Narwhals are moonlighting as climate scientists.

A 91year-old pulled off a jaw-dropping agedefying feet in an ambulance powered by sunshine.

Rise up sunshine.

I'm Koi Wire.

10 minutes big world.

Let's get you your news.

We begin in London with some uplifting health news that really is a breath of fresh air.

A new study suggests the British capital's efforts to cut vehicle pollution in recent years may be helping children's lungs grow healthier.

Researchers focused on the city's ultra low emission zone introduced in central London in 2019.

Drivers of vehicles that don't meet strict emission standards have to pay a daily charge.

The idea being to put the brakes on tailpipe pollution.

The study tracked thousands of kids in London and nearby Luton over several years.

Before the clean air zone began, London's kids had higher exposure to traffic pollution and lower average lung function.

But over the next four years, between 2018 and 2022, researchers observed a 5% drop in children with clinically impaired lung function in London.

In Luton, which didn't have a clean air zone, but did make other changes like adding bike paths and lowering speed limits, the rate fell 2%.

Researchers say this is the first evidence that clean air zones may actually help child development.

That matters because lungs do most of their growing while we're young.

If they don't fully develop by early adulthood, the risk rises later in life for conditions including asthma, emphyma, and chronic bronchitis.

So, this isn't just about cleaner air today.

It could mean healthier lungs for decades.

Now to Nepal where nearly a week after catastrophic flooding tore through Himalayan communities, the search for the missing is becoming a race against both time and terrain.

As of this taping, more than 12,200 people have died.

Nearly 4,000 are still missing.

Relief organizations are helping more than 80,000 residents who've been displaced.

The United Nations says some of the hardest hit areas are still unable to even be contacted.

Rescue crews are navigating destroyed roads, unstable mountain sides while families wait for answers.

And in a place where some communities can only be reached from the sky, helicopter crews have become a lifeline.

Our Anderson Cooper caught up with one trailblazing pilot helping lead that mission.

Nepal's first female helicopter captain, Captain Priya Adekari.

>> It's a small place where so many people went missing.

It's extraordinary that you I mean the the valley is is so close and you are flying through this.

It's extraordinary.

>> Just imagine 20 helicopters flying on that valley.

Yeah.

Continuously talking with each other.

That is actually a little bit of pressure to to navigate and to radio at the same time and to know where who is doing where and we going to the same place evacuating from the same place like five or six helicopters landing.

So we need to talk with each other so frequently.

Yeah.

That is actually it.

>> And now I mean you are landing in places where the ground is like liquid cement.

>> Some of the places you have to be very careful because the helicopter might sink in.

>> It looks from the air I imagine like to a to a novice it looks like oh it's solid ground.

It's concrete.

>> No it's not concrete.

This thing that happened it's bigger than the earthquake we had in 2015.

>> Um in during the earthquake time it was in in the different places of the Kathmandu war in Nepal.

This is like in a small valley where so many people have lost life but they >> the smile I have is for the survivors.

I don't know how they survived.

Every time I go in land I see people around.

I'm like waving at them and saying like you survived.

You know the rescues that I'm doing people lying down inside my helicopter trying to open their eyes.

I smile at them and say like you survived.

>> Pop quiz hot shot.

A narwhal's famous tusk is made up of what?

bone, ivory, keratin, or pixie dust.

If you said ivory, you can toot your own horn.

Narwhal tus are actually overgrown teeth.

Did you know?

And they can grow up to 10 ft long and contain more than 10 million nerve endings.

Narwhals are known as the unicorns of the sea.

But scientists are discovering they may also make pretty incredible oceanographers.

These elusive Arctic whales are helping scientists collect data on the crucial ocean currents of a remote and hard to study corner of the planet, the rugged coast of East Greenland.

Scientists fitted six narwhals with satellite transmitting sensors and tracked them for three years as they recorded things like water temperature and salinity in remote Greenland fjords.

And the data are helping scientists better understand something called Atlantification.

That's when warmer, saltier Atlantic water pushes farther into Arctic waters.

And that matters because warmer ocean water can accelerate the melting of glaciers, which then contributes to rising sea levels.

Scientists hope this new data will help them better understand the planet's ice sheet.

