05/08/2017

Are We Doomed? Let’s Have a Conversation.

Post Carbon Institute - Richard Heinberg

My most recent essay, in which I discussed a highly publicized controversy over the efficacy of plans for a comprehensive transition to an all-renewable energy future, garnered some strong responses.
“If you are right,” one Facebook commenter opined, “we are doomed. Fortunately you are not right.” (The commenter didn’t explain why.)
What had I said to provoke an expectation of cataclysmic oblivion? Simply that there is probably no technically and financially feasible energy pathway to enable those of us in highly industrialized countries to maintain current levels of energy usage very far into the future.
My piece happened to be published right around the same time New York Magazine released a controversial article titled “The Uninhabitable Earth,” in which author David Wallace Wells portrayed a dire future if the most pessimistic climate change models turn to reality. “It is, I promise, worse than you think,” wrote Wells. “If your anxiety about global warming is dominated by fears of sea-level rise, you are barely scratching the surface of what terrors are possible, even within the lifetime of a teenager today.”
Wells’s article drew rebukes from—of all people—climate scientists, who pointed out a few factual errors, but also insisted that scaring the public just doesn’t help. “Importantly, fear does not motivate,” responded Michael Mann with Susan Joy Hassol and Tom Toles, “and appealing to it is often counter-productive as it tends to distance people from the problem, leading them to disengage, doubt and even dismiss it.”
It’s true: apocalyptic warnings don’t move most people. Or, rather, they move most people away from the source of discomfort, so they simply tune out. But it’s also true that people feel a sense of deep, unacknowledged unease when they are fed “solutions” that they instinctively know are false or insufficient.
Others came to Wells’s defense. Margaret Klein Salamon, a clinical psychologist and founder of the climate action group The Climate Mobilization, which advocates for starting a “World War II-scale” emergency mobilization to convert from fossil fuels, writes, “it is OK, indeed imperative, to tell the whole, frightening story. . . . [I]t’s the job of those of us trying to protect humanity and restore a safe climate to tell the truth about the climate crisis and help people process and channel their own feelings—not to preemptively try to manage and constrain those feelings.”
So: Are we doomed if we can’t maintain current and growing energy levels? And are we doomed anyway due to now-inevitable impacts of climate change?
First, the good news. With regard to energy, we should keep in mind the fact that today’s Americans use roughly twice as much per capita as their great-grandparents did in 1925. While people in that era enjoyed less mobility and fewer options for entertainment and communication than we do today, they nevertheless managed to survive and even thrive. And we now have the ability to provide many services (such as lighting) far more efficiently, so it should be possible to reduce per-capita energy usage dramatically while still maintaining a lifestyle that would be considered more than satisfactory by members of previous generations and by people in many parts of the world today. And reducing energy usage would make a whole raft of problems—climate change, resource depletion, the challenge of transitioning to renewable energy sources—much easier to solve.
The main good news with regard to climate change that I can point to (as I did in an essay posted in June) is that economically recoverable fossil fuel reserves are consistent only with lower-emissions climate change scenarios. As BP and other credible sources for coal, oil, and natural gas reserves figures show, and as more and more researchers are pointing out, the worst-case climate scenarios associated with “business as usual” levels of carbon emissions are in fact unrealistic.
Now, the bad news. While we could live perfectly well with less energy, that’s not what the managers of our economy want. They want growth. Our entire economy is structured to require constant, compounded growth of GDP, and for all practical purposes raising the GDP means using more energy. While fringe economists and environmentalists have for years been proposing ways to back away from our growth addiction (for example, by using alternative economic indices such as Gross National Happiness), none of these proposals has been put into widespread effect. As things now stand, if growth falters the economy crashes.
There’s bad climate news as well: even with current levels of atmospheric greenhouse gases, we’re seeing unacceptable and worsening impacts—raging fires, soaring heat levels, and melting icecaps. And there are hints that self-reinforcing feedbacks maybe kicking in: an example is the release of large amounts of methane from thawing tundra and oceanic hydrates, which could lead to a short-term but steep spike in warming. Also, no one is sure if current metrics of climate sensitivity (used to estimate the response of the global climate system to a given level of forcing) are accurate, or whether the climate is actually more sensitive than we have assumed. There’s some worrisome evidence the latter is case.
