For a century and a half, melting snow and ice have been the most recognizable visual evidence of climate change. You can see it in the Arctic Ocean, where the first ice-free summer in two and a half million years is predicted by 2035; in the Alps, where half of the range’s iconic glacial ice has vanished; and in the Rockies, Great Lakes and even Northeastern backyards—which were once layered with snow all winter long but now show bare earth throughout the dark months.
Even now, at this late stage in the warming crisis, the unambiguous message that the Great Melt is sending is being obscured. The resulting delay in human action has delivered a new threat: if decisive action is not taken immediately, this harbinger of climate change will morph into the first colossal domino in a cascade of natural disasters—all of which will alter life and civilization as we know it.
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If the end of our world is to come, it will likely come by way of nine natural tipping points. Climatologists say that each, if crossed, would likely result in unstoppable, runaway climate change—taking the future of the planet out of human hands. Five of these thresholds depend on the cryosphere, or frozen regions where water exists as a solid: 1) boreal forest dieback, fueled by historically low spring snowpack; 2) rising sea levels, two thirds of which derives from melting and calving ice; 3) nine million square miles of methane-rich Arctic permafrost, that, if thawed, could release more greenhouse gases than humans ever did; 4) the melting Antarctic and Greenland ice sheets that could raise sea levels more than 200 feet; and 5) meltwater from those sheets that could slow or shut down major ocean currents like the Gulf Stream, sending northern Europe into an ice age and transforming parts of the Middle East and Asia into a desert.
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To envision just how much ice the planet has lost, and how it is indelibly altering our planet, consider this: melt on the poles in just the past few decades has changed the planet’s rotational axis. I grew up in ice and snow in northern Maine, where ice fisherman parked their cars on frozen lakes in the winter and you could walk across fjords and bays from Christmas to Easter. We skied madly in the dark months—there wasn’t much else to do—and I went on to climb and ski icy peaks on five continents over the next two decades. I remember seeing a column of steam shooting up from the Amazon Rainforest on the northeastern flank of a 15,000-foot Bolivian peak that we skied a first descent on. In the Himalayas, we toured for weeks through exotic snowscapes, stopping on the summit of the 16,000-foot headwaters of the Yamunotri River—to witness the first trickles of meltwater that would soon become the Ganges largest tributary.
Large-scale melting was just getting going then; now, for the first time in recent history, every glacier in the world is in full retreat. With many of the icy slopes I skied when I was younger nearly gone, or close to it, I embarked last year on a 10,000-mile tour of the Northern Hemisphere’s snow line. I wanted to see the snowscapes one last time and document the ensuing cataclysm that the melting cryosphere will trigger.
The journey began in the Pacific Northwest, where I walked through obsidian burned forests with scientists studying how a lack of spring snowpack, and thus nourishing spring and summer runoff, had become a primary driver of the spike in western U.S. wildfires. A week later, after another historic fire ignited in California, I met Dr. Jon Riedel who created the first glacial mass balance record in the Cascades back in the 1990s—now a vital record of this soon-to-be-gone ancient ice that scientists use as a baseline to predict, among other things, outcomes of future global warming. Standing in Riedel’s house, beneath a glacial scene he’d carved into a threshold, he pointed toward the glacially fed Skagit River—that feeds forests, lakes, salmon populations, ecosystems, and the Skagit County water district. Since 1959, it has lost more than forty-two billion gallons of annual runoff as ice masses upstream dwindle. Worldwide, Riedel added, two billion people will soon lose their primary source of drinking water as eight “frozen water towers” clinging to mountain ranges around the world melt out.
In Juneau, Alaska, I discovered the legacy of the now-deceased cryo-visionary, Maynard Malcolm Miller, who invented modern field glaciology and interpreted the first whisperings of climate change in 1946 from Alaska’s shrinking ice sheets. “M3” was twenty-three years old then. Today, his legacy continues at the Juneau Icefield Research Project, the second oldest polar research station in the world, which he founded in 1946. I walked with seventy-five scientists and students on the dying icefield through what I can only describe as the “frozen oceans of the north,” as Mary Shelley wrote in her cryospheric novel Frankenstein. Two hundred-foot tall ripples of ice flowed from the peaks like rivers, bending around summits and eddying behind ridge lines and arêtes.
I visited an ice core drilling operation one afternoon—where students examined crystals that fell as snow in some of the same storms that pummeled the 17th century Jamestown and Providence colonies. By comparing carbon content in ancient air with the known temperature of the period, researchers can pinpoint the effect greenhouse gases have on climate change going back nearly a million years. Other signatures include ash from climate-altering volcanic eruptions, dust, pollen, sea salt, and traces of lead from Roman mints that corresponds to the rise and fall of the Empire. Ice core records are so vital to predicting future climates and plotting a way forward for humanity that researchers are racing to harvest samples from ice masses around the planet before they vanish.
You don’t have to travel around the world to see the effect that melting snow and ice have on our lives. Most people living in mid-latitude regions can see it out their back door. More than a million square miles of spring snow cover has vanished from the Northern Hemisphere since the 1970s. Between 1972 and 2015 in North America, snow-covered terrain has diminished by thirty-three hundred square miles per year, and high-elevation snowpacks in the western United States between 1982 and 2016 have decreased by 41 percent—an area the size of South Carolina.
