captioning sponsored by newshour productions, llc >> brangham: good evening on this independence day. i'm william brangham. judy woodruff is off. on the newshour tonight: north korea claims it successfully tested a long-range missile capable of reaching the u.s. what options remain for the trump administration? then, relocating the bushmen. after being forced out of their homeland, the struggle for the few remaining hunter-gatherers in botswana to preserve their culture. >> officially, nobody is allowed to return. over the years, some have tried to recreate life in the villages, but they say it's just not the same. >> brangham: and, what's the buzz on a new beer? how a lab discovered a new type of yeast from bees, that's changing the game for beer makers. >> we actually think, based on some work from colleagues in italy, that it's very likely

that those first beers and breads were relying on yeasts from insects, too. >> brangham: all that and more, on tonight's pbs newshour. >> major funding for the pbs newshour has been provided by: >> bnsf railway. >> and with the ongoing support of these institutions: >> this program was made possible by the corporation for public broadcasting. and by contributions to your pbs station from viewers like you. thank you. >> brangham: it was north korea's own version of fireworks

for the fourth of july-- the communist state today fired off a new missile that may, some day, put the united states within range of its weapons. nick schifrin begins our coverage. >> reporter: on this july 4, north korea declared independence from what it called american nuclear threats. >> ( translated ): the scientists and technicians have successfully test-fired the newly developed inter- continental ballistic missile. >> reporter: in pyongyang, north koreans celebrated what appears to be north korea's most advanced test in its long pursuit of a nuclear weapon. the missile flew for about 40 minutes almost straight up, reaching an altitude of more than 1,500 miles, and came straight down, landing 580 miles away in the sea of japan. on a flatter trajectory, it's estimated the missile could have traveled as far as 4,000 miles-- past anchorage, alaska, says scientist david wright. >> if they shoot it essentially straight up in the air, it goes very, very high and comes down not very far away. if they flatten it out a little bit, it uses all that speed to go a much longer distance. >> reporter: but the test does not mean north korea can deliver a nuclear weapon.

it's not known whether it's mastered required miniaturization, or guidance and separation systems, that can take years to develop. >> as you go to longer and longer ranges, there are just much higher stresses, vibrations, the accelerations, so there are lot of forces on this nuclear warhead. we don't know if they've actually done the final steps to have a warhead that they could actually put into one of these long range missiles and have it work the way it's supposed to. >> reporter: as president-elect, donald trump vowed not to let today's event ever happen. as president, he tried to push china to pressure north korea, but he recently admitted that failed. today he addressed north korean leader kim jong-un, tweeting, "does this guy have anything better to do with his life? perhaps china will put a heavy move on north korea and end this nonsense once and for all." but today, china didn't show willingness to apply more pressure. >> ( translated ): we hope all sides can remain calm and exercise restraint, ease the tense situation on the peninsula.

>> reporter: and in moscow, chinese and russian presidents xi jinping and vladimir putin jointly called for the u.s. and north korea to abandon long-held positions, in order to calm the peninsula. >> ( translated ): we agreed to actively promote parallel freezing of nuclear missile activities of north korea, and large-scale joint drills of the u.s. and south korea. >> reporter: north korea has exploited the u.s. independence holiday before, on july 4, 2006, and 2009. but this is their most dramatic test, and their momentum is increasing. they have now launched more missiles in the last three years than in the last three decades. >> i don't see a road block to them being able to continue this process until they got a missile that really had the ability to reach the lower 48 states. i think it's just a matter of time before they reach that point. >> reporter: for the pbs newshour, i'm nick schifrin. >> brangham: we'll look at the implications of the north korean test, right after the news summary. in the day's other news, iraqi soldiers in western mosul

advanced deeper into the last pocket still being held by islamic-state forces. fierce fighting continued in an area packed with civilians. but in baghdad, this evening, prime minister haider al-abadi proclaimed a "big victory" over isis-- or "daesh" in arabic. >> ( translated ): all the displaced must return to their homes. we are continuing to liberate all our land from daesh. the iraqi people ended the myth of daesh in record time, although the world thought that this was not possible. >> brangham: meanwhile, in syria, a kurdish-led militia has breached the heart of the islamic state's self-proclaimed capital, raqqa. the u.s.-backed forces today punched through the wall around the old city and are now pushing into the most heavily fortified portion of the isis stronghold. president trump's first face-to- face meeting with russian president vladimir putin will happen this friday. they'll meet on the sidelines as the g-20 summit begins in hamburg, germany. the white house says there will be no specific agenda for the meeting.

there's word that canada will apologize to a canadian citizen for the alleged treatment he received at the guantanamo naval base. it's widely reported that he'll also be paid nearly $8 million. omar khadr was captured in afghanistan when he just 15 years old. he initially admitted to killing a u.s. soldier, and spent 10 years at guantanamo. khadr says his confession was coerced, and canada's supreme court has now ruled he was interrogated under what it called "oppressive circumstances." in new jersey, the three-day government shutdown is over. democratic lawmakers reached a budget deal last night, and republican governor chris christie signed it into law. christie had been heavily criticized for using a state beach on sunday, after it was closed to the public. the new budget agreement allowed state parks and beaches to reopen for everyone, just in time for the fourth of july. >> pretty excited! we're going to see the statue of liberty, so we're pretty excited to be back here. i mean, i saw on the news yesterday it was closed for budget issues, so we're excited. it's our first time. >> it's amazing that it opened in time.