But let’s step back a bit. If we’re interested in signs of impending global crisis, there’s no need to stop with just these two global challenges. The world is losing 25 billion tons of topsoil a year due to current industrial agricultural practices; if we don’t deal with that issue, civilization will still crash even if we do manage to ace our energy and climate test. Humanity is also over-using fresh water: ancient aquifers are depleting, while other water sources are being polluted. If we don’t deal with our water crisis, we still crash. Species are going extinct at a thousand times the pre-industrial rate; if we don’t deal with the biodiversity dilemma, we still crash. Then there are social and economic problems that could cause nations to crumble even if we manage to protect the environment; this threat category includes the menaces of over-reliance on debt and increasing economic inequality.
If we attack each of these problems piecemeal with technological fixes (for example, with desalination technology to solve the water crisis or geo-engineering to stabilize the climate) we may still crash because our techno-fixes are likely to have unintended consequences, as all technological interventions do. Anyway, the likelihood of successfully identifying and deploying all the needed fixes in time is vanishingly small.
Many problems are converging at once because society is a complex system, and the challenges we have been discussing are aspects of a systemic crisis. A useful way to frame an integrated understanding of the 21st century survival challenge is this: we humans have overshot Earth’s long-term carrying capacity for our species. We’ve been able to do this due to a temporary subsidy of cheap, bountiful energy from fossil fuels, which enabled us to stretch nature’s limits and to support a far larger overall population than would otherwise be possible. But now we are starting to see supply constraints for those fuels, just as the side effects of burning enormous amounts of coal, oil, and natural gas are also coming into view. Meanwhile, using cheap energy to expand resource-extractive and waste-generating economic processes is leading to biodiversity loss; the depletion of soil, water, and minerals; and environmental pollution of many kinds. Just decarbonizing energy, while necessary, doesn’t adequately deal with systemic overshoot. Only a reduction of population and overall resource consumption, along with a rapid reduction in our reliance on fossil fuels and a redesign of industrial systems, can do that.
Economic inequality is a systemic problem too. As we’ve grown our economy, those who were in position to invest in industrial expansion or to loan money to others have reaped the majority of the rewards, while those who got by through selling their time and labor (or whose common cultural heritage was simply appropriated by industrialists) have fallen behind. There’s no technological fix for inequality; dealing with it will require redesigning our economic system and redistributing wealth. Those in wealthy nations would, on average, have to adjust their living standards downward.
Now, can we do all of this without a crash? Probably not. Indeed, many economists would regard the medicine (population reduction, a decline in per-capita energy use, and economic redistribution) as worse than whatever aspects of the disease they are willing to acknowledge. Environmentalists and human rights advocates would disagree. Which is to say, there’s really no way out. Whether we stick with business as usual, or attempt a dramatic multi-pronged intervention, our current “normal” way of life is toast.
Accepting that a crash is more or less inevitable is a big step, psychologically speaking. I call this toxic knowledge: one cannot “un-know” that the current world system hangs by a thread, and this understanding can lead to depression. In some ways, the systemic crisis we face is analogous to the individual existential crisis of life and death, which we each have to confront eventually. Some willfully ignore their own mortality for as long as possible; others grasp at a belief in the afterlife. Still others seek to create meaning and purpose by making a positive difference in the lives of those around them with whatever time they have. Such efforts don’t alter the inevitability of death; however, contributing to one’s community appears to enhance well-being in many ways beyond that of merely prolonging life.
But is a crash the same as doom?
Not necessarily. Our best hope at this point would seem to be a controlled crash that enables partial recovery at a lower level of population and resource use, and that therefore doesn’t lead to complete and utter oblivion (human extinction or close to it). Among those who understand the systemic nature of our problems, the controlled crash option is the subject of what may be the most interesting and important conversation that’s taking place on the planet just now. But only informed people who have gotten over denial and self-delusion are part of it.
This discussion started in the 1970s, though I wasn’t part of it then; I joined a couple of decades later. There is no formal membership; the conversation takes place through and among a patchwork of small organizations and scattered individuals. They don’t all know each other and there is no secret handshake. Some have publicly adopted the stance that a global crash is inevitable; most soft-pedal that message on their organizational websites but are privately plenty worried. During the course of the conversation so far, two (not mutually exclusive) strategies have emerged.
