Porter Fox is the author of The Last Winter: The Scientists, Adventurers, Journeymen, and Mavericks Trying to Save the World, from which this story has been adapted.

Kulusuk, Greenland CNN  — 

Twelve Greenlandic huskies toil against a 40-mile-per-hour headwind, as box store-size icebergs and rugged 10,000-foot peaks slide past. They are as inspiring as they are terrifying — until my ski goggles ice-over, blinding me for hours.

I’ve been sitting on the back of a dogsled for three hours now, nestled between a bag of frozen seal blubber, a rifle and three duffel bags as we cruise over the second largest ice mass in the world. Two sleds behind us carry more passengers from Pirhuk Greenland Mountain Guides’ annual dogsled expedition into the Arctic Circle. The trip began in the morning, on the outskirts of Kulusuk, a small island on Greenland’s remote southeast coast. Discussion then revolved around what had been an unusually warm winter and whether or not the sea ice would be thick enough to sled over. Most of our journey would be on fjords and bays, and if the ice didn’t freeze solid we would likely have to turn back.

Sitting on the back of the sled, it’s hard to believe that anything in the world is not frozen solid. But I know better. Greenland is the last leg of a 10,000-mile tour I’ve taken of the Northern Hemisphere’s snow line, documenting how climate change has melted snow and ice.

In most parts, winter isn’t coming. It’s going.

Unlike Antarctica, where melt rates depend on the stability of floating ice shelves, the issue in Greenland includes surface melt. Warmer air temperatures melt the ice from above, then meltwater percolates through the ice to the sliding bed, lubricating its base and quickening its descent into the ocean.

On the first leg of my world tour, snow scientists in Oregon told me that a million-square miles of spring snowpack in the Northern Hemisphere had disappeared — in just the last 50 years. Others, in Washington’s North Cascades, explained how the length of winter was projected to decline across the US, in some locations by more than 50% by 2050 and by 80% by 2090. Spring snowpack depths across the country are forecast to drop during the same period by 25 to 100 percent, likely closing all but a handful of ski areas in the US. The lack of winter snowpack — and its spring melt runoff — will also become a primary driver of Western forest fires.

After a life of skiing and exploring sub-zero climes, the thought of brown summits in the Cascades, Sierras, Rockies and Alps for much of the winter was shocking to me. What surprised even scientists were statistics like the fact that, for the first time in history, nearly every glacier in world was receding — and now melting twice as fast as they were in 2000. The Alps lost half their glacial ice since the 1800s, and most of what remains will likely be gone by the end of the century. A recent report about the “Doomsday” Thwaites Glacier in Antarctica suggests that the ice shelf holding it back could shatter within five years — potentially raising sea level by two feet and flooding coastal cities like New York City, Mumbai, Tokyo and Shanghai. Further proof of how greenhouse gas emissions are indelibly altering our planet: so much ice has melted from the poles in just the last few decades that the rotational axis of the earth has changed.

Greenlanders run their dogs in a fan formation instead of the neat pairs Alaskan mushers use. The fan allows Greenland dogs to spread their weight out on thin sea ice.

The situation in Greenland is equally dire. Scientists here recently revealed that the 660,000-square-mile ice sheet had melted beyond the point of no return. If it melts completely, sea levels will rise more than 20 feet, inundating every coastline in the world.

The revelation did not seem to concern our Inuit sled drivers. It was still pretty cold on the world’s largest island. Two were brothers, Justus and Mugu. The third was a 28-year-old named Mikael, who had just won a regional dogsled competition the day before. Their ancestors had sledded across the ice for thousands of years: foraging in the most inhospitable climate on Earth. The brothers occasionally stopped to test the thickness of the ice with 5-foot long ice picks. The bay we were crossing right then had been open water three weeks ago. If the cold continued and the ice held, Justus said, we would make a beeline north toward a remote, rarely seen swatch of ice, rock and snow Greenlanders call tunu, or “the land out back.”

