your cars more than they would normally rust, for instance. But that...

That conversation means that people feel they can be part of directing what research happens and making decisions about being informed about what it is and what it's going to involve. Yeah. Would you say there are any kind of like recommended rules or guidelines or keys to trying to get community buy-in that social scientists have been able to discover? It really should be an ongoing relationship, not a one-way thing where you just tell a community a whole lot of information and then they're like, yeah, what?

No, it's this continual process where people feel like they're able to, and they are able to express their concerns, discuss them. The consulters are not afraid of people who are unsure or angry, or there's just space for all of that to happen in. And if that happens, research shows that they're actually able

is much more likely to eventually bring people around to an idea that they may have been reluctant towards in the beginning.

simply because they need space to express and talk through what their issues are. People know when something isn't genuine and it's not genuine unless they sort of have the ability to be like, no, I don't like this. I do feel like this is kind of pushing off the bigger consent question. So going into a town and talking to the mayor or the locals and saying, well, what do you think about this intervention? And we're going to trust this out here. That's different than saying we are going to make a concerted effort to change

change the amount of carbon dioxide there is in the air globally using this technology, and that could affect everyone. When are those conversations going to happen?

Well, we all want to know. And it's hard to find the borders for carbon removal, especially. It's hard to find the borders of when you should do that or not, because technically, like planting a forest is carbon removal. We don't usually consult people about that. People are generally keen on trees. It's more when you are making large facilities or you're testing these unknown new technologies that you're going to want to talk to the people along your coastline or who are going to be next to this big factory.

factory-like thing that's going to vacuum carbon dioxide out of the atmosphere. You want to talk to people about those. Yeah, because it has to be pretty massive to undo the work of centuries of digging carbon out of the ground and putting it into the air, right? Yeah, we know that we need to do a lot more carbon removal than we are currently doing. If we want to keep warming to less than two degrees, the IPCC says so. It's pretty well accepted. We can't just plant a lot of trees everywhere. It could be cool. I am a big fan of wood vaulting. You guys can look that up.

We had it on the podcast. It is very low impact, very low tech and does promise to lock up a lot of carbon, but it's just almost too low tech for this conversation.

It doesn't seem to cause problems. Yeah, that's what I've heard too. And I'd love to see it. And they're almost more ready for this how much to do and when should we do it conversation than some of these other things we're talking about, like changing the ocean pH, changing aerosol content in the atmosphere. Yeah, well, the really difficult one is the solar geoengineering one because that potentially has impacts that are so much bigger than a community or region or nation. And so that's the kind of thing that

A lot of the most prominent researchers in the field, David Keith has told me, we need citizens assemblies for this. We need to deliberate this at a really large scale and really inform people what it is, why we would want to do it and start talking through situations in which we may want to use it. Yeah, I mean, we did see what kind of you would call a natural experiment where we changed the rules.

rules on shipping and that changed how much aerosol was coming off of boats. And that has shown to have an effect on the atmosphere. Yeah. By accident, the ship's pollution was brightening clouds over the ocean. And without those clouds, the ocean's dark. It absorbs sunlight and gets warmer. With the clouds there, the sunlight doesn't hit the sea and you don't have that temperature increase. And

Was that an example of inadvertently sort of trying to do the right thing by emissions and actually causing an effect that you didn't anticipate? I hadn't heard of this one that you talk about that's being tested in Long Island, New York, and one of the Carolinas. And this is putting something on the beach. Can you talk a little bit about that approach? Yeah.

Yeah, exactly. So its intention is also to change the pH of the ocean to make it less acidic or alkaline, but to do it by a different method, which is you sprinkle sand made of certain types of rocks that are really alkaline in the tidal zone. So they dissolve in the wave action and release the alkalinity over time. That's also a natural process. Rivers turn over those rocks as they flow to the sea, and that's how the sea gets some alkalinity. The idea with that is, again, that you'll change the pH of the ocean. It'll

absorb carbon dioxide more quickly. There's a company that is testing that, has done in a couple of places in the US and yeah, has had quite a good reception because of its sort of very gentle consultation with communities saying, here we are, here's our idea. Do you want to try this? And its very first test site, which is on Long Island, the community were like, yeah,

Cool. We'll have the world's first geoengineered beach. We'll be part of the monitoring. We'll keep an eye on it. The rock they use has a little greenish tinge. It's kind of minty colored. How long do we see the greenish sand stay there before it gets mixed up? Seems like from your story that concerns about geoengineering, about climate engineering are not evenly distributed around the whole world.

You can have a lot of assumptions about what other people think of these technologies. For instance, there's more than one Global North group that is really worried about solar geoengineering because they're like, we can't do this to the Global South. This is a social justice thing.