The first strategy envisions convincing the managers and power holders of the world to invest in a no-regrets insurance plan. Some systems thinkers who understand our linked global crises are offering to come up with a back-pocket checklist for policy makers, for moments when financial or environmental crisis hits: how, under such circumstances, might the managerial elite be able to prevent, say, a stock market crash from triggering food, energy, and social crises as well? A set of back-up plans wouldn’t require detailed knowledge of when or how crisis will erupt. It wouldn’t even require much of a systemic understanding of global overshoot. It would simply require willingness on the part of societal power holders to agree that there are real or potential threats to global order, and to accept the offer of help. At the moment, those pursuing this strategy are working mostly covertly, for reasons that are not hard to discern.
The second strategy consists of working within communities to build more societal resilience from the ground up. It is easier to get traction with friends and neighbors than with global power holders, and it’s within communities that political decisions are made closest to where the impact is felt. My own organization, Post Carbon Institute, has chosen to pursue this strategy via a series of books, the Community Resilience Guides; the “Think Resilience” video series; and our forthcoming compendium, The Community Resilience Reader.  Rob Hopkins, who originated the Transition Towns movement, has been perhaps the most public, eloquent, and upbeat proponent of the local resilience strategy, but there are countless others scattered across the globe.
Somehow, the work of resilience building (whether top-down or bottom-up) must focus not just on maintaining supplies of food, water, energy, and other basic necessities, but also on sustaining social cohesion—a culture of understanding, tolerance, and inquiry—during times of great stress. While it’s true that people tend to pull together in remarkable ways during wars and natural disasters, sustained hard times can lead to scapegoating and worse.
Most people are not party to the conversation, not aware that it is happening, and unaware even that such a conversation is warranted. Among those who are worried about the state of the world, most are content to pursue or support efforts to keep crises from occurring by working via political parties, religious organizations, or non-profit advocacy orgs on issues such as climate change, food security, and economic inequality. There is also a small but rapidly growing segment of society that feels disempowered as the era of economic growth wanes, and that views society’s power holders as evil and corrupt. These dispossessed—whether followers of ISIS or Infowars—would prefer to “shake things up,” even to the point of bringing society to destruction, rather than suffer the continuation of the status quo. Unfortunately, this last group may have the easiest path of all.
By comparison, the number of those involved in the conversation is exceedingly small, countable probably in the hundreds of thousands, certainly not millions. Can we succeed? It depends on how one defines “success”—as the ability to maintain, for a little longer, an inherently unsustainable global industrial system? Or as the practical reduction in likely suffering on the part of the survivors of the eventual crash? A related query one often hears after environmental lectures is, Are we doing enough? If “Enough” means “enough to avert a system crash,” then the answer is no: it’s unlikely that anyone can deliver that outcome now. The question should be, What can we do—not to save a way of life that is unsalvageable, but to make a difference to the people and other species in harm’s way?
This is not a conversation about the long-term trajectory of human cultural evolution, though that’s an interesting subject for speculation. Assuming there are survivors, what will human society look like following the crises ensuing from climate change and the end of fossil fuels and capitalism? David Fleming’s Surviving the Future and John Michael Greer’s The Ecotechnic Future offer useful thoughts in this regard. My own view is that it’s hard for us to envision what comes next because our imaginations are bounded by the reality we have known. What awaits will likely be as far removed from from modern industrial urban life as Iron-Age agrarian empires were from hunting-and-gathering bands. We are approaching one of history’s great discontinuities. The best we can do under the circumstances is to get our priorities and values straight (protect the vulnerable, preserve the best of what we have collectively achieved, and live a life that’s worthy) and put one foot in front of the other.
The conversation I’m pointing to here is about fairly short-term actions. And it doesn’t lend itself to building a big movement. For that, you need villains to blame and promises of revived national or tribal glory. For those engaged in the conversation, there’s only hard work and the satisfaction of honestly facing our predicament with an attitude of curiosity, engagement, and compassion. For us, threats of doom or promises of utopia are distractions or cop-outs.
Only those drawn to the conversation by temperament and education are likely to take it up. Advertising may not work. But having a few more hands on deck, and a few more resources to work with, can only help.

