Runaway Planet:
How Global Warming is Already Changing the Earth

The Washington Post

Copyright

Diversion Books
A Division of Diversion Publishing Corp.
443 Park Avenue South, Suite 1008
New York, NY 10016
www.DiversionBooks.com

Copyright © 2015 by The Washington Post
All rights reserved, including the right to reproduce this book or portions thereof in any form whatsoever.

For more information, email info@diversionbooks.com

First Diversion Books edition December 2015
ISBN: 978-1-68230-279-8

Table of Contents

Introduction

The great thaw: As temperatures rise, many American glaciers could vanish in a few decades

‘It’s functionally gone’

‘Water is the lifeblood’

The invisible threat: Rising temperatures mean insects can carry viruses such as West Nile to wider areas

Bug collecting

Ticks and the ‘kissing bug’

That’s heavy: Climate-change warnings include rising seas and wild weather shifts. But giant flying boulders?

Eleuthera in the Eemian

The ‘rages’

The magic number: Holding warming under two degrees Celsius is the goal. But is it still attainable?

The ‘carbon budget’

The permafrost problem

Tech assumptions

More from The Washington Post…

Connect with Diversion Books

Introduction

2015 is sure to be remembered as a historic year – and, likely, a turning point – in the climate change debate.

A dramatic El Nino event means 2015 is virtually assured to be the hottest year on record. It's also the year that Pope Francis reframed the narrative and made the climate issue about protecting the poor and vulnerable. And the U.S. finally launched a policy to curb greenhouse gas emissions from the power sector, in the form of the Clean Power Plan.

Most of all, though, it's the year when the world at last mobilized to take action on climate change at a historic United Nations meeting in Paris, France. With well over 100 pledges by individual countries to cut their emissions, the eventalready has consolidated more climate action than occurred at the ill-starred 2009 Copenhagen climate conference.

So many signs of action, and so many reasons for it – but as this book shows, the problem is far from fixed, and major changes are already upon us. Countries are now racing against time and very simple physics, and, at least on a few fronts, it's a race they’re losing.

Glaciers around the world are in rapid retreat – both smaller, mountain glaciers based on land and much larger glaciers, sometimes rooted deep below sea level, in key parts of Greenland and Antarctica. This represents nothing less than the early stages of what scientists might call a deglaciation – a planetary shift into a world featuring less ice on land or above sea level, which means much more water in the oceans and, thus, higher seas.

Meanwhile, as temperatures creep upward, major changes to biological systems are also underway. After all, temperatures are a crucial influence on the underlying chemistry of life itself.

Not every change is immediate and dramatic. Some are subtle or even nearly invisible – such as the spread of insects that carry tropical diseases into more northern latitudes. But that, too, is already happening.

So where does it end? The world's negotiators are now trying to land the plane and hoping there is still some runway left. But it doesn't help that this is our first flight.

The widely cited temperature target of holding warming to 2 degrees Celsius above pre-industrial levels – previously considered to be a "safe" threshold for climate change, though recently many doubts have been raised about this – is not yet within reach. Currently pledged emissions cuts are insufficient to get there. And as these pages show, even with about 1 degree Celsius of temperature rise so far above the temperatures that existed prior to the modern industrial age, major changes are happening, especially to the planet's ice.

The single biggest climate change development of the past two years is surely the discovery that even with this seemingly modest amount of warming, the great ice sheet of West Antarctica may already have been destabilized. Some scientists suggest it could be only a matter of time (granted, "time" here could mean hundreds or thousands of years) until the ice sheet contributes more than 3 meters, or more than 10 feet, of sea level rise.

So current – not future – changes are already real and, in some cases, profound. The key question becomes how much warming we'll actually see before temperatures peak, and how much change that will induce.

We simply don't know – but recently, James Hansen, the now-retired NASA researcher who put the climate issue on the political map in 1988, alarmed not only the public but many fellow climate scientists by outlining a new, dramatic scenario of potential change.

This idea is controversial. Parts of it have not yet passed peer review (as of this writing). But the claim is that in a past climate period not all that much warmer than our own – the Eemian interglacial, which appears to have ended tumultuously around 118,000 years ago – the planet saw not only major ice loss and sea level rise, but also sharp ocean circulation changes and a regime of megastorms.

Hansen and geologist Paul Hearty argue that all of this left its mark in the very rock of the Bahamas, where large megaboulders sit silently atop a high cliff overlooking the Atlantic. Hearty and Hansen think superstorms – not tsunamis, the usual culprit in these sorts of situations – flung the rocks up there during the Eemian period.

This is a contentious idea, but it helps underscore that the climate system is far from fully understood. It is not unreasonable to expect surprises, feedbacks and abrupt changes as thresholds are crossed in the system.

Many of these changes appear to involve ice – thus, these pages highlight a still overlooked problem in the climate debate, and climate policy generally. And this is that permafrost, frozen northern soil, contains a vast amount of carbon stored in the form of deceased, but not yet decomposed, plant life successively buried over vast time periods.