To envision just how much ice the planet has lost, consider that the tallest, coldest peaks in the world — the Himalayas — are losing 8 billion tons of ice a year. The Juneau Icefield in Alaska — where I visited the Juneau Icefield Research Program — will lose 60% of its mass in the next 80 years. (The icefield is about the size of Rhode Island.) In Greenland, the ice sheet lost the equivalent of an Olympic-size swimming pool of ice every second in the mid-1990s. In 2020, scientists found that number had increased ninefold, to 234 billion tons per year.

Downtown Kulusuk, Greenland, where winter now starts several weeks later and ends sooner. Nearby, one of the fastest- moving glaciers in the world, the Helheim Glacier, flows at more than 70 feet a day, dumping millions of tons of ice into the ocean.

The cascading effects of the Great Melt are stunning — existential even. As the fragile, reflective shell of snow on our planet melts, dark land and water beneath it absorb up to 80% more heat. As 9 million square miles of permafrost begins to thaw in the Arctic, more than a billion tons of greenhouse gases frozen in it will soon be released, potentially warming the planet many times more than humans have. Two-thirds of present sea level rise comes from melting ice, endangering more than 680 million people living in low-lying coastal zones around the globe. Lastly, 78 frozen water towers — like the Alps, Himalayas, and Rockies — provide the primary source of drinking water for 2 billion people. All of them will soon be gone, with few plans to replace the water supply.

In Greenland, winter now starts several weeks later and ends sooner. One of the fastest-moving glaciers in the world, the Helheim Glacier, now more than 70 feet a day, dumping millions of tons of ice into the ocean. (Visitors who hike in or visit by boat can watch it slide by before their eyes.) To the north, the Kangerlussuaq Glacier retreated three miles in just two years, between 2016 and 2018.

We are 200 miles south of the Kangerlussuaq Glacier when we finally pull into camp. Our guide, Rich Manterfield, lights a diesel furnace in the insulated hut and boils water for dehydrated meals. Outside, the dogs chow on seal blubber and settle down in the snow for a nap. Manterfield hands me a box full of flares as I wander outside for a hike. “If you see a polar bear,” he says. “Fire one at it.” It’s a pack of five. Three are missing.

I scramble up a ridge for an hour and watch the sky fade to blue as a storm dissipates. Sea ice to the east holds its blue hue as well, as do the clouds and swirling snow. The ground is rubble, broken stone sprinkled with windblown snow. The landscape looks so much like moon-landing pictures I have seen, that with my down suit and goggles on, I fell as if I have landed on another planet. It’s an alien setting, like many I have witnessed across my tour of the cryosphere. It’s a glimpse of the planet and its story, separate from our comparatively minuscule time here.

Winter has vanished from Earth before. Natural events, like volcanic eruptions, methane releases and meteor strikes created a “hothouse Earth” climate 3 million years ago, when palm trees, giant beavers and camels lived quite happily in the Arctic. The difference between now and then is that natural climate events typically took thousands of years to play out. The speed of current climate change has been seen only a few times in the past, and there will be little time to adapt. To complicate all of this, humans have oriented themselves, placed our cities, established our diet and agricultural practices rigidly within the parameters of the current climate — which could be radically different in just a few decades.

Washington's Cascade Mountains will likely see 25% less snowpack in the next thirty years and 75% less in 80 years if emissions continue unchecked.

One example close to home: up to 75% of the water used by farms and cities in the American West comes from snowmelt. The Colorado River, which is filled primarily with snowmelt from the Rocky Mountains, is losing almost 10% of its flow with every increase of 1.8 degrees Fahrenheit, creating historic water shortages downstream. The Colorado supplies 40 million people with freshwater, including those in the cities of Los Angeles, San Diego, Phoenix, Tucson, Denver, Salt Lake City, and Albuquerque. (Recently, Lake Meade, the largest reservoir in the US and part of the Colorado River watershed, hit its lowest level since it was being filled in the 1930s.)

There is no shortage of snow when we wake up the next day. The sun is already a few degrees above the peaks at six in the morning — hovering and milky, lighting but not yet warming the Arctic landscape. As if on cue, one of Mugu’s dogs climbs a large boulder and, silhouetted by the post-dawn solar explosion, arches its back and lets out a chilling howl.

Michaela King, who I met at the Juneau Icefield Research Program, was the lead author of a 2020 study that showed how the Greenland Ice Sheet had passed a point of no return. Glaciers were sliding into the ocean faster than snowfall  could  replenish them — which meant another of the planet's nine tipping points had fallen.