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Superannuation Trustee Duties And Climate Risk

Environmental Justice Australia - David Barnden


A new legal opinion on climate change and trustee directors’ duties has wide-reaching ramifications for Australia’s $2.3 trillion superannuation industry, Environmental Justice Australia said today.
The opinion by Noel Hutley SC and James Mack, released today by EJA and Market Forces, states: “climate change risks can and should be considered by trustee directors to the extent that those risks intersect with the financial interests of a beneficiary of a registrable superannuation entity”.
In the barristers’ opinion, a prudent superannuation fund trustee should:
  • seek out information and obtain advice on a significant investment decision that involves a substantial exposure to climate change risks;
  • record why they were satisfied any investment was in the best interests of beneficiaries, notwithstanding the risks.
The legal framework for superannuation fund trustees imposes a higher standard than what is expected of company directors, due to the absence of the business judgment rule.
The opinion notes that the Australian Prudential Regulatory Authority, APRA, is likely to administer its regulatory functions on the understanding that climate change presents a financial risk, as distinct from an environmental, social or governance risk.
“The trustees of Australia’s $2.3 trillion superannuation industry must take climate change seriously,” said EJA lawyer David Barnden.
“Barristers Hutley SC and Mack have set out the law in this new opinion.
“We expect to see the industry act to adequately take into account climate change risks when investing the money of working Australians.
“Superannuation trustees that do not adequately take account of climate risks will leave themselves open to legal action.”
The opinion extends a October 2016 opinion on Climate Change and Directors’ Duties by Noel Hutley SC and Sebastian Hartford Davis, commissioned by the Centre for Policy Development and the Future Business Council with the assistance of Sarah Barker and Maged Girgis at Minter Ellison.

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The Larsen C Ice Shelf Collapse Is Just the Beginning—Antarctica Is Melting

National GeographicDouglas Fox*

The massive iceberg that broke off the Larsen C Ice Shelf may be a harbinger of a continent-wide collapse that would swamp coastal cities around the world.
A startling sunset reddens the Lemaire Channel, off the west coast of the Antarctic Peninsula. The continent's coastal ice is crumbling as the sea and air around it warm. Photograph Camille Seaman
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Seen from above, the Pine Island Ice Shelf is a slow-motion train wreck. Its buckled surface is scarred by thousands of large crevasses. Its edges are shredded by rifts a quarter mile across. In 2015 and 2016 a 225-square-mile chunk of it broke off the end and drifted away on the Amundsen Sea. The water there has warmed by more than a degree Fahrenheit over the past few decades, and the rate at which ice is melting and calving has quadrupled.
On the Antarctic Peninsula, the warming has been far greater—nearly five degrees on average. That's why a Delaware-size iceberg just broke off the Larsen C Ice Shelf and why smaller ice shelves on the peninsula have long since disintegrated entirely into the waters of the Weddell Sea. But around the Amundsen Sea, a thousand miles to the southwest on the Pacific coast of Antarctica, the glaciers are far larger and the stakes far higher. They affect the entire planet.