it's thankful, it's a very special day to reopen liberty park. >> brangham: in maine, governor paul le page also signed a new budget, ending a partial government shutdown in his state. and, in illinois, there was no break in a budget impasse that's now in its third year. republican governor bruce rauner vetoed a $36 billion package, along with a major tax hike. the democratic-controlled state senate quickly overrode the veto. the house took no immediate action. and, the nation marked its 241st birthday today with an array of annual celebrations. fourth of july parades began with one in gatlinburg, tennessee at midnight. that's been their tradition for 42 years. and in washington this evening, president and mrs. trump hosted a white house picnic for military families before the annual fireworks over the national mall. still to come on the newshour: what options does the u.s. have after north korea's missile test? a court orders the e.p.a. to put

an obama-era rule into effect. farmers struggling with a drop in crop prices. and, much more. >> brangham: we return now to north korea and its recent missile launch. today, the united states called for a closed door united nations security council meeting. to address the threat. so what exactly are the trump administration's options, how might it respond? for that, we turn to ambassador christopher hill. he was the chief u.s. negotiator with north korea from 2005 until 2009, and served as u.s. ambassador to south korea. and, by mark bowden. he's a national correspondent for "the atlantic" magazine, and recently wrote a comprehensive cover story titled: "can north korea be stopped?" gentlemen, welcome to you both. ambassador hill, i'd like to start with you first. can you just give me your official reaction to this most recent launch? >> i think it's a very serious

matter. it's pretty clear they've made progress on intercontinental ballistic missiles. from what i can understand, if you sent it at a different pitch, it could actually exceed the 5,000 miles that qualifies it as an intercontinental ballistic missile, so it's a pretty serious matter, and we also understand they made progress on miniaturization, so it's not farfetched to assume in the next two or three years they will have a deliverable nuclear weapon aimed at the united states and the real question is how is the president going to explain that to the american people and perhaps more immediately what is he going to do about it. >> brangham: mark bowden, president trump said he will not allow a nuclear missile to be developed in north korea but this seems to be a large step in that direction. >> it does. in addition to shrinking a

nuclear weapon to go on top of a missile, they already have chemical weapons and biological weapons capable of mass casualty. this is a really serious development. it's easy to say you're going to stop them from doing it but it's not easy to accomplish. >> brangham: ambassador, what is your understanding of what kim jong un wants with this nuclear program? >> well, you know, opinions differ on this. there are some who believe this is a poor, beleaguered country surrounded by larger hostile states who want to do it harm, so why not allow the north koreans to defend themselves. i think it's actually a much more aggressive purpose they have in mind. i think what they're hoping was that to hold american civilians at risk, that is, to have a deliverable nuclear weapon deliverable to the u.s. mainland, they can convince the united states not to exercise their responsibilities in the

treaty with south korea, and i think being north korean is to believe that somehow, if they can get the u.s. out of the equation, they can reunite the peninsula on their own terms. this seems farfetched, but, to be a north korean is not necessarily to believe in the conventional wisdom. i think there are a lot of north koreans who feel there is a lot of pro north korean sentiment in south korea and if only they could get the u.s. out of the equation, they'd do it so i think it's is a very serious and dangerous moment. >> brangham: mark boden, is this primarily a development of an offensive weapon for keeping the u.s. and others at bay while it retakes south korea? >> i do think and agree with ambassador hill that is the primary reason for having this weapon, but it also gives north korea a lot more leverage in that region and certainly in dealing with south korea. it's conceivable, given the

overtures that the new south korean president has made to reopen negotiations with north korea that kim jong un could use the possession of a weapon like this to pressure -- those gages take place without the united states, and i think his goal may well be to get the united states to withdraw from the korean peninsula. >> brangham: ambassador, help me understand this more. we are always told that, while this regime may be a despotic regime, they're not irrational actors and the idea that somehow the u.s. would allow them to invade south korea seems unbelievably far-fetched. >> well, i mean, if you look at the kind of weaponry which tends to be very offensive, tends to be right up there in the front, when you look at, as mark pointed out, their capacities in chemical weapons and biological weapons, if you look at the fact they have some 14,000 artillery

tubes right up there in the front pointing right at the south korean civilian populations, it looks to be a kind of offensively-minded force. i think for a long time they have been dedicated to the proposition they have to decouple the u.s. from the korean peninsula and then a lot of things will fall their way. >> brangham: mark boden, your piece in "the atlantic" laid out what you describe as the four main options for the trump administration to respond and you reply these are largely bad options. can you explain the suite of options the administration has? >> the oven one, people are bringing this up whenever i'm interviewed on the subject is why don't we attack north korea and take out their military and eliminate the threat? and that's certainly doable, but the consequences of that would be horrific, as the ambassador just pointed out. even the conventional weapons north korea has could level seoul, a city of 26 million

