DAVID GREENE, HOST:
The United States shut down its largest border crossing with Mexico over the weekend.
RACHEL MARTIN, HOST:
Yeah. This happened after a peaceful demonstration by Central American migrants then turned out of control. Hundreds of people near the U.S.-Mexico border were marching to protest U.S. immigration rules, specifically the long wait to process asylum claims. Then they started to walk sort of en masse across the Tijuana River. They pushed past Mexican police and continued toward the border crossing into San Diego. Some of them even tried to get through the fence in a wire barrier. So in response, the U.S. closed the crossing for a few hours. And Customs and Border Protection officers ended up firing tear gas at the migrants.
GREENE: And let's hear more about what that scene was like from reporter James Fredrick, who joins us this morning. He's in Tijuana. Good morning, James.
JAMES FREDRICK, BYLINE: Morning, David.
GREENE: So describe the border yesterday. What was this like?
FREDRICK: Well, so it started as a march. And there were a lot of Mexican police out in Tijuana trying to stop the march, stop it from getting close to the border. But they kind of found their way around Mexican police. And then as Rachel was saying, they eventually got to this kind of river bank where there is not a full metal fence but some razor wire and things like that. It wasn't as large of a crowd there. But some people started pushing their way through, maybe trying to squeeze their way through the fence. And that is when we saw tear gas being used to get that crowd away from the fence. And tear gas was used several times. And it was really windy yesterday. So even people who weren't close were hit by this tear gas as the wind carried it across this kind of river channel. And so, you know, we saw found women and children, you know, being hit by tear gas. And it really quickly turned into a pretty chaotic scene.
GREENE: Wow. It sounds like a pretty chaotic scene.
FREDRICK: It went from being a march and then people not going to go, and then, yeah, it got scary pretty quickly.
GREENE: So I know that the U.S. authorities shut down the border for a while. And, I mean, it was on a Sunday. It's only a few hours but this border crossing - I mean, something like 100,000 people enter the U.S. from Mexico. I mean, this is no small thing that this border was closed.
FREDRICK: No. It's really hard to overstate how important this border crossing is. And, I mean, we're not talking about tourists going over the border. I mean, these are people who commute - either dual citizens or people who have citizenship and then residency in another country and cross over to work or to go to school. As you can imagine, yesterday, you know, being a holiday weekend, there were lots of people traveling here. I've also seen lots of people coming down from California to come bring donations for the caravan. And then this border was shut. So, you know, for both business and, you know, people who need to cross for any other kind of daily reason, I mean it is a massively important border. Even when it shuts for a couple of hours, it causes the total chaos here.
GREENE: OK. And you mentioned the word caravan. I mean, this this has been part of the political conversation for weeks now. So you still have thousands of migrants in Tijuana waiting to apply for political asylum, more moving up through Mexico. How are Mexican authorities responding to this?
FREDRICK: Mexican authorities are just trying to keep things calm. They do not want, as President Trump has threatened, a total border shutdown. And so they're trying to keep things together. The question is, where are the resources going to come from to take care of these thousands of people who are here in Tijuana? Because there are just not enough resources for them there in Tijuana right now.
GREENE: Reporter James Fredrick in Tijuana this morning. Thanks a lot, James.
FREDRICK: Thank you.
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GREENE: All right. So designer babies could be more within reach as of today.
MARTIN: All right. So a Chinese scientist claims to have created the world's first babies whose genes have been edited to be immune to HIV. This is obviously highly controversial in the scientific community for a lot of reasons. But the scientist who did this, He Jiankui, says it's a breakthrough. He says the baby's father has AIDS, but they will not.
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HE JIANKUI: No gene was changed except the one to prevent HIV infection. The girls are safe, healthy as any other babies.
GREENE: All right. Let's bring in NPR's health correspondent Rob Stein, who has been reporting on gene editing in China. Hi there, Rob.
ROB STEIN, BYLINE: Oh, hey there, David.
GREENE: OK, so this scientist is downplaying the impact of this, but this is a very controversial thing that seems to have happened here. So who is this scientist, and what did he actually pull off?
STEIN: Yeah. So he works at the Southern University of Science and Technology in Shenzhen, China. And right now he's actually in Hong Kong, attending an international summit on human gene editing. And he claims to have used his powerful new kind of genetic engineering called CRISPR to make changes in human embryos. And he said he did this, as you mentioned, to make babies that are born genetically immune to HIV, the virus that causes AIDS, by essentially kind of genetically blocking the doorway that HIV uses to infect cells. And he even claims that two twin girls were born from embryos genetically modified this way a few weeks ago. And in a video posted online, he says the girls - their names are Lulu and Nana - appear healthy and are at home with their parents, Mark and Grace.
GREENE: Wow. So how is the scientific community responding to this? Do they see this as a really controversial moment?