See the Giant Crack in Larsen C Ice Shelf That Yielded Antarctica Iceberg

The Pine Island Ice Shelf is the floating terminus of the Pine Island Glacier, one of several large glaciers that empty into the Amundsen Sea. Together they drain a much larger dome of ice called the West Antarctic Ice Sheet, which is up to two and a half miles thick and covers an area twice the size of Texas. The ice sheet is draped over a series of islands, but most of it rests on the floor of a basin that dips more than 5,000 feet below sea level. That makes it especially vulnerable to the warming ocean. If all that vulnerable ice were to become unmoored, break into pieces, and float away, as researchers increasingly believe it might, it would raise sea level by roughly 10 feet, drowning coasts around the world.
The ice sheet is held back only by its fringing ice shelves—and those floating dams, braced against isolated mountains and ridges of rock around the edges of the basin, are starting to fail. They themselves don't add much to sea level, because they're already floating in the water. But as they weaken, the glaciers behind them flow faster to the sea, and their edges retreat. That's happening now all around the Amundsen Sea. The Pine Island Ice Shelf, about 1,300 feet thick over most of its area, is a dramatic case: It thinned by an average of 150 feet from 1994 to 2012. But even more worrisome is the neighboring Thwaites Glacier, which could destabilize most of the West Antarctic Ice Sheet if it collapsed.
"These are the fastest retreating glaciers on the face of the Earth," says Eric Rignot, a glaciologist at the NASA Jet Propulsion Laboratory in Pasadena, California. Rignot has studied the region for more than two decades, using radar from aircraft and satellites, and he believes the collapse of the West Antarctic Ice Sheet is only a matter of time. The question is whether it will take 500 years or fewer than a hundred—and whether humanity will have time to prepare.
"We have to get these numbers right," Rignot says. "But we have to be careful not to waste too much time doing that."
Getting the predictions right requires measurements that can be made only by going to the ice. In December 2012 a red-and-white Twin Otter plane skimmed low over the Pine Island Ice Shelf. The pilot dragged the plane's skis through the snow, then lifted off and circled back to make sure he hadn't uncovered any crevasses. After the plane landed, a single person disembarked. Tethered to the plane by a rope and harness, he probed the snow with an eight-foot rod.
A diver watches an emperor penguin as it swims nearby. The brown patches above are microalgae, which cling to sea ice and photosynthesize in the spring. Photograph Laurent Ballesta
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Finally the scout was satisfied: There were no buried crevasses that might swallow a landing party. More scientists got out of the plane. The team, led by glaciologist Martin Truffer of the University of Alaska, proceeded to set up camp. Their plan was to spend two months on the ice shelf; they would be the first humans to spend even a single night. The ice had long been considered too dangerous to visit. But Truffer's team wanted to bore holes all the way through the ice shelf, so they could measure the heat eating at it from the seawater below.
As the researchers lay in their tents at night, in the middle of a 4,000-mile arc of coastline that lacked a single permanent outpost, they heard loud pops and bangs coming from the ice. Each morning they saw new cracks, an inch wide and seemingly bottomless, cutting across its surface. During their five weeks of studying it, the ice under their boots thinned by another seven feet.
It took scientists a long time to realize just how quickly West Antarctica's ice could melt. In part that's because the most vulnerable glaciers are so well guarded. In front of the Pine Island Ice Shelf—the floating end of the glacier—the sea surface itself freezes each winter. In summer this fractured sea ice joins icebergs calved from the ice shelves to form a shifting palisade that historically kept ships at least a hundred miles from the ice shelf.
In March 1994 the U.S. icebreaker Nathaniel B. Palmer became perhaps only the second vessel ever to reach it. For a few days powerful winds parted the ice floes, creating a narrow, ephemeral passage for the Palmer to thread. With no accurate maps to guide them, the crew on the ship's bridge eyed the sonar monitor nervously. It showed a chaotic seafloor of canyons and sharp ridges, including one that rose within 20 feet of the ship's keel.
The west side of the Antarctic Peninsula is warming several times faster than the rest of the planet. Ninety percent of its 674 glaciers are now in retreat and are calving more icebergs into the sea, like this one in Andvord Bay.