people, and when you add, you know, chemical weapons and biological and potentially nuclear weapons, you have possibly one of the greatest catastrophes in human history. the other possibility is to sort of turn up the screws, a series of small-scale military attacks that would ramp up the pressure on north korea, something that could rapidly descend into an all-out conflict. another pocket is to target kim jong un himself and try to eliminate him and replace him. then the last bad option is just to accept the fact that we can't stop north korea from building these weapons and, you know, deterrents -- you know, in this case, it just be assured destruction we can hope might prevent them from using them. >> brangham: last question to you, ambassador. the president seemed time ply in his tweet it's up to china to handle this situation. but we've had three

administrations to try to persuade china to act with regards to north korea. why hasn't that happened yet? well, i think the chinese are split. i think some chinese feel the demise of north korea would be perceived in china as a victory for america and defeat for china and they worry about the perception of that within china, that is it's a domestic issue within china. so a lot of people want to go with reforms much faster than xi jinping does, and if north korea were to go away, perhaps those people would be in the ascendancy. so a lot of party types, kurt types in china don't like to see something that results in something that looks like a u.s. victory. that said i think the three administrations are absolutely correct. we need to work more with china. i think the problem is president trump has more of an outsourcing notion that somehow, okay, over to you, china, you sort this out. we'll support you and, by the way, stop calling you a currency

manipulator and all the other bad things you don't like. china is not going to be able to do this alone. i would keep the door open for notion, not that the north koreans have shown interest in negotiations, but having done it for years, i think it was the right way to keep our relations with japan and south korea together, and having taken a lot of criticism from people who think how can you think negotiation is the right answer? it has to be a factor in it if you're going to keep others together with you on the issue. >> brangham: former ambassador christopher hill, mark bode bowf the "atlantic" magazine, thank you very much. >> you're welcome. thank you. >> brangham: next, a legal setback for the trump administration and its effort to reverse environmental regulations from the obama presidency. yesterday, an appeals court ruled that the environmental protection agency cannot delay

implementation of a rule limiting methane emissions from new oil and gas drilling wells. the court said the e.p.a. can re-write the rule, but it can't take the short-cut of suspending enforcement. juliet eilperin is a reporter for the "washington post," and she's been covering this story. welcome back to the "newshour". >> of course, thanks. >> brangham: tell me, what did the court, in essence, rule? >> what the court said is it wouldn't necessarily stand in the way if the administration wanted to we are write an existing rule on the oil and gas industry but the administration couldn't simply suspend compliance with the rule, it had to go through laborious public comment process if it wanted to do that. >> brangham: this rule is about methane that, as you've reported and many others, that methane is particularly potent greenhouse gas, 25 times more potent than co2 is. what did the obama administration rule actually do? >> it imposed new restrictions

on oil and gas wells that are either new or modified, that if the oil and gas industry was going to create a new well or modify an existing one, it had to have tighter restrictions to lower the releases of this greenhouse gas as kind of a way that the administration was looking to reduce these emissions across the oil and gas industry over time to slow down climate change. >> brangham: e.p.a. pry administrator pruitt and many others argue to enact these rules is too expensive and that they overlap state rules governing methane. the e.p.a. argued their rule was not subject to judicial oversight which i take it the judges were not happy to read. >> yes, on a 2 to 1 ruling, it's worth noting the majority were two democratic appointees, the senator was appointed by a republican, said essentially by

doing this, by suspending the rule it's essentially revoking it altogether and that is subject to judicial rule. they also took aim that the environmental protection agency and the american petroleum institute were making that industry didn't have sufficient input into the rule and the argument was we can point out all the ways which you had to comment and the rule addressed your concerns, maybe not to your liking, but tackled the questions when they issued the rule in 2016. >> brangham: this move by the e.p.a. was one of many attempts by scott pruitt and the e.p.a. to push back on obama era regulations they don't like. does what the court ruled in this particular case have any bearing on the other attempts in other realms to roll back implications? >> this rule appears to have implication, not only for scott pruitt and the e.p.a. but the interior department, labor department, other agencies. these are are always where an

effort is underway to revoke the obama era rules and the court said, for now, the task is harder than you thought, you can't just freeze them in place and you're going to face serious obstacles in yore way because there will be folks on the outside challenging it, and we think they have merit and you need to take a different course if you're going to revisit some of these rules. >> with regards to other environmental regulations, most notably the president backed out of the paris climate accord or said the u.s. would back out of it, and i knew scott pruitt was among many arguing with that. there was a big debate within the administration, as you've reported. does this give you a sense that, barring yesterday's ruling, that scott pruitt has really become one of the more influential cabinet members insofar as his ability to do the things that the president wants done? >> absolutely. i think that folks who are a fan of what scott pruitt are doing and those who oppose him would say he's clearly emerged as one

of the most effective cabinet members. we've seen him already take action on a slew of policies. it's nearly 30 rules or major decisions that he has reversed in some ways and, so, what we're seeing, is even though he only has a handful of appointees in place at this point, he has managed to manipulate the leaders of power quite effectively in a way that certainly it is taking some of his counterparts in other departments longer to master. >> brangham: juliet eilperin of "the washington post," thank you so much. >> thank you, william. >> brangham: stay with us. coming up on the newshour: the bushmen of the kalahari desert, fighting for their ancestral lands. a new way to make beer that's all the buzz. turning national parks into classrooms. and, uncovering a creature that roamed the earth 13,000 years ago.

