JOHN DANKOSKY: This is Science Friday. I’m John Dankosky.

MAGGIE KOERTH: And I’m Maggie Koerth. I’m a science journalist, editorial lead at CarbonPlan.org, and sometimes news roundup guest. And I’m happy to be filling in for Ira today. Later in the hour, we’ll talk about the challenges of reining in plastics pollution and the global trouble with bananas.

JOHN DANKOSKY: But first, Monday is Earth Day, and we wanted to highlight a few positive trends and some promising solutions to the climate crisis. It’s easy to feel pessimistic about the future of our planet. And though there’s so much more to do, we have made some key strides. So joining me now to talk about this and some other top science stories of the week is my guest Casey Crownhart, climate reporter at MIT Technology Review.

She’s based in New York City. Welcome back. And happy almost Earth Day, Casey.

CASEY CROWNHART: Happy almost Earth Day, John. Happy to be here.

JOHN DANKOSKY: Yeah, I’m glad you’re here. So let’s start with electric vehicles. Their growth has really exploded just in the past few years.

CASEY CROWNHART: Absolutely. I think it’s just wild to think about, just a few years ago, these were such a niche thing. And now, globally, about one in five new vehicles sold last year were electric, either fully battery or plug-in hybrid. So it’s just wild to see how quickly this has become such a normal thing on the roads.

JOHN DANKOSKY: Yeah, such a normal thing. Of course, you EVs have their own problems, but that growth probably is a really good thing for the environment long term.

CASEY CROWNHART: Absolutely. These cut emissions by a lot, and transportation is one of the biggest problems we need to clean up. So that’s definitely– I count that as positive news.

JOHN DANKOSKY: OK, so maybe this is part of it. But there’s some data showing that we’re also making progress toward that 1.5 degrees Celsius increase in global temperatures per year. This is the threshold we’ve been trying to get to. How are we doing?

CASEY CROWNHART: Yeah, we’re definitely kind of on our way. So like you mentioned, the world set this target of keeping global warming well below two degrees C or ideally below 1.5 because we know things get pretty bad after that. And so the Paris Agreement set that target in 2015. At that time, we were on track for anywhere between 3 to 5 degrees C of global warming. Now we’re on track for about 2.7.

So definitely, like you said, a little bit off that– or a lot bit off that 1.5 C. But we’re on track for a better future than we were almost a decade ago. So I also count that as good news.

JOHN DANKOSKY: Yeah, it seems like things are trending in the right direction. I guess another trend that’s happening is that the costs of renewable energy really have been dropping. And they’re dropping pretty substantially. And that might account for some of this progress we’re making.

CASEY CROWNHART: Absolutely. I think especially when you look at solar and wind, batteries also fall into this bucket. Solar and wind today can be one of the cheapest ways of producing electricity. And that was a decade or a little bit more ago, they were among the most expensive. So that’s just another push that we’ve seen towards making progress on climate.

JOHN DANKOSKY: And I guess amongst all of the renewable energy sources that we have, wind projects have really been picking up steam, I suppose. What have you found on wind energy and how much it’s been growing?

CASEY CROWNHART: Yeah, so there was a big report that came out tallying up what wind installations looked like from last year. And globally, there was about 117 gigawatts of new wind-power capacity–

JOHN DANKOSKY: Wow.

CASEY CROWNHART: –added in 2023. That sounds like a lot, and it is. But what I think is even more important is that that’s 50% more than what was added the year before in 2022. So we’re seeing this growth, and we’re seeing accelerated growth, which is, again, this is one of the staples of getting our electricity supply cleaned up.

JOHN DANKOSKY: Sure. But I guess when we see that global growth, there’s more growth in some places than others. The US has fallen behind some other countries, of course.

CASEY CROWNHART: Yeah. We’re seeing definitely this is localized in some places. So China is absolutely leading everybody else on both onshore and offshore wind-power installations. That’s the case for a lot of other climate technologies as well.

But the US and Germany are catching up a little bit, installing a lot. Wind is getting installed everywhere. But yeah, like you said, definitely faster in some places than others.

JOHN DANKOSKY: One of the things I know that you’ve heard, I’ve certainly heard for years of covering renewable energy sources, is that we can’t put enough online in the US because our power grids just aren’t ready to accept it. Now, I guess there’s a new report, Casey, from UC Berkeley that suggests a potential solution to this problem could be something called advanced reconductoring. Can you explain what exactly advanced reconductoring is?

CASEY CROWNHART: I know. This is a term that sounds so hard to parse. But it’s really interesting. So like you said, we have a lot of projects just waiting to get onto the grid because the grid needs upgrades. And it takes a while to get all the permits and everything.

One potential solution to our aging grid is advanced reconductoring. And basically what this is like a renovation for power lines. So today, most power lines have steel cores. And then they’re surrounded by aluminum. Advanced cables can be made with different materials.

So you can take out that steel, and you can put in lighter materials like carbon fiber. And so then a power line can do a lot more. It can carry as much as twice the current as older power lines could.

JOHN DANKOSKY: But so, by swapping out these power lines, it seems though more clean energy could actually be generated in the US because the grid would be able to accept it. How much more, do you think?

CASEY CROWNHART: Yeah. As far as transmission capacity, we could add as much as four times more transmission capacity by 2035 as what we’re on track to do, which would be, like you said, absolutely huge for getting more projects on the grid.

The one caveat is that if we are building projects in new places– so say there’s some sunny remote area where there wasn’t a lot of power lines before, you’ll probably still need to build new lines to get to those places. But this could be really big for getting more projects on the grid.