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The Palmer would spend just 12 hours at the front of the ice shelf before encroaching sea ice forced it to retreat north. But that gave the crew enough time to lower scientific instruments through the water column. They made a disturbing discovery. Near the surface, a current was streaming out from under the ice shelf that was slightly less salty than the sea around it, because it was freshened by melted ice. (The ice is fresh because it originated as snow falling on West Antarctica.) And at depths of 2,000 to 3,000 feet, along a seafloor canyon that ran straight under the ice, warmer seawater was streaming in.
Stan Jacobs, an oceanographer from the Lamont-Doherty Earth Observatory in New York, quickly understood what was going on. The warm water was coming from the South Pacific, more than 200 miles north. It was so heavy with salt that it was following the floor of a submarine canyon, which sloped down toward the glacier. The glacier itself had carved that canyon, thousands of years ago during the Ice Age, when it and the other glaciers in West Antarctica advanced hundreds of miles out from their present-day positions.
Now that same canyon was channeling warm ocean water under the Pine Island Ice Shelf. Somewhere tens of miles inland, the warm water was finding the "grounding line": the place where the glacier lifts off the seafloor and becomes a floating ice shelf. Hitting that wall of ice, the warm water was eroding it, producing a steady stream of melt-laden seawater. Because it was cooler and fresher, it was less dense, and so it was rising above the warmer, incoming water and flowing back out to sea just under the shelf.
By measuring the amount of this freshwater, the researchers could estimate how much ice was being lost. The melt rates "were just crazy," says Adrian Jenkins, a glaciologist from the British Antarctic Survey in Cambridge. According to his calculations, the ice shelf was losing 13 cubic miles of ice per year from its underside; back near the grounding line, the ice was probably thinning up to 300 feet per year.
"It was just beyond our concept that a glacier would melt that fast," Jenkins says.
In East Antarctica, Australian researchers probe for crevasses on Totten Glacier—another one that has begun to look vulnerable—before deploying instruments to measure how fast it's moving and thinning. Photograph by Camille Seaman
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Over the next 13 years he and Jacobs tried three times to return to Pine Island. Sea ice blocked them each time. When they finally got back there on the Palmer in January 2009, they found that the melt rate had increased by about 50 percent. This time they came equipped with a new tool: a yellow robotic submarine called Autosub3. Shaped like a torpedo and as long as a delivery truck, it could navigate autonomously under the ice shelf, out of contact with the ship, for up to 30 hours at a time.
On its first three dives, Autosub3 discovered that the ice shelf had thinned enough to lift off a submarine ridge that, running across its width, had once supported and stabilized the ice shelf. That had opened a gap that was allowing warm water to flow in and melt the underside of the ice even faster. On its fourth dive the yellow robot nearly died. When the crew winched it out of the water, they found its nose cone smashed and some of its delicate internal equipment damaged.
Technicians reconstructed what had happened from the sub's navigation data. Thirty miles back, under the ice shelf, Autosub3 had strayed into a chasm on the underside of the ice. Searching for a way forward, it had smashed and scraped against the walls of the chasm—ultimately rising 500 feet up into the labyrinthine bowels of the ice shelf. Finally it had dropped back out and escaped into open water.
The ice shelves, Fricker says, 'are the canary in the coal mine.'
The sub's sonar data, meanwhile, revealed the breathtaking landscape it had navigated. The bottom of the ice shelf was corrugated with not just one but many channels, which cut as far as 600 feet up into it. The walls of these inverted ice canyons were sculpted into terraces, ledges, and sharp corners, and along the ceiling of each ran a gaping crack that penetrated even farther into the ice.
"What the hell is going on?" Jenkins recalls thinking when he first saw the sonar maps.
What he and Jacobs came to realize was that the upside-down canyons had been carved, like rock canyons on land, by flowing water. Apparently the meltwater rising off the grounding line was still warm enough to melt more ice. And as it flowed for tens of miles along the underside of the ice shelf, back out to the open sea, it was melting a lot of it.