but first, it is growing season for farmers across the midwest, and many are faced with yet another tough financial forecast, as corn and soybean prices remain low, which means less money in farmer's pockets. in nebraska, some producers are now coming to grips with what some say is this new reality. from net in nebraska, jack williams reports. >> this is our little office that we use, kind of a break room. this is the counter, where we can work on the computer and order parts and things like that. >> reporter: on a family farm in prague, nebraska, about 40 miles north of lincoln, carl soucek is right at home. his family has been farming this land since the late 1940s. they grow mostly corn and soybeans, but the last couple of years haven't been easy. high prices for crops translated to more income for farmers a few years ago, but now, those prices have tumbled, leaving farmers in a financial ditch. >> the best thing that ever happened to the corn industry

was $7 corn, and the worst thing to happen was $7 corn, because it threw everything out of balance. i think we'll see the cycle come back. i don't know when it's going to come back. >> reporter: while he waits, soucek is doing what he can to cut costs on the farm. instead of taking his equipment to the local implement dealer for repairs, he has parts delivered to the farm and does those repairs himself. how much does that save you? doing your own repairs? if you had to take your trailer in yourself, how much would that cost you, compared to doing this yourself? >> shop rates can run anywhere from $75 to $150 an hour. and service calls? if they come out to the farm from the dealership to work on a piece of equipment, service calls could be another $250 on top of that. so if it's something we can take care of ourselves, every time we do that, we're saving a little bit of money. >> reporter: soucek doesn't

apologize for enjoying the good times a few years ago. he says farming isn't always easy, and when prices of crops such as corn and soybeans shot up, many farmers' earnings increased, and they enjoyed a higher standard of living. it was a lot different than the days when they had to watch every penny they spent. >> if we need to go back to that, we will. and i think we have already. we're careful about our family living, and so, "been there, done that" and will do it again if we need to tighten our belts that much. >> reporter: at a recent economic workshop in lincoln, farmers and ranchers got a dose of economic reality. with falling prices of corn, soybeans and wheat bringing farmers less income, many are facing more debt, tighter margins and an uncertain future. they're looking for guidance as they try to navigate through the down times without too much damage. >> they've seen the good times, they've seen the bad times. they know nothing lasts forever and they keep track of things and they monitor things and they're aware of things.

but there's probably a decent number of people out there that haven't had that perspective and are still trying to adjust to the new situation. >> reporter: economic factors, such as high land costs and skyrocketing property taxes, are testing the resolve of some midwest producers. but, that might actually be a good thing for their long-term financial health. >> tough times make better managers. and if i think about the producers i work with, those who had tough times in the '80s are great managers today because they had to learn how to make those tough choices, they had to learn how to manage their business like a business, and they continued to do that through profitable times and made a lot of money through that. >> reporter: dave nielsen is a third-generation farmer in lancaster county in eastern nebraska, where he grows corn and soybeans on about 2,000 acres. his father and grandfather worked this ground before him, so he's seen the good and bad times. he says the younger farmers who got into the business a few

years ago when prices were high are the ones who feel the downturn the most. >> it was really tough on young guys starting out then. young guys starting in those glory years, wow, this is easy. there was a lot of youth that came back to the farm-- maybe left jobs in town and came back to the family farm. you know, now it's a whole different ballgame. now, you really have to watch what you're spending on family living and that. >> reporter: nielsen probably won't lime his soil this year and like carl soucek in prague, he's doing a lot of his own repairs to save money. and, he's taking a hard look at the rest of his expenses. >> every good operation should, even in good times. really, you should. you probably just, a little sharper pen or a little sharper pencil when you're in the downturn. >> reporter: for the pbs newshour, i'm jack williams in

lincoln, nebraska. >> brangham: now, we travel to botswana in southern africa, to meet a tribe who are fighting their government to retain the right to live on their ancestral lands. they were forced off, in part, because their lands are rich with diamonds. special correspondent martin seemungal has our story. >> reporter: their clothes are modern, but their tools of the hunt are thousands of years old. the san-bushmen still use the spear, and the bow and arrow. botswana's enormous central kalahari game reserve is their home, and one of the last places on the planet where you can find bushmen who still hunt and gather to survive. the san have been tracking like this for generations. technically, it's illegal, because the government has banned hunting inside the central kalahari game reserve, but some of them do it anyway. they say it's very difficult to