And then if you actually start studying what the public in different areas think of these technologies and whether or not they want them, the research is still in its early stages, but it finds that people in the global South are way keener on things like solar geoengineering than people in the global North. They're like, yeah, we're already experiencing the effects of climate change. If there is something that could locally cool down my area, that sounds great. And young people as well are more interested because they're

Thinking, obviously, we're going to have to live with this a while. Maybe we should explore some of these options, whether or not

We use them. I think with solar geoengineering, there are a lot of arguments against it saying it's dangerous even to study this technology because that leads us towards deploying it. But then the counter argument is, well, we could either know how to deploy it well and maybe not cause global famines. You know, we could do it tomorrow because we know that it works. Volcanoes have been doing it for ages, but we don't know how to do it without causing 18, 16 year without a summer. Yeah.

So those are the various arguments of White. All right. Thank you so much, Rebecca. Thanks, Sarah. It was fun. Rebecca White is a freelance science journalist based in New Zealand. You can find a link to the story we discussed and a wonderful graphic and timeline at science.org slash podcast. Stay tuned for new insights into treatment of the pregnancy complication, hyperemesis gravidarum.

I was lucky during my pregnancy. Everything around me smelled terrible. I was nauseated for about three months, but I never threw up and those feelings did go away as the months ticked by. But other people experience a much more extreme level of nausea and vomiting. It doesn't stop. And they lose weight, they lose fluid, they might end up very, very sick and on bed rest or even hospitalized.

Until recently, clinicians had very few clues to why this pregnancy complication called hyperemesis gravidarum occurred. This week, Marlena Faso is the winner of the BioInnovation Institute and Science Translational Medicine Prize for Innovations in Women's Health for her essay, On the Path to a Cure for this Debilitating Complication. Hi, Marlena. Welcome to the Science Podcast.

Thank you for having me. So I'm so glad you could be here. And, you know, you start your essay with your own experience of HG, which is what I'm going to call this because I think it's a little easier to say. Can you talk a little about what happened to you? Yeah. So you were lucky. I did have the very severe form, which happens in about 2% of pregnancies. And so I

My nausea and vomiting was so severe that I could not eat, drink or move without violently vomiting. That means I couldn't get up to go to the bathroom. I could not shower. I couldn't brush my teeth. I just had to lay completely flat and still every waking moment of every day. And so it really was a form of torture. My doctor put me on seven different drugs at once and IV fluids, but nothing helped.

Eventually, I was given a feeding tube, but it was too late and I ended up losing the pregnancy in the second trimester. Wow, that is awful, especially there's nothing they can do to stop it at this point, right? They tried all these anti-nausea meds on you. They tried to give you food and you're just locked in. Yeah, it was torture. Yeah.

And as you mentioned, this is, you know, about 2% of the population of pregnant people suffer from this. And there can also be effects on maternal and infant health, right? We've known for quite a while that there are increased risk of poor outcomes like preterm birth and small for gestational age babies. But now these long-term outcomes are also coming out for the mother, increased risk of postpartum depression and PTSD, especially if it lasts all nine months, and for the child.

There's numerous adverse outcomes that have been recently reported, like increased risk even of smaller brains at age 10, neurodevelopmental delay, even increased risk of childhood cancer, respiratory disorders, and even cardiac anomalies. Wow. So your own experience kind of set you on the path to looking into the root causes of this and potential treatments.

You started with a genetic approach. Can you talk a little bit about like the groundwork that you laid for this? Yeah. So I didn't have it in my family, so I wasn't sure if it was genetic. So the first step was to see if there was evidence for that. And so I partnered with Kimber McGibbon at the Her Foundation and we put out surveys to see if it ran in families. And we did the first familial aggregation study of hyperemesis that showed that

It did run in families. In fact, there was a 17-fold increased risk of having it if your sister had it. We also did a recurrence risk study that showed a high recurrence risk of 80% chance of having it in a second pregnancy if you had it in the first pregnancy. And so those two pieces of evidence supported the possibility of a genetic component. Then you say, okay, what genes, right? What might be different in these related cases? And what did

What did you find were the targets here? Yeah, so I found two genes in the first study, which was in a partnership with the personal genetics company 23andMe. And one of the genes, the star of the show, was a gene called GDF-15 that codes for a hormone that causes nausea and vomiting and that is expressed at the highest levels by the placenta, higher than any other normal healthy tissue in the human body. Oh, wow. Yeah.

And then the other gene, fascinatingly, was a gene called IGF-BP7. And that gene codes for a protein that is analogous to the same protein that also is upregulated at the initiation of the maternal death spiral in the octopus. So let's just stop there for a second because that was like a long lead up. So we actually had a

A conversation about this on the show like two weeks ago, the fact that a lot of octopus females and even a lot of the males, as soon as they start reproducing, that's the end of the story for them and they start to die. And this is the death spiral protein. This is associated with that. Yeah. So it's one of three proteins that are upregulated at that initiation in the maternal octopus when she lays her eggs.