Antarctica is melting at a dangerous pace — here's why

Large swaths of West Antarctica are hemorrhaging ice these days. The warming has been the most dramatic on the Antarctic Peninsula, a spine of ice-cloaked mountains that reaches 700 miles up toward the tip of South America. Catching the powerful winds and ocean currents that swirl endlessly around Antarctica, the peninsula gets slammed with warm air and water from farther north. Average annual temperatures on its west side have risen nearly 5 degrees Fahrenheit since 1950—several times faster than the rest of the planet—and the winters have warmed an astonishing 9 degrees. Sea ice now forms only four months a year instead of seven.
Since 1988, four ice shelves on the east side of the peninsula have disintegrated into armadas of icebergs. (The Larsen C Ice Shelf may one day do the same, judging from that Delaware-size ice chunk that's about to break off it.) Warmer air helped trigger these collapses by forming meltwater ponds on the surface of ice shelves; the ponds drained into crevasses, wedging them deeper into the ice. As the shelves have vanished, the glaciers they once stabilized have stampeded into the ocean, accelerating to two, five, even nine times their original speed. They're relatively small glaciers and won't raise sea level much—but their acceleration has reinforced concerns that the same thing might happen to the much larger glaciers along the Amundsen Sea.
The Amundsen Sea is farther south than the peninsula, and the air there is not as warm. The biggest threat to its glaciers is the mechanism Jacobs and Jenkins helped uncover: deep submarine canyons that channel warm water from the north under the ice shelves, and deep inverted canyons that focus the warmth on the underside of the ice.
A satellite survey last year of many Antarctic ice shelves—led by glaciologists Ted Scambos of the National Snow and Ice Data Center in Boulder, Colorado, and Helen Fricker of the Scripps Institution of Oceanography in San Diego—revealed that such melt canyons are common. They tend to fan out and steer warm water toward the edges of the shelves. The ice there is crucial: It rubs against the stationary banks and slows the flow of the shelf and the glacier behind it. But that edge ice is also thinner than the rest. This "is something that bears watching," Scambos said in early 2016.
Ian Howat, of the Byrd Polar and Climate Research Center in Columbus, Ohio, is another glaciologist who's watching Pine Island closely. Last November he reported two ominous new rifts spreading across the ice shelf that threaten to prune it to its shortest length in recorded history. As Howat looked back through monthly satellite photos, he realized that the rifts had been triggered by a singular event that had happened, unnoticed, three years before. The strip of torn-up ice anchoring the ice shelf to its northern bank had suddenly fallen apart, suggesting it had been undermined by melting from below. It blew out "just in a matter of days," Howat says, "like a zipper, unzipping the side of the glacier."
It's unclear when the entire ice shelf might disintegrate. The "warm" water flowing underneath it from offshore is only 4 to 6 degrees Fahrenheit above freezing. But roughly 3,000 cubic miles of it arrives every year, which means the ice shelf is receiving an amount of heat that exceeds the output of a hundred nuclear power plants, operating 24/7.
An iceberg's graceful curves bear witness to the rapid melt it has experienced since being dumped by a glacier into the Lemaire Channel. Winters on the west side of the Antarctic Peninsula have warmed by 9 degrees Fahrenheit since 1950.
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When Truffer and his team camped on the shelf in December 2012, they could sense how it had already weakened. As the meltwater cuts deep into the ice from below, the unsupported ice sags, causing the entire shelf to bend and warp. Crevasses erupt along the lines of stress, on both the top and the bottom of the ice. The pops and bangs the researchers heard and the daily opening of new cracks bore witness to the ice's gradual failure as it thinned and broke down beneath them.
As the Pine Island Ice Shelf has weakened and the glacier behind it has accelerated, the ice has stretched and thinned for 150 miles inland from the coast. The destabilizing effects spread farther into West Antarctica every year. "A little nudge can get you to several decades of retreating behavior that's hard to reverse," Truffer says.
In fact, research by Rignot and others over the past few years indicates that the collapse of several major glaciers flowing into the Amundsen Sea is now unstoppable. Between 2002 and 2009 alone, the ice shelf in front of the Smith Glacier thinned by 1,500 feet in some places, the one in front of the Pope Glacier by up to 800 feet. The grounding lines of the Amundsen glaciers have retreated so far—tens of miles in some cases—that they now rest on seafloor that slopes down toward the center of the ice sheet. Each increment of retreat exposes a greater ice surface to warm ocean water. It's a runaway process—and scientists are urgently trying to figure out how fast it will run.
The ice shelves, Fricker says, "are the canary in the coal mine." Because they're already floating, they don't raise sea level themselves when they melt—but they signal that a rise is imminent, as the glaciers behind them accelerate. Fricker and her team have found that from 1994 to 2012, the amount of ice disappearing from all Antarctic ice shelves, not just the ones in the Amundsen Sea, increased 12-fold, from six cubic miles to 74 cubic miles per year. "I think it's time for us scientists to stop being so cautious" about communicating the risks, she says.