stop, because it defines who they are. tolme etata's first memories are of hunting this land. "if we stop hunting, our culture would be affected," he says. "hunting and gathering is part of us." though it is part of them, it is not part of the plan for the central kalahari game reserve, as botswana's government sees it. the san-bushmen's way of life and culture are under threat. their struggle to remain here, in a place originally set aside for them in the 1960s, goes back to a major discovery in the 1980s: diamonds. by the mid-1990s, the hunt for precious stones in vast, open pit mines, like this, meant eviction from the reserve for the hunter-gatherers. mohulude moete says it was done by soldiers and military police. he says, "we were given

instructions: if you don't get into the truck, we will shoot you. some of our water containers were emptied into the ground. we had no options, so we had to go along with them or be shot." these women were young when the authorities came for them, but say the memories are unforgettable. "all the houses were destroyed. houses that they used their energies they were destroyed." >> reporter: wells were sealed up. in spite of that, small numbers refused to leave. but, there were more evictions; another big one in 2002. the government denied any connection between the evictions and diamonds in the central kalahari game reserve. it said the bushmen were being moved out to protect the wildlife in the reserve. botswana's president at the time was festus mogae. will you let the bushmen go home, mr. mogae? "where is home? home is in botswana." in c.k.g.r., will you let them go home? "no, no." are they not allowed to their ancestral land?

>> reporter: the semi-arid kalahari desert is a harsh place, but it's liveable, if you know where to gather along with the hunt. whether it's roots buried deep in the sandy soil, or wild melons worth a day's water, all of their sparse world is put to work. traditional huts comes from the desert brush. onjustice xothelo says two days's work will last a decade. the roof is a type of grassy thatch. the grass on top won't allow even water to get in. but the government wanted fewer bushmen staying in, and the evictions from this land continued for nearly ten years. bushmen were relocated to new settlements. this one is called "new xade," named for the village they were forced to leave. new xade is just 50 miles from the kalahari, but it might as well be 5,000 miles away. officially, nobody is allowed to return. over the years, some have tried

to recreate life in the villages, but they say it's just not the same. you can find those traditional huts among the small, government-built houses. "building the structures here is a reminder to us that we had these huts in kalahari," he says. "but our ancestors aren't here. we build them to remind us what we had." new xade has good roads, a modern clinic and a school. but beyond government-related jobs, there is little else; >> i'm looking for a job. >> reporter: there's nothing to do here? >> yeah, we have nothing to do. so, dying for hunger looking for job. >> reporter: there is a small mountain of beer cans outside the one building that does do big business: the local bar. alcohol abuse is rampant, leading some to criticize the government for creating these relocated towns.

survival international, an agency that works to protect indigenous people, has been the most vocal. a spokesperson with survival says, "it is clear that it is not a viable way of life. it is not based on choice. it deprives people of their meaning, their sense of well- being." survival helped the bushmen in botswana's courts, a proposition that ended up winning in 2006; the high court ruled the bushmen had been removed unfairly and should be allowed to return. but the government decided it would read the court ruling very selectively: only bushmen who'd brought the suit would be allowed to return. mosetayani matsipane was there for the court case and heard the judges' ruling, and could return. ten years later, he is the leader of mothlomelo, one of a handful of small bushmen settlements in the reserve. the government says it is working with the villages to restore some basic services,

like access to water. it also wants to focus on community-based tourism projects. matsipane's wife hakanyaziwe says this is where she belongs. matsipane is happy to be out of new xade, but he doesn't think the government's attitude has changed. he believes they still want him out of the reserve. "i continually get pressure," he says. "the government has been doing the same thing as before. but i would rather they take my dead body-- i won't go back." "what's important to me is the fruit of the land in kalahari," she says. "in the resettlement camps, everything is about money," she says. "if you don't have money, people end up stealing to survive." >> reporter: professor maitseo bolaane is the director of the san research center, a small

office at the university of botswana in gaborone. she believes the san people are a resource that can be used for the good of the kalahari reserve. >> the people themselves are monuments. they can contribute their knowledge system in the utilization of the resources within the central kalahari game reserve. >> reporter: inside the c.k.g.r., those small communities hold on, numbers dwindling every year, living in the hope that others will be able to return. for now, it is only them, dancing in the desert under the kalahari stars. for the newshour, i'm martin seemungal in the central kalahari. >> brangham: on this independence day, many americans will no doubt be enjoying a beer or two. one of the essential ingredients in beer is yeast. but for 600 years, only two species of yeast, ale yeast and lager yeast, have been used for

traditional brewing. but now, a lab in north carolina may have found a third species, and they found it in the strangest of places: on bees and wasps. newshour science producer nsikan akpan and our "sciencescope" team reveal what the buzz is all about. >> reporter: it feels like beer brewers will do anything to spice up their booze. there's pizza beer. banana split chocolate stout. beer with squid ink. and of course, rocky mountain oyster stout, which is flavored with bull testicles. all this fuss seems silly, when the foundation of alcohol's flavor is plain, old yeast. yeast, these little microbes that take sugars and ferment them into alcohol, define a beer's character. yet, for 10,000 years, beers have essentially relied on two types of bland yeast, that basically add no flavors. now, a lab in north carolina has discovered a new yeast species that produces an array of flavors without added ingredients. where'd the find it? on bees.

