♪ Around the world, the escalating impacts of climate change are fundamentally altering our planet.

On the island nation of Japan, which is especially vulnerable to natural disasters, these changes aren't just impacting the environment.

Deeply ingrained cultural and spiritual practices that rely on nature are disappearing.

♪ I'm Gulnaz Khan.

As a journalist, I'm reporting on how climate change is endangering humanity's most sacred sites and traditions, as well as how faith-based communities around the globe are tackling this humanitarian and existential crisis with innovative solutions.

♪ [Wind blowing] ♪ Gulnaz: In the Kino Mountains, known as the Japanese Alps... Shinto priests have recorded sacred natural events.

♪ But today, this documentation is emerging as incontrovertible proof of climate change.

♪ [Kiyoshi speaking Japanese] ♪ [Drum beating] [Drum beating] [Kiyoshi speaking Japanese] ♪ ♪ [Kiyoshi chanting] [Chanting continues] ♪ Gulnaz: Shintoism has a long, rich history in Japan, but unlike many other faith traditions, it has no founder or official scripture.

♪ Japan isn't a religious culture, but it's a deeply spiritual one.

There are more than 80,000 shrines across Japan, and they receive millions of visitors every year.

♪ Spirits, deities, and ancestors, and the power they wield over the lives of humans are concepts that permeate Japanese culture.

And so people regularly visit shrines to seek blessings, protection, and guidance in their personal and communal lives.

♪ Respect for nature is also at the heart of Shinto.

All shrines are surrounded by trees because the natural world, from mountains to lakes to forests, are the dwelling places of divine spirits and Gods known as Kami.

♪ They're also considered the forces behind significant natural events.

♪ For centuries, the annual freezing of Lake Suwa inspired awe and wonder in the Japanese imagination.

This mythical phenomenon is called Omiwatari or the crossing the gods.

♪ But because of rising global temperatures, this natural wonder that has evoked the divine for almost a millennium is now on the brink of vanishing.

♪ Kyoto Ko: I'm Kyoto Ko.

I'm an author of Japanese history and culture, and folktales of Japan.

♪ So, Suwa Taisha Shrine is one of the oldest shrines in Japan, and this is where the god Takeminakata is enshrined.

He is the god that crosses Lake Suwa when it's frozen and leaves ridges of ice along the path.

So this is where the story begins.

♪ Takeminakata, he is a big, muscular, alpha god, and he lived in the north of the lake with his wife.

And one day they had a quarrel and the wife was so angry she moved to the south of the lake.

And one cold winter night, Takeminakata got very lonely, vulnerable.

He wanted to see his wife, so very late at night, he rowed his boat across the lake and had a good time with his wife.

But the next morning, before sunrise, he realized that the lake was frozen and he couldn't row his boat across.

So, he made a dash and because he's so big, he left a streak of, like, bulging ice after him.

And that's called Omiwatari or "God's Crossing," and that's supposed to occur every winter on a cold winter morning.

♪ Gulnaz: Beyond centuries of rituals, stories, and traditions, the priests at Lake Suwa have also maintained a nearly unbroken account of both Omiwatari and other meteorological events.

♪ These are some of the oldest continually kept climate records in the world.

♪ [Kiyoshi speaking Japanese] ♪ ♪ [Cracking] [Wind blowing] ♪ ♪ ♪ ♪ Gulnaz: The lengthening absence of Omiwatari is an indisputable indicator of climate change.

Such cultural losses aren't simply fading rituals of a bygone era.

They're woven into the fabric of Japan's modern identity.

♪ But the degradation of Lake Suwa in recent decades has inspired local residents to take action towards safeguarding its future.

♪ [Atsushi speaking Japanese] [Wife speaks Japanese] [Atsushi speaking Japanese] ♪ ♪ ♪ [Wife speaking Japanese] [Atsushi speaking Japanese] [Wife speaking Japanese] [Atsushi speaks Japanese] [Wife speaking Japanese] [Atsushi speaking Japanese] [Wife speaks Japanese] [Atsushi speaking Japanese] ♪ ♪ [Speaking Japanese] [Speaks Japanese] [Speaking Japanese] ♪ [Gull squawking] ♪ [Atsushi speaking Japanese] ♪ ♪ ♪ [Birds chirping] ♪ ♪ ♪ Gulnaz: A lot of us are familiar with the feeling of nostalgia, right?

It's a pretty universal human experience.

It's that sense of longing or grief when we're separated from something we love, either by distance or time.

♪ [Birds chirping] But there's another concept called solastalgia, and it captures the grief specifically caused by environmental change, as we watch the places we hold most dear degrade and disappear.