The retreat and hemorrhage of these glaciers "will accelerate over time," agrees Rignot. "Maybe you don't care much about that for the next 30 to 40 years, but from 2050 to 2100 things could get really bad, and at that point listening to scientists is irrelevant." Yet after things get really bad, they could still get worse.
Iceberg A56, photographed through clouds from the International Space Station, is several times the size of Manhattan. It has drifted over 1,000 miles since breaking off the Filchner-Ronne Ice Shelf around 2000.
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Most of the heat trapped by our fossil fuel emissions since the industrial revolution began in the 19th century has gone into the ocean. Most of the heat now hitting the Antarctic ice shelves, however, comes from another effect of climate change: Intensified circumpolar winds and currents have driven warmer water from offshore onto the continental shelf and under the floating ice. Much more ocean warming is yet to come, even if we begin to cut emissions. A lot more heat is on the way to Antarctica.
Scientists are especially concerned about the Thwaites Glacier, which by itself could raise global sea level four feet; last fall the British and American science foundations announced a coordinated $20 million to $25 million field campaign that will deploy ships, planes, satellites, and underwater robots to assess the glacier's status starting in 2018. For now, the best estimates suggest that Antarctica will sweat off enough ice to raise global sea levels by 1.5 to 3.5 feet by 2100, depending on how quickly humans continue to pump out greenhouse gases. Throw in Greenland and other rapidly melting glaciers around the world, and sea level could plausibly rise three to seven feet by 2100.
But that's not the worst case: Sea level won't stop rising in 2100. Earth's past offers worrisome clues to what the more distant future might bring. Geologists studying ancient shorelines have concluded that 125,000 years ago, when the Earth was only slightly warmer than today, sea levels were 20 to 30 feet higher. Some three million years ago, the last time atmospheric carbon dioxide was as high as it is today, and the temperature was about what it's expected to be in 2050, sea levels were up to 70 feet higher than today. Yet a collapse of the Greenland and West Antarctic Ice Sheets would raise sea level only about 35 feet.
To consider the worst case, then, scientists must turn their eyes toward East Antarctica, home to more than three-fourths of all the ice on Earth.
This past January a twin-propeller DC-3 made a series of flights from Australia's Casey Station along the East Antarctic coast. Built in 1944, the plane was packed with modern scientific equipment. As it flew over the Totten Glacier, a radar recorded the thickness of the ice. Another instrument recorded tiny changes in Earth's gravitational field—clues to the topography of the seafloor under the glacier's floating ice shelf. Now and then a crew member opened the plane's rear door, knelt in the windy opening, and tossed out a torpedo-shaped object. As the device splashed into the water, it split in two: One part floated, sending radio signals back to the plane, while the other part reeled down 2,600 feet of wire, measuring the water temperature all the way down.
Until recently the East Antarctic Ice Sheet was considered secure; unlike West Antarctica, it sits on high ground. But mapping with ice-penetrating radar has revealed a low-lying region cut by glacially carved channels that drop as far as 8,500 feet below sea level—perfect for guiding warm ocean water deep into the heart of the ice sheet. The Totten Glacier is the largest coastal outlet in this region. If it collapsed, global sea level could rise 13 feet—"roughly as much as all of West Antarctica," Rignot points out. "One glacier alone."
In January 2015, the Australian icebreaker Aurora Australis became the first ship to reach the front of Totten. Like the Palmer at Pine Island in 1994, it found deep, warm water flowing under the ice shelf, at a rate of 4.5 cubic miles a day. The glacier is already losing a couple of cubic miles of ice per year—small potatoes, in Antarctic terms. But Donald Blankenship, a University of Texas glaciologist who oversees the aerial survey, fears it could blow up.
In 2016 his team reported evidence from the bedrock that Totten repeatedly has retreated 100 to 200 miles inland from its current position—meaning it might help explain why sea level was so much higher three million years ago. Blankenship's surveys have also identified two seafloor grooves deep enough to let warm water under Totten's ice shelf. Last January the team was refining those seafloor maps.
Totten will lose its ice more slowly than West Antarctica. The worst case coming out of Antarctica still seems to be centuries away. But it would mean abandoning many of the world's largest cities, including New York, Los Angeles, Copenhagen, Shanghai, and dozens of others—and it's looking less crazy all the time. "The fuse is lit," says Blankenship. "We're just running around mapping where all the bombs are."

Writer Douglas Fox has traveled to Antarctica five times and has spent months on the ice there. This is his first feature for National Geographic magazine.

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