If anybody tells you you're too old to chase a big dream, let's introduce them to Greybeard.

Dale Sanders is 91 years old, and he just became the oldest person ever to complete the entire Appalachin Trail.

That's roughly 2200 miles stretching from Georgia all the way to Maine.

He began his journey last September and finished at top Maine's highest mountain, Mount Kataden on Monday.

This wasn't Sanders first attempt at the trail.

>> There is a huge, huge difference between hiking the trail at 82 years old and at 91.

Huge difference.

But it is possible cuz I'm proving that >> it is a dangerous hike.

Sanders says he fell 71 times.

One fall sent him to the hospital, but Greybeard kept going.

I had a chance to learn more about this trail on my own hike.

Check this one out.

>> It kills you physically, and you're not sleeping well and you're getting bit by bugs, ripped open feet.

You just keep hiking through it.

>> Hiking like this for 6 hours would be a tall task for most.

But then there are people who hike this thing for 6 months.

That's just mindblowing.

You see this white blaze, you know you're on track.

>> That white blaze is the iconic marking of the Appalachian Trail, and it guides hikers along this 2,000mi contiguous footpath running from Springer Mountain, Georgia, to Maine's Mount Kataden.

I've hiked only a tiny sliver of it today.

>> But I want to know more about the trail and the unique individuals like Matt, trail name Road Soda, who drop everything to conquer it.

You do start to think like, why am I still doing this?

>> At hikers spend most nights in tents, but hostiles like this allow them to rest up and reconnect.

>> You have traies out here.

It's a trail family and usually just formed by the people that are doing the same miles as you couple nights in a row.

That's kind of how you create friends.

>> I love this man.

>> You don't see him for a couple days and then when you see him again, it's like you found your long lost friend again.

You develop bonds through shared adversity.

That's just it's pretty incredible.

>> Throughhikers suffer through freezing cold, searing heat, rain, wind, loneliness, exhaustion, and lots of pain.

>> It's a lovely shade of lilac.

>> A little ibuprofen.

The KG tape actually helped a lot.

>> My knees have hurt pretty much the entire time.

>> Three out of four throughhikers don't even make it to Maine.

But those who push through the pain discover joy, pride, and maybe a new outlook on their planet and fellow humans.

>> There's this like really, really strong community.

>> Everybody's so on your side all the time.

>> Every memory resurfaces out here cuz you just have so much time and you just look out and just see how beautiful our planet is from a different angle.

>> There is hope.

>> 4 months after we met him, Road Soda and his traile finally reached the top of Mount Katag.

>> Oh my god.

The end of one journey and perhaps the beginning of another.

>> As rough as this can be, I don't want to leave this life behind.

>> Today's story getting a 10 out of 10.

An ambulance that runs on sunshine connecting healthc care with communities in Kenya.

A team of 23 Dutch students called Solar Team Einhovven tested a prototype solarp powered medical clinic named Stella Juva.

The vehicle carries equipment that can include ultrasound machines, portable X-rays, and other basic diagnostic tools to rural communities far from health facilities and unreliable electricity.

The vehicle drove more than 800 km, about 500 miles through Kenya.

The student team says the prototype navigated rough roads and unpaved roads successfully.

So from testing in Kenya, we gathered that Stella is able to handle off-road terrain and being able to drive up to hundreds of kilometers.

What we also gathered is that Stella gathers more energy from the sun than it uses with all its medical equipment on board, meaning that we can deliver continuous healthcare.

The nearly 3,000lb vehicle is said to be an early demonstration project with more testing ahead.

But for communities with a lack of access to health care, this solar-p powered ambulance could be a link to a brighter future.

Students looked at a problem.

Instead of saying somebody should fix that, they started building something.

That is what we call a 10 out of 10.

All right, superstars.

It is shout out time.

This one goes to Mrs.

Devoid at Murray Middle School in Wilmington, North Carolina, who sent this incredible collection of art and cards and messages.

Hi, Dora.

Uh yeah, this one that's that's that's that's upside down, but that's me.

Thank you guys so much for making us a part of your day.

You made our day.

Stay curious, stay kind, shine on, sunshine.

I'm Koi Wire, and we are CNN 10.