After coffee and more dehydrated meals, we are off again — six flatlanders, one guide, three sled drivers, and three dozen dogs steaming north. The wind has wiped the ice clean, and we cruise at 10 miles an hour all morning. The dogs intuitively know the way, tracking the headlands, following inlets, cutting around open water and ice bulges that would flip the sled.

Three hours later, we pull into the next camp, which consists of a red shack the size of a small bathroom. There are four bunks inside, three of which, we are told, will be occupied by the drivers. They need their sleep and, amusingly, don’t like to sleep in the cold.

We dig tent platforms outside in the snow while the drivers anchor dog chains in a line behind us, ostensibly to discourage curious polar bears. After a quick dinner of dehydrated “Chili Con Carne” and “Posh Pork and Beans,” I climb into my sleeping bag and unzip the door of the tent to watch for northern lights. They appear a few minutes later as a braided rope of green light, waving in the sky from the northeastern horizon to the southwest. To Inuits, light is magic. Half a sun dog indicates that death is coming for someone. If a rainbow has steep sides, it means good fortune is on the way. If the arc is flat, a disaster will ensue. The northern lights are considered an aid to shamans, who can beckon them closer or spit at them and make them meld together.

Light is magic on Greenland. Half a sun dog indicates that a death is coming. If a rainbow has steep sides, it means good fortune is on the way. If the arc is flat, a disaster will ensue. Falling meteors are excrement from the stars. Shamans are filled with light from spirits that enter through their navel and live in the breast cavity. They are bright inside; everyone else is dark so that the spirits do not notice them.

It all seems possible, watching the show. What else could explain this? Gusts of electrons and protons spinning off the sun, blowing through space like a rain squall, colliding with oxygen and nitrogen in the atmosphere. I watch the show until the freezing air — minus-20 degrees Fahrenheit at that point — burns my face. My eyelashes are frosted over and the thin, nylon sleeping bag exterior crackles as I move. Green-blue light from the sky makes the tent glow. This is the un-night of the Arctic. We are perched at the top of the world, seemingly a few yards from space — the weather, the stars, the sun, the moon. It is part of what I love about winter, the rawness of it, its irrefutability, how it takes some skill to survive. It is pure nature, with few humans to spoil it.

After a night’s sleep, we are near the turnaround point of the trip. One more camp and we will start heading back. The landscape we cover in the afternoon is different. There are no signs of life anywhere — no wind or color or sound of any kind. The ice has held, and we’ve made it to tunu — pure Arctic wilderness.

I think of all the days I have spent in the cold this year — hiking across glaciers, skiing in neck-deep powder, climbing remote mountains. I no longer see these snowscapes as individual places. Rather, they are knitted together in a white, protective blanket, insulating the stable climate human civilization had blossomed in.

We spend a final night at camp, and in the morning we begin the journey home. On the ride, I think about how there is still time to conserve winter in the north, save snow on the highest peaks, and in the process, save billions of lives from being overwhelmed by sea-level rise, drought, fire and famine. For a few more years, our fate is in our hands. After that, who knows.

Sled makers import entire trees from Denmark — there are only a handful of forests on Greenland — to use for runners and a frame. The frame has to be perfectly symmetrical, or it will break up on the incredibly rough and icy ground. (Sleds are built to flex; drivers use dental floss to stitch the nylon strapping that holds them together.) In the mountains, Greenland sleds are shorter, to maneuver tight turns. In the north, they are longer to cross sea ice without breaking through.

The expedition plays out in high-speed reverse that day: the maze of inlets, box-store icebergs, red hut, yellow hut, then the stubbled outline of Kulusuk. We pull in at sundown, and a few of the drivers’ children run out to meet us. It takes Justus about a minute to get our stuff off his sled and take off toward home. We move a bit slower, dragging our gear up the steps to the lodge, cracking the door, and practically falling into the comfort of the gear room.

It is warm and dry in here. A diesel furnace flickers in the corner of the living room. Everything looks soft. It is so-called “civilization,” the comforts of home that humanity has engineered over the last century and a half. At what cost, I wonder. We will soon see.