♪ This community has witnessed Omiwatari for centuries, the freezing of the lake, the crossing of the gods.

[Birds chirping] Today, they're experiencing a slow, ongoing loss.

♪ We often think of climate impacts as sudden and violent.

Wildfires, floods, storms.

This is a different kind of experience and no less devastating.

It's essentially the feeling of homesickness while still being at home.

[Birds chirping] The community doesn't know if and when Omiwatari will form again or whether their children or grandchildren will experience the same awe as their ancestors before them.

♪ For Momose and the priests of Lake Suwa, the disappearance of Omiwatari is both an omen and an admonition.

It represents the cataclysmic consequences of disharmony between humans and nature.

[Birds squawking] ♪ A hundred miles southeast of Lake Suwa, Japan's largest city is also on high alert.

♪ [Train rumbling] Greater Tokyo is home to nearly 40 million people.

[People chattering] It's not only the largest city in the world.

It also sits on a massive floodplain whose five rivers regularly overflow.

[Horn beeps] [Air hissing] Deep beneath the city, there's a vast concrete temple, the world's largest underground water diversion system.

♪ [Nobuo speaking Japanese] ♪ ♪ ♪ ♪ [Voices echoing] [Nobuo speaking Japanese] ♪ ♪ ♪ ♪ Gulnaz: In Japanese, there's a word for emotions that transcend language: yugen.

It's those indescribable experiences of awe, wonder, and mystery.

The Japanese playwright Zeami Motokiyo wrote that it's the feeling when you "Gaze after a boat that disappears behind distant islands," or when you "Wander in a huge forest without thought of return."

♪ Japan's embrace of high-tech future-proofing isn't its sole response to the threat of climate change.

It also possesses one of the most powerful nature-based solutions-- healthy forests.

♪ Woodlands cover 67% of the country, from its highest mountains down to the sea.

♪ For centuries, forests have been places of pilgrimage and veneration, a connection between the earthly and spiritual realms.

♪ But today, Japan's forests lack the biodiversity necessary for effective carbon capture or climate resilience.

♪ Many of them are fast-growing, shallow-rooted cedar and cyprus monocultures that are vulnerable to landslides, pests, and other climate impacts.

♪ Remarkably, Shinto shrine forests, or chinju-no-mori, represent some of the few remaining native forests in Japan and hold a uniquely powerful climate solution in their roots.

♪ [Wind blowing] [Ayako speaking Japanese] [Bells jingling] ♪ [Bells jingle] [Kiyokazu speaking Japanese] ♪ ♪ [Ayako speaking Japanese] ♪ ♪ [Kiyokazu speaking Japanese] ♪ [Kiyokazu speaking Japanese] [Ayako speaking Japanese] Gulnaz: 30 years ago, Ayako Ishimura and Kiyokazu Kusayama were students of the celebrated botanist and plant ecologist Dr.

Akira Miyawaki.

It was Dr.

Miyawaki who first recognized that chinju-no-mori, or shrine forests, were the key to a simple but revolutionary approach to soil and forest regeneration.

♪ [Ayako speaking Japanese] ♪ [Kiyokazu speaking Japanese] ♪ [Ayako speaking Japanese] ♪ [Birds chirping] ♪ [Kiyokazu speaking Japanese] ♪ ♪ ♪ Gulnaz: Faith leaders like Mr.

Kusayama play a profound role in shaping community values and behaviors.

At its heart, the Izumo Taisha Shrine is a place of connection.

People from all over the country come here specifically to pray for relationships-- for marriage, for love, or for their future soulmate.

Mr.

Kusayama's tree-planting efforts extend these bonds to embrace the natural world.

His work reinforces the idea that, just as we're connected to each other, we're deeply connected to nature, and our collective wellbeing depends on honoring that sacred bond.

♪ Dr.

Miyawaki's method for planting rapidly growing, biodiverse forests caught the attention of faith leaders across Japan, and not only from the Shinto tradition... ♪ [Birds chirping] [Hioki speaking Japanese] ♪ ♪ ♪ ♪ [Birds chirping] ♪ [Bells chiming] [Hioki chanting] [Bowl ringing] [Hioki chanting] [Bowl ringing] [Hioki chanting] [Bowl ringing] [Hioki chanting] [Bowl ringing] [Drum beating] [Birds chirping] ♪ [Hioki speaking Japanese] ♪ ♪ ♪ [Rumbling] ♪ [Water rushing] ♪ [Hioki speaking Japanese] ♪ ♪ ♪ [Man speaking Japanese] [Hioki speaking English] ♪ ♪ Gulnaz: In the aftermath of the costliest natural disaster in recorded world history, Hioki Doryu and Dr.