the story of bumblebeer begins at north carolina state university, in the lab of rob dunn. once a tropical forest ecologist, dunn now explores the jungle that surrounds us-- the one filled with bugs and microbes. >> at some point, my lab shifted to focusing more on people's daily lives, and that includes food, and it includes thinking about the biology of food. >> reporter: one day three years ago, a colleague inquired if the lab knew of any microbes in the environment capable of making beer. dunn and company instantly considered insect pollinators, like bees and wasps. here's why. yeast hang out in flower nectar, where the microbes feast on the boatloads of sugar and then produce or ferment sweet aromas, which then attract the buzzing bugs. >> we actually think, based on some work from colleagues in italy, that it's very likely that those first beers and breads were relying on yeasts

from insects, too. >> reporter: back then, a bug carrying a fermenting yeast may have fallen into some wet grain. boom, welcome to the booze cruise. in fact, some scientists argue, human agriculture started just to mass produce grains to make beer. the more beer we drink, the more yeast we have to grow. >> unambiguously the most successful organism in the world is yeast. if you think about all of the yeasts we make everywhere for many of the products we make, they won. >> reporter: so where would you even start looking for a new beer-making yeast? >> part of this is science, and part of this feels more like an art that's hard to describe. >> reporter: meet anne madden, the dunn lab's microbe wrangler. to search for unknown yeast, she started by catching a wild bee and a wild wasp. she then transferred every microbe from their bodies to a petri dish. don't fret, animal lovers-- she didn't commit mass bug-icide. >> to make bumble beer, and all

of the different bumble beers that we've made since, we've killed two bugs. you've likely killed more bugs on your way to a bar to get beer than we did in the process of making it. >> reporter: a couple days later, a forest of microbes appear on the dish, and then in four steps, madden combines her senses with technology. first, she looks to separate the yeast from bacteria or fungi. >> it's about understanding when something glistens in a certain way. >> reporter: next, she picks a handful of yeast candidates, grows them on a new dish and then follows her nose. >> you can smell the same smell, both on that plate, and in that final beer. >> reporter: her third task is running the d.n.a. from these candidates through a national database, to ensure her picks don't cause disease. >> it's almost like a google search through all other species that exist, that have been documented. >> reporter: the final step is a chemical test, because despite the long history of brewing, the genes and enzymes responsible for fermentation are largely unknown.

the survivors of this gauntlet land with john sheppard, in north carolina state's research brewhouse. >> in traditional beers that are lighter in character, like the traditional american lager, for example, you don't want to overwhelm your taste, and so what the yeast does is very important. a lot of wild yeasts-- the reason why they're not wanted is because they produce a lot of off-flavors that are not really desirable in the beer. so to get a wild yeast that doesn't produce these off- flavors can be difficult. so, we did a little testing to see whether or not the yeast strains would be able to make beer, and we selected one. it came from a wasp. because this special yeast not only makes ethanol, but makes acid, and as a result of that, we had a natural sour beer. >> reporter: the bumblebeer yeast makes other flavors-- ones that give a sweet, honey-like

taste without the addition of actual honey. craft sour beers often take months or years to make. bumblebeer yeast can do the same in a matter of weeks. local brewers have taken notice. the first suds made with bumblebeer yeast rolled out this year. until next time, i'm nsikan akpan, and this is "sciencescope," from the pbs newshour. >> brangham: you can read about how scientists are using this discovery to find more beer- producing yeasts made in the wild, on our website, www.pbs.org/newshour. >> brangham: now, on this fourth of july, with many americans spending at least part of the day outside, kavitha cardoza of our partner "education week" returns with an encore look at what students can learn in the classroom of the great outdoors. it's part of our weekly series, "making the grade."

>> nice big circle. come on in. >> reporter: fourth graders from pennycook elementary school will soon see something they have never seen before. >> so, welcome to the redwood forest, everyone. >> reporter: even though they lit in oakland, just 45 minutes away, most have never been to a national park. you might call it a sensory experience. >> aaron, can you tell us, what is another way we can observe nature? >> like, with our nose? >> with our noses. >> reporter: ranger aracely montero leads the tour. the children approach the first stand of redwoods. >> we are now inside of the magical forest of muir woods. >> oh, my god. >> everyone, take a good look up. >> whoa. >> we're now standing under one of the tallest living things in the world. >> reporter: in this classroom, students use all their senses.