JOHN DANKOSKY: There are, of course, a lot of wide-open spaces in the US. Is this a scalable thing in the US? I know other countries are doing it. But sometimes those are places that are more densely populated.

CASEY CROWNHART: Yeah, that’s a great point. There are countries that have made progress on this. The problem in the US is actually that our electricity system is very fragmented.

There are thousands of utilities that are in charge of electricity. There’s this crazy patchwork of regional planners and regulators. So there’s a lot of cooks in the kitchen here. So that’s one of the major barriers to making big progress with transmission and the grid in general.

JOHN DANKOSKY: So just this week, you wrote about a fascinating bit of clean energy technology, thermal batteries. Tell me more.

CASEY CROWNHART: This is something I’ve been absolutely fascinated by recently. Listeners might have heard of regular batteries that use chemistry to store energy. Thermal batteries basically do the same thing but with heat. And this is really– could be crucial in cleaning up heavy industry because heat in industry makes up about 20% of all energy demand. Global energy demand is used in heat in factories and industrial centers. And so we’re seeing these companies come up with these really funky solutions to store heat in things like bricks and blocks to use in their industrial processes.

JOHN DANKOSKY: Oh, this is interesting. So the manufacturing process throws off heat. It gets stored in these thermal bricks. And then it’s able to be reutilized somehow.

CASEY CROWNHART: Yes. So that’s part of it is there’s this ability to soak up waste heat. But some people are also building these solutions that can take in electricity. We talked about solar and wind power, which, as we all know, those are only available sometimes when the sun is shining, the wind is blowing. And so if you take that electricity and you turn it into heat, then that heat can be more cheaply stored and then used later in an industrial process. So it’s really interesting.

JOHN DANKOSKY: OK. I’ve got one downer story here, Casey. We’ve been talking about a lot of really positive things for the Earth. Scientists announced this week that there’s another global coral bleaching event. What’s happening here?

CASEY CROWNHART: Yeah. I think it’s important to remember that there are still a lot of these challenges and these effects on the planet that we’re already seeing because of climate change. And so scientists announced this week that coral reefs around the world are experiencing global bleaching. This will be the fourth time that this is happening.

So basically, reef bleaching is when, in warmer waters, stressed coral can expel the algae that live inside them that are their food source. That’s what gives them their color. And so if this happens and if it’s severe and long lasting enough, then coral can die. So it’s a really, really awful thing that’s happening around the world.

The last time this happened was in 2017. It lasted three years. And so this is the second worldwide bleaching event that we’ve seen just in the last decade.

JOHN DANKOSKY: Since we’re talking about rising ocean temperatures, I guess we should mention a weird type of organism that might actually be able to survive some of these higher temperatures. They’re mixotrophs, part plant, part animal. What exactly are they, Casey? And what did this new study find?

CASEY CROWNHART: Yeah. This is a really funky story. We tend to think of autotrophs, which make their own food, and heterotrophs, like animals, which eat other organisms to get their energy. But there are these funky little creatures in the ocean called mixotrophs that are somewhere in between.

So maybe they do some photosynthesis but also eat tiny plankton, something like that. And so scientists found that, during heat waves in the Gulf of Alaska, mixotrophs tended to make up a larger portion of the plankton during these heat events. And so it suggests that these creatures, because they have multiple ways to survive, are able to adapt to these changing conditions.

JOHN DANKOSKY: It sounds pretty smart. Maybe we should all be more mixotrophy so that we can adapt better to what’s happening.

[LAUGHTER]

CASEY CROWNHART: Absolutely.

JOHN DANKOSKY: OK, let’s step into the animal kingdom entirely. Here, scientists have successfully cloned two more black-footed ferrets. Why exactly is this a big deal other than the fact that now the world has two more really cute ferrets?

CASEY CROWNHART: Oh, my gosh, they’re so cute.

[LAUGHTER]

So black-footed ferrets, once scientists thought they were entirely extinct. These have been threatened for a long time. But the US Fish and Wildlife Service announced on Wednesday that they had cloned two black-footed ferrets their names importantly are Antonia and Noreen. And this is important because, at one point, there were only a few of these little creatures running around.

And so all black-footed ferrets in the wild today descend from just seven individuals. And so adding in two more ferrets could potentially really help with genetic diversity and help increase the chances that these little creatures can recover.

JOHN DANKOSKY: OK. So this last story is a really cool animal story. It’s one of those times a lab accident can lead to a scientific breakthrough. It turns out that hibernating bumblebees can survive being submerged into water for up to a week. What?

CASEY CROWNHART: I know. This is absolutely wild. It makes me feel better about all the lab accidents I may have caused when I was in college. So yes, this Canadian University, they were studying bumblebees.

And they had a few hibernating Queens. Basically stored in the fridge. They had them in these like little soil-filled tubes. And one of the researchers realized that one of these tubes had gotten moisture inside.

And so a few of the bees had been submerged in water. But they took them out. And the queens woke up, and they were OK. And so they looked into this a little bit more and found that, when they would submerge hibernating queen bumblebees in water, about 80% of them could survive for up to a week.

It’s really interesting. It’s likely because, when they’re dormant and they’re hibernating, they drop their metabolism rate a lot. And so they don’t need very much air at all.

JOHN DANKOSKY: I think that’s a great place to end this Earth Day edition. Nature’s just amazing, Casey, isn’t it?

CASEY CROWNHART: Absolutely.

JOHN DANKOSKY: Casey Crownhart is climate reporter at MIT Technology Review. Casey, always good to have you.

CASEY CROWNHART: Thanks so much. Great to be here.

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