STEIN: Yeah, this is extremely controversial. You know, a lot of scientists think this sort of thing may be OK someday to try to prevent the long list of terrible diseases. But even advocates of editing human DNA like this say that, you know, this is happening way too quickly, and it's way too premature. I actually spoke to Jennifer Doudna. She's a scientist in California who helped invent CRISPR. And she has big concerns about this. And one big concern is safety, you know, for the kids - any kids born this way and that if scientists make some sort of mistake, it could kind of mess up the human gene pool for generations. And then there's the concern you kind of alluded to in the intro about designer babies.
STEIN: I mean, you know, where do we draw a line on this? If scientists do this for medical reasons, what's to stop them from doing it for other reasons - to make taller babies, stronger babies, smarter people.
GREENE: Yeah, it could open the door to a lot. But you do mention that this sort of thing could one day be OK to help prevent people from having disease. So what happens now?
STEIN: Yeah. So the first big question is, you know, did the scientist really do what he says he did. You know, it seems plausible. This is a valid line of research that's been underway for a while. But this is not how science usually works. You know, something as potentially historic is this - you know, and some people are comparing this potentially to the birth of Louise Brown, the first test-tube baby. You really should subject to science - to really careful review by other scientists to make sure it's valid before you release to the public like this. And there's a big meeting going on in Hong Kong right now where hundreds of the world's leading scientists are gathering to discuss just this sort of thing. You know, should scientists be doing this? Where should we draw the line? Is this ethical? And how do we approach this kind of thing safely and carefully?
GREENE: NPR health correspondent Rob Stein. We appreciate it, Rob. Thanks.
STEIN: Oh, sure. Nice to be here, David.
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GREENE: So climate change is causing more frequent and more severe weather across the United States. And unless there is dramatic change, this is going to cause deep damage to America's infrastructure, America's ecosystems, health and the U.S. economy.
MARTIN: Yeah. All this is according to the most comprehensive federal climate report to date. It was a huge report, more than a thousand pages, mandated by Congress. It's based on research by hundreds of scientists. And it came out on Black Friday. That's when the White House issued this thing. So Black Friday - it's known as a pretty slow news day, a lot of shopping...
MARTIN: ...Not many people paying attention to news. But obviously, David, there are huge questions about the report, what it says about our collective future.
GREENE: Yeah. And let's bring in NPR's Rebecca Hersher. Hey there, Becky.
REBECCA HERSHER, BYLINE: Hey there.
GREENE: So we talk about what this says about our future. But it's also - this report is saying things about our present, right? I mean, it says we're actually feeling the effects of climate change right now in the United States, without a doubt.
HERSHER: Absolutely. So the most obvious and widespread thing is extreme weather. So large fires are getting more frequent. That obviously rings true for folks. The number of acres that are burning each year is already going up. That will increase as the Earth gets warmer. And it's not actually only the western U.S. We're about the Southeast. The Southeast is projected to burn more, as well, in the future. And then, of course, there's flooding. So flooding is one of the really big ways that Americans actually experience climate change day to day. And flooding from hurricanes are getting larger and wetter 'cause the air in the oceans are getting warmer.
But we're also talking about flooding from thunderstorms, like regular rainstorms. And one thing that climate change does is it drives extreme rain. So when it rains - I'm really sorry, David - it pours. And that kind of rain causes flash floods. It causes landslides after fires. And extreme rain is getting worse in pretty much every part of the U.S. That's one thing that the report makes really clear. And then there's financial cost. So climate change is extremely expensive. If the Earth keeps warming - this is a big takeaway - we could be looking at billions of dollars in costs every year.
GREENE: Well, but isn't the interesting thing here with this report - it comes from the Trump administration. But this is a White House that, you know, is issuing more than a thousand pages of research here but has also been really notorious for doubting whether climate change even exists. So what impact does this report have?
HERSHER: Well, I think the first thing to remember is that this is a scientific report. You know, it doesn't tell Congress or the White House what to do about climate change. That said, it lays out in pretty stark terms, honestly, that the climate is already changing and that humans are driving it. That is not up for debate. The science has been clear for a long time. So it could be used, a report like this, for example, to challenge deregulation attempts by agencies like the EPA, right?
So if you're trying to roll back emissions standards, for example, it's going to be really hard - increasingly difficult, honestly - for anyone to argue that keeping emissions where they are won't have any negative economic effects, let alone health and safety effects for Americans. So you could see this showing up in court. You know, there are a lot of challenges to deregulation. And you could see Congress using it to justify things like postdisaster resilience spending, again saying, clearly, this is happening. We want to spend money on it.
GREENE: Does this report say that there's been any progress in confronting climate change?
HERSHER: Yes. Yeah, there has been. I mean, you know, the Trump administration has been rolling back climate legislation. But climate adaptation is actually happening in America. It's just happening at local, state and regional levels. So we're talking about things like water conservation. We're talking about forest management and infrastructure updates. You know, we're talking about building floodwalls and raising highways and clearing brush, even things like burying power lines. You know, there's an old saying that emergency spending could refer to anything. But, really, climate spending could be anything. But this is a big deal.
GREENE: All right. NPR's Rebecca Hersher. Rebecca, thanks so much. Transcript provided by NPR, Copyright NPR.