Up to 75 percent of the water used by farms and cities in the West comes from snowmelt. The Colorado River, which is filled primarily with meltwater from the Rocky Mountains, is losing almost ten percent of its flow with every increase of 1.8 degrees Fahrenheit, creating historic water shortages downstream. The Colorado supplies forty 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 U.S. and part of the Colorado River watershed, hit its lowest level since it was being filled in the 1930s.
Several friends and I skied through Italian Alps to see the last living glacier there—the great Marmolada, that has been visible from the streets of Venice for thousands of years and that will be gone in a decade or two. (Leonardo da Vinci studied glaciers near the Marmolada and made sketches of how water fell from them.) Parts of the Alps are warming at three times the global average, and ski resorts there often have to transport guests to the bottom of the hill midwinter—over exposed grass, wildflowers and dirt. Villages at the foot of the mountains now live in constant fear of the peaks literally falling apart—as permafrost binding much of the range together thaws.
A delicate balancing act has played out between ice, snow, ocean and climate over the last few hundred million years. When the planet warms, reflective snow and ice melt, allowing solar radiation to be absorbed, radically increasing warming. During cold trends, the white, reflective surface expands, cooling the earth significantly and locking up much of the planet’s freshwater in miles-deep ice sheets. The effect on human civilization has been dramatic. It even altered the evolution of our species when Africa’s Rift Valley dried up during a cold era and homo sapiens were forced to adapt to arid conditions and hunt as a group. A similar cooling event 15,000 years ago dried out ancient Mesopotamia, forcing nomads to work together, settle down and create sedentary irrigated farms. Just a few centuries ago, another cooling event called the Little Ice Age sparked famine, war, disease, drought and political upheaval in Europe for four centuries—reducing some nations’ populations by half and cutting the average height of Europeans by an inch. To put this in context of current global warming: the average temperature change during the Little Ice Age was one degree Celsius.
We often think about global warming as slow and incremental, but I learned in Greenland, on the final leg of my journey, that this is not always the case. I spent a week dogsledding up the remote east coast of the largest island on earth with a group of Inuit seal hunters. The hunters grew up sledding the frozen fjords and bays around their village in the winter. In a matter of decades, many of those waterways are now ice-free all year long, cutting off hunters and entire villages from their livelihoods and food supply. Another example of the speed and ferocity of the melting cryosphere that I learned in Greenland: So much ice is melting from the ice sheet that scientists think fresh water—that is heavier than salt water—is slowing major ocean currents, including the Gulf Stream. This happened once before, as the last ice age thawed. During the Younger Dryas period, the Gulf Stream slowed significantly and temperatures in Europe dropped eighteen degrees Fahrenheit in less than a century, sending the region back into an Ice Age for thirteen hundred years.
A month before, I had met a leading Greenland researcher, Dr. Koni Steffen, who founded one of the first glacial research stations on the ice sheet, at his office in Zurich. A bundled-up Nancy Pelosi, Al Gore, Anderson Cooper, Hillary Clinton and many heads of state had made a chilly visit to “Swiss Camp,” but now Dr. Steffen was afraid that an expanding web of crevasses was going to swallow it. We spoke about glaciers in the Alps and how farms, villages and Europe’s vast hydroelectric network would adapt. He reminded me that Europe is a wealthy region and is way ahead, in terms of adaptation, of many parts of the world. It is the developing world that will feel the real pain of the melting cryosphere first. Most population corridors in Asia are settled snugly around what the first settlers assumed would be constant outflow from Himalayan glaciers—but now are poised to lose their fresh water supply.
Others on the coast are already being flooded by melting and calving ice in the form of sea level rise. Some 250 million people live on land less than three feet above the current sea level. And 2.5 billion live within sixty miles of a coastline. “Asia has all the megacities, and they are all at sea level,” Dr. Steffen said. “The area behind them is already heavily populated. These people cannot just move back…One meter of sea level rise globally means — locally, with high tide and on‑slope winds, maybe two to two and a half meters. It will close the cities, including New York. So where are the people going to go?”
In a macabre example of the symbiotic relationship between human life and the health of the cryosphere, Dr. Steffen himself fell into a new crevasse at Swiss Camp and died just a few months after we spoke.
The end of my journey coincided with the dawn of the COVID-19 pandemic, and I marveled at the same repudiation of science that I had seen from climate deniers for years—championed by many of the same characters. Things have not gone well for nonbelievers in the pandemic. The same will be true of climate change, except that the nonbelievers will not suffer alone. Every person on the planet will feel earth’s wrath if we continue to burn fossil fuel.
I caught the last plane out of Greenland as COVID-19 shut the world down. Listening to ambulances race down our street in Brooklyn days later, I thought about something a scientist in Juneau named Brad Markle said about the uniquely stable climate humans have enjoyed. “Ten thousand years ago, it gets warmer, the ice melts, flows into farmland, and [we] develop agriculture, civilization, all the history we have ever heard of, all the people and wars, love stories, everything,” he said. “All of our crops were developed in that very narrow temperature range. And the only thing that changed was the climate. The difference was like four or five degrees. I find that sobering: the history of human civilization entirely depends on climate.”
It would do us well to recognize how unique our current climate is, compared to the violent history of earth’s temperature swings. And to understand how the cool, reflective crust of ice and snow now draped around the poles is the final buffer between us and radical climate change. There is a metaphor here somewhere about how all things on earth are interconnected, but perhaps a simpler explanation is more appropriate at this late date: lose the cryosphere and we lose the world we know. It is no longer theory. It is happening outside your window right now.