>> this one feels thick. >> it feels really thick, doesn't it? >> it smells like salt. >> look up there. those are clusters of ladybugs. >> it's like a whole country of them. >> reporter: teacher darlene wong says that place-based learning, having children learn by experiencing subjects, rather than simply reading about them, teaches skills like critical thinking. >> show me your evidence. what evidence do you have to prove what you're saying or what you're writing here? >> whoa. that's so big. >> reporter: the national park service's educational programs serve approximately seven million children every year. rangers conduct teacher workshops, go on classroom visits, and, perhaps most importantly, create curriculum for these trips based on state standards. this class is learning about california habitats. >> ooh, look what i found. >> reporter: without these programs, wong says she couldn't have brought her class to the

forest. >> in terms of testing and what we have to cover in terms of curriculum and time, it's really-- it would be really hard to justify it. >> reporter: julia washburn went from junior ranger... >> it still fits. >> it still fits. >> reporter: ...to park ranger. now she oversees all educational programs for the national park service. >> it's one thing to read about a wetland, for example, in a textbook. and it's a very different thing to be standing up to your thighs in mud in a swamp or in a wetland, such as the everglades. it just really makes the learning tangible and very relevant, so students can understand why they're learning something, not just what they're learning. >> reporter: the source of the excitement? long-legged bugs called water striders. what's not as easily seen are the challenges facing the park service. budgets are down.

there's 10% fewer staff than five years ago, and the next generation of park visitors is uncertain. using national parks as classrooms isn't just about learning. it's also about growing the next generation of park visitors. >> if we don't engage young people of color right now with our parks, then, 100 years from now, we are very concerned that there won't be the celebration of the 200th anniversary of the national park service. >> reporter: grace lee heads the national park trust. they raise money for 20,000 kids to visit parks every year. >> they have been studies that have done recently that have shown, of the almost 300 million people that have gone to national parks in the last couple of years each year, that a very small percentage of them are young people, and even a smaller percentage of them are children of color. >> reporter: 50 years ago, the national park service partnered

with a.a.a. and chevrolet to reach returning world war ii veterans and their families, creating the generation of park users we see today. aging baby boomers remain the largest percentage of park visitors overall. >> what we're feeling now is that there's a new generation that is more urban, more diverse. maybe they are first-generation immigrants to the united states, first-generation citizens. maybe they came from a country that didn't have public lands or parks or a tradition of that. and so we are reaching the kids and they're bringing their parents to the parks. >> reporter: jon jarvis, the former director of the national park service, says america's parks must tell the country's evolving story. >> filling in the gaps, as i would say, in the american narrative. we have added sites for civil rights, like harriet tubman. we added stonewall, which tells the story of the l.g.b.t. civil rights movement as well.

we need to be telling that story, so that all americans feel part of the patriotic and symbolic values that this nation embodies. >> reporter: jarvis says they have also embraced technology, webcams, online chats, even video games. national park sites are actually "pokemon go" sites? >> they are. they are. the "pokemon go" community has spread these little monsters all over the national park service, and we're embracing that, because it's getting people outside and getting-- using technology in a way that sort of connects them to these places. >> whoa. >> reporter: here in the redwood forest, these 10-year-olds have found something better than "pokemon go" characters. >> turkeys. >> gobble, gobble. >> the evidence shows that when kids are exposed to the place, they learn, they retain, they become more interested and more excited about learning. >> whoa.

>> how do you feel right now? >> being in the redwood forest makes me feel happy. >> being in the redwood forest makes me want to meditate. >> being in the redwood forest makes me feel short. ( laughter ) >> reporter: the director of the park service hopes that using parks as classrooms is just the beginning. >> what i wanted to do was to say that the national park service is a contributor to american education, both for students, but for lifelong learning as well. >> reporter: for the pbs newshour and "education week," i'm kavitha cardoza, reporting from the golden gate national recreation area in california. >> brangham: continuing our national parks theme: the channel islands national park, off the coast of southern california, was the site of a recent discovery of part of a pygmy mammoth, a species of elephant that roamed the earth 13,000 years ago. students from etiwanda high

school in southern california, part of the newshour's student reporting labs, produced this report, which is narrated by rising high school senior nick hinojosa. >> reporter: off the california coast lies channel islands national park, where archaeological discoveries are still being made. laura kirn is the chief of cultural resources for the channel islands national park. >> channel islands national park is world famous for its archaeology. channel islands really represent a part of california that doesn't exist on the mainland any more. and because we don't have burrowing animals here, the archaeological record, the evidence in the ground is intact and that is unheard of. >> reporter: the preservation of the islands' archaeology has made it possible for new artifacts to be discovered, such as a mammoth skull excavated in fall 2016 on santa rosa island. monica bugbee, a preparator and archaeologist for the mammoth site in south dakota has begun the painstaking process of

removing the skull from its plaster cast. >> this is kind of an exciting discovery because pygmy mammoths, even though they're really cool-- everybody likes them because they're small, they're neat-- we actually don't know a whole lot about them. this guy was found by a park service intern who was doing a stream survey. so, they were just doing routine walk down a canyon, and they happened to notice it. >> reporter: the intern who discovered the skull, peter larramendy, was a recent college graduate who recognized the tusk sticking out of the wall could be something much more than just a rock. >> he was part of the excavation. it was something that you dream about as a child, discovering something like a dinosaur or something really exciting. >> reporter: don morris is a retired archaeologist for the national park service, who aided in the excavation of this discovery. >> i think i can confidently say this is the best skull-- pygmy mammoth skull, that's ever come off the island. certainly, it's the best one i've ever seen. this skull in particular, because it looks like it might