Miyawaki came to realize that his protective forests weren't just useful in fighting climate change.

They could also mitigate the worst effects of natural disasters.

♪ 20 years ago, Mio Urata learned about the Miyawaki method and has been planting forests ever since.

♪ Mio: The aim of the Miywaki method is to create a natural forest, a very biodiverse natural forest.

We make a multi-layered forest, and a multi-layered forest would consist of canopy trees, sub-canopy trees, and shrubs.

And first, this is a tree that would make up the canopy.

This is called Tabunoki in Japanese.

It's the tree that Dr.

Miyawaki loved the most.

This is a camellia, Camellia japonica, and it's in the sub-canopy layer.

It grows to maybe about 20 meters high.

This is the Masaki tree.

It is the shrub layer.

Very strong tree and grows everywhere.

♪ Gulnaz: In addition to a diversity of species, Miyawaki forests are, by design, planted very densely.

As trees compete for water and sunlight, this leads to extremely fast growth rates.

♪ Mio: A Miyawaki forest grows, like, one meter a year, and so this is a forest that's one year old.

And over here you can see a forest that's four years old.

So there's quite a difference here.

♪ Compared to a traditional forest, a Miyawaki Forest grows about ten times faster.

For example, a natural forest would take about 200 years, 300 years to mature, whereas a Miyawaki forest would take about 20 years or 30 years.

♪ [Volunteer speaking Japanese] [Makoto speaking Japanese] [Makoto speaking Japanese] ♪ [Makoto speaking Japanese] ♪ [Volunteers chattering] [Makoto speaking Japanese] ♪ ♪ ♪ ♪ ♪ Gulnaz: After the 2011 tsunami, there was a rush to protect vulnerable coastal communities by constructing massive concrete sea walls.

♪ Tens of billions of dollars were spent on hundreds of miles of barriers.

♪ But while concrete may have the upper hand in the short term, when it comes to sustainable climate resilience, green sea walls are superior.

♪ [Thunder] ♪ The fishing town of Kesennuma was one of the hardest hit by the disaster.

♪ Here, the ruins of the local high school remain unchanged.

♪ A reminder of what it means to coexist alongside unpredictable forces.

♪ Despite the trauma its people endured, the community of Kesennuma opted for a future without concrete walls.

♪ [Makoto speaking Japanese] ♪ Gulnaz: When the people of Kesennuma decided against the construction of a tide barrier, they did so based on their deep understanding of the local interconnected environment.

For generations, they've studied the precise conditions under which life flourishes, which is why they planted tens of thousands of trees in the mountains that line the rivers feeding into Kesennuma Bay.

♪ [Makoto speaking Japanese] ♪ [Boat motor rumbling] ♪ [Masanori speaking Japanese] ♪ ♪ ♪ [Makoto speaking Japanese] ♪ Gulnaz: The oyster farmers of Kesennuma thought they'd lost everything in the 2011 tsunami, but their farms recovered remarkably quickly.

♪ Scientists determined that the nutrient-rich forest that they'd planted made the marine ecosystem more resilient to natural disasters.

It was a testament to the importance of local knowledge in implementing successful climate solutions.

[Masanori speaking Japanese] [Motor whirring] [Makoto speaking Japanese] [Gulls squawking] [Masanori speaking Japanese] ♪ Gulnaz: Over the next century, our planet will witness a sustained period of sea-level rise unparalleled in the history of human civilization.

♪ Extreme weather will batter small coastal villages and flood mega cities.

♪ Tsunamis, alongside rising oceans, will increase in height.

♪ As the world invests in scalable solutions, Japan's Shinto shrine forests, the dwellings of the divine, offer a vital nature-based solution.

From their carbon capture potential to their role in coastal protection and nurturing oceans, forests are a talisman against a fearsome future.

♪ Dr.

Miyawaki was involved in planting more than 40 million native trees at over 1,700 sites across the globe.

♪ The beautiful thing about these forests is that anyone anywhere in the world can plant one of their own.

You don't need to be a scientist or engineer or billionaire to be part of the solution.

♪ Protecting and restoring nature remains one of our greatest hopes for the future and for the survival of our most sacred sites.

♪ Will the next generation of priests at Lake Suwa ever witness the Omiwatari?

Will the gods cross the frozen lake once again?

♪ [Kiyoshi speaking Japanese] ♪ ♪ This program is available with PBS Passport and on Amazon Prime Video ♪