So it really suggests that this behavior is an ancient behavior that evolved even before we diverged from octopi. So it's a very old mechanism that we probably don't need anymore because now it's really...

We prefer to survive after. Yeah, well, now we can safely go out to eat and get food without much risk. You can just push Uber Eats on your phone. But for the octopus, it's still really risky. If you watch the Netflix documentary, My Octopus Teacher, it's

It shows how dangerous it is every single time the octopus goes out, the risk of getting eaten by a shark. Yeah, so clearly in that severe example, you can see that the benefit of staying with the eggs outweighs the risk of surviving. It's really incredible.

Well, we probably have some other slightly different use for that protein today in people, but it is interesting to see that it's stuck around in animals for so long. But let's go back to what we call the star of the show. This is the one that's specifically associated with nausea and vomiting. Is the gene different in the people who have HG or is it overexpressed, underexpressed? What do we know about that?

Yeah. So that's also an interesting story. So we found three different genetic variants in GDF-15 that are associated with increased risk of hyperemesis. So more patients have them who have hyperemesis than don't. So since it is a nausea and vomiting hormone, you would think that it increases the levels of the hormone. But actually what we found in a partnership with a whole international team, but we

The main doctor was Dr. Stephen O'Reilly, an endocrinologist that I partnered with for this study, was that actually the genes are coding for lower levels of this hormone. And so what we found was going on is that before pregnancy, these women who have this gene are at increased risk because they have lower levels. And so they become hypersensitive to the rapid rise of this hormone during early pregnancy.

Oh, interesting. You also link this to what's going on with the fetus, right? Because the fetus itself could have one of these variants as well, and that can change their expression. Yes, exactly. So that was also fascinating because we know that there can be variation from one pregnancy to the next with the levels of vomiting. And so I looked at my patients that had the mutation that increased their risk tenfold, and I sequenced their children and found that...

It was actually that when the child inherited that mutation, also that the mother had less nausea and vomiting. So she was at increased risk because she made less before, but then if her fetus inherited it as well, her risk went down compared to if the fetus inherited the gene that makes the higher levels. So did this point to some interventions for you? Like once you found out that there was this link between...

the levels of this protein and what was going on with vomiting? Yeah, so that's the very exciting part. So this...

has two approaches now that we can use. And one is to try to prevent it before pregnancy by increasing the levels. The approach I'm taking is with metformin, which is a medication that we know increases your circulating levels of GDF-15. So then we can desensitize patients hopefully to it so that they are not as sensitive when they become pregnant. Metformin is

It's a pretty common medication that's been around for a while and has been tested on many different people, right? Yeah, it's a very common medication. It's equitable because it's available in generic and it has already been used in this timeframe right before pregnancy to increase fertility in patients with PCOS. So it has a pretty good safety profile. So it's a great solution if it works.

And then there's also the people who don't know they're going to have this. And so they get it during pregnancy. We also have a new approach for them, which is to lower the levels of GDF-15 or GFRAL, the receptor for GDF-15, to block it to try to lower the signaling of nausea and vomiting in pregnancy. And so it's really exciting because there is a

a antibody out there that is currently being tested by NGM Bio. It's called NGM 120 and it blocks this pathway and they have treated the first patient they announced in February this year. So there's an ongoing trial based in part on my work. So that's very exciting for me.

Well, that's really good news. As you say, the equity there, the ability to distribute it to so widely is so important because it is torture to feel nauseous. It's awful to be malnourished. Yeah. And at a time when you know you're supposed to be eating healthfully and you just can't.

It's really torture. All right, Marlena, what did I miss? I would just like to add, I do recommend for people who are going through hyperemesis to visit the HER Foundation website because we have so many resources available. We have support groups, information and protocols for doctors that...

that are designed by doctors and clinicians. So I think it's a great resource for people to help them through this. That's great. And you don't have to spell hypermesis in order to find the website.

So that's the Her Foundation website. You can find it on Google. Thank you so much, Marlena. I'm really glad we got to talk about this and congratulations on winning this prize. Thank you. It's an honor. Marlena Fazo is a scientist at the Center for Genetic Epidemiology in the Department of Population and Public Health Sciences at the Keck School of Medicine at the University of Southern California. You can find a link to her essay and find out more about the STM and BII Innovations in Women's Health Prize at science.org slash podcast.

And that concludes this edition of the Science Podcast. If you have any comments or suggestions, write to us at sciencepodcast at aaaas.org. To find us on podcasting apps, search for Science Magazine or listen on our website, science.org slash podcast.

This show was edited by me, Sarah Crespi, and Kevin McLean. We had production help from Podgy. Our music is by Jeffrey Cook and Wen Kui Wen. On behalf of Science and its publisher, AAAS, thanks for joining us.

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