be in the middle of the two species, columbian and pygmy, it can give us a much better idea of how that process actually worked, you know how did they actually dwarf from columbians to pygmies. >> reporter: scientists used radiocarbon dating to discover how long ago this mammoth was alive. this kind of dating is done by measuring the amount of carbon-14 in a sample and using its half-life to calculate how old the sample is. >> there was some charcoal found in the dirt, and we radiocarbon dated that and it's about 15,000 years old, i believe, so this guy's actually pretty young. >> reporter: justin wilkins, a curator at the mammoth site, has been working with bugbee to clean and prepare the skull for display. >> so in looking at the past, we can then access how our species or other species handled changes in the environment. so we look at the mammoths, we look at humans, we also look at a bunch of small animals to see how those animals handle these changes.

and then try to decide or predict, based on the information and patterns we see from these specimens, what patterns we're seeing in the present, how that's going to change in the future. >> reporter: much of archaeology still depends on careful observation and human work. >> you've got to move dirt, you've got to keep your eyes open and pay attention to what you're observing. >> it's incredibly exciting to think that these things are still out here, they're still very fragile, and we want to protect them and study them in the right ways. but it doesn't mean that people can't still discover exciting, new things that happen to be thousands of years old on santa rosa island. >> brangham: and now to a "newshour shares:" something that caught our eye here, that may be of interest to you. when you think of the most popular sports in the world, even us americans know that soccer is number one worldwide.

but what about number two? believe it or not, it's cricket. now, that english game is starting to catch on in the united states. tina martin from pbs station wgbh in boston reports. >> reporter: suiting up, stretching out and getting in a little batting practice before a cricket match on a remote field in wrentham. it's an unusual game to most americans. it most resembles baseball, except you have a bowler instead of pitcher, and the ball has to bounce before it can be hit. games can last for hours, even days, and scores go into the hundreds. >> i am completely into it. >> reporter: nitin meweda has played since he was a boy in india. he says american co-workers were often confused about his favorite sport. >> they would say, what did you do this weekend? and i would say, i played cricket, and they would say, what's that? >> reporter: cricket was played

in the united states back in colonial times, but had pretty much died out by the civil war. but it has thrived in other parts of the world, with international matches that are among the most watched global sporting events. >> cricket in india is like religion. it has more than three times the population of the united states, and there is one sport. can you imagine if, in the states, you had one professional sport, all over the year, how crazy that would be? it is crazy. >> reporter: ravi uppalapati is >> reporter: most of the players in massachusetts are immigrants, representing far corners of the world. >> most of us are from india, but there are a lot of people from pakistan, sri lanka, australia, and england. >> reporter: ravi uppalapati is one of the organizers of the massachusetts state cricket league, the m.s.c.l.

he says they now have several thousand players. >> i think there were 12 teams in the cricket league in massachusetts in '97. there are more than 30 teams now, so things have picked up so much. >> reporter: the m.s.c.l. is trying to create a new generation of players, sponsoring clinics and camps. >> you see lacrosse now. last two to three years, no one was playing lacrosse. kids are loving lacrosse, so it's just a matter of how, we introduce, where we introduce. >> reporter: a bigger challenge might be educating the parents on what they're actually watching their kids play. for the pbs newshour, i'm tina martin in wrentham, massachusetts. u.s. secretary of state rex tillerson confirmed the missile north korea launched today was in fact an intercontinental ballistic missile. he called for stronger measures to hold north korea accountable. the u.s. military confirmed u.s. and south korean forces today carried out a military exercise to counter what they called north korea's destabilizing and unlawful actions.

on the "newshour" online right on the newshour online right now: the electric guitar has long been a symbol of american cool. why, now, is it falling in popularity? we're hosting a twitter chat on thursday at 1:00 p.m. to discuss the art of the guitar and the future of music. learn more on our website, www.pbs.org/newshour. that's the newshour for tonight. i'm william brangham. join us online, and again here tomorrow night. for all of us at the pbs newshour, thank you, and see you soon. >> major funding for the pbs newshour has been provided by: >> bnsf railway. >> the ford foundation. working with visionaries on the frontlines of social change worldwide. >> carnegie corporation of new york. supporting innovations in education, democratic engagement, and the advancement

of international peace and security. at carnegie.org. >> and with the ongoing support of these institutions and individuals. >> this program was made possible by the corporation for public broadcasting. and by contributions to your pbs station from viewers like you. thank you. captioning sponsored by newshour productions, llc captioned by media access group at wgbh access.wgbh.org >> you're watching pbs.

♪ >> it's the 4th of july in washington, d.c. more than half a million people have their eyes on the skies. they're celebrating our country's independence in the traditional way ... with fireworks! tonight, 15,000 pounds of paper balls will be hurled skyward and explode into a cacophony of color and sound. for these guys, it's like christmas, new year's and the super bowl all rolled into 20 minutes. to get here takes hours of hard