Permafrost is now thawing, and as decomposition takes over and microorganisms get to work, it will become a new source of greenhouse gas emissions. How much depends upon how fast the planet warms, but already, this source could be a significant addition to the burden of carbon in the atmosphere.

Thus, we release this book at a delicate moment – one that deftly balances fear and hope. Fear because the changes that we already see are more momentous than envisioned even a decade ago. Hope, because the world has at last begun to act in a way that suggests it recognizes this and takes it seriously.

Chris Mooney
The Washington Post

The great thaw

As temperatures rise, many American glaciers could vanish in a few decades

By Joby Warrick

WEST GLACIER, Mont. — The river of ice that hugs Mount Grinnell’s high ridges is neither big nor particularly beautiful, but it may be the most accessible glacier in all of North America. In as little as three hours, an average hiker can traverse the mountain’s well-groomed trail to plant a foot on a frozen relic of the Little Ice Age.

But if you want to see it, you’d better hurry. Grinnell Glacier is disappearing — fast.

This crescent-shaped glacier in Montana’s northern Rockies had been contracting for decades because of warming temperatures. Lately it has been shrinking at a breathtaking clip, losing as much as a 10th of its mass in a single year. As early as 2030, scientists say, it may no longer exist.

The glacier’s steep decline mirrors that of hundreds of other U.S. glaciers, from California’s Sierra Nevada to the North Cascades to the Central Alaska Range. All are in retreat, yet nowhere are the effects so profoundly felt as here in Glacier National Park, which experts say could be glacier-free by mid-century.

“They’ll be gone in a few decades,” said Dan Fagre, a scientist with the U.S. Geological Survey who monitors the park’s 25 remaining glaciers and plots each year’s losses. “Every year exposes rock that hasn’t seen daylight in centuries.”

The decline of glaciers here and around the world is frequently cited by scientists as evidence of a climate undergoing rapid change. Scientific studies have confirmed that more than 90 percent of the world’s glaciers are retreating, and many of the smaller ones — like the alpine ice sheets of Glacier National Park — are rapidly disappearing.

The impacts extend well beyond the loss of majestic scenery. Thawing glaciers account for about 20 percent of the sea-level rise recorded in the past century, adding to the meltwater coming from polar ice caps and ice sheets. In the United States, the loss of mountain glaciers and snow cover is depriving Western states of a critical water source during the summer, when snowmelt feeds streams and rivers and helps farmers and wildlife survive the dry months.

The problems will almost certainly grow worse for decades, no matter what the world’s nations do to address climate change, scientists say. That’s because at high mountain altitudes where most glaciers are found, temperatures are rising faster than in the valleys below, with all signs pointing to still-higher increases in the decades ahead.

At the end of 2015, Diplomats from more than 190 countries gathered in Paris to forge an agreement with the ultimate goal of cutting carbon pollution so that temperatures climb no more than two degrees Celsius (3.6 Fahrenheit) over historical averages.

But at Glacier National Park, temperatures already have jumped by nearly two degrees Celsius since 1990. What happens to the glaciers in the coming years, climate scientists say, could offer a preview of the broader changes that lie ahead for a warming planet.

“At this trajectory, within a few centuries most glaciers are going to be toast,” said Jeremy Shakun, an assistant professor of earth and environmental sciences at Boston College. “We’re orchestrating something akin to the end of an ice age, but much faster.”

‘It’s functionally gone’

For nearly 25 years, Fagre has been keeping watch on Glacier National Park’s ice fields with the concern of a physician tending to a room full of very sick patients. He scales the mountains regularly to take photographs and measurements, recording a steady decline that is counted in tons and meters.

Already there have been losses. Boulder Glacier, once a large ice field above the park’s Boulder Pass, was the backdrop for many a tourist photo, including a famous 1910 portrait of cowboys silhouetted against an immense field of white. It was still impressive in 1992, when Fagre first hiked to the glacier to take measurements. Today, nothing remains but a few slushy leftovers.

“I’ve gone there regularly enough to see it go from an awesome thing to a tiny strip clinging to the shadows,” said Fagre, a research ecologist and the park’s resident climate-change expert. “It’s functionally gone. What’s left is remnant ice, not a glacier.”

Scores of the park’s glaciers have experienced the same fate. In the mid-19th century, 150 glaciers existed within the boundaries of what became Glacier National Park. Only 25 remain, and already park officials are preparing for a time when the park so famous for its glaciers will no longer have them.

The park’s scientists acknowledge that glaciers can wax and wane for reasons unrelated to man-made climate change. Montana’s small alpine glaciers are less than 7,000 years old—young, by geological standards — and they have been gradually declining for at least a century, long before humans began emitting huge volumes of carbon dioxide into the atmosphere. George Bird Grinnell, the naturalist who in 1885 discovered the glacier that now bears his name, observed 90 years go that it appeared to be losing mass.

But there are unmistakable signs that the warming and thawing have accelerated. A 2003 scientific paper co-authored by Fagre mapped out possible futures for the park’s glaciers, with predictions that varied depending on the level of carbon pollution in the atmosphere. The most dire scenario predicts that all glaciers in the park’s main Blackfoot-Jackson Glacier Basin could be gone by 2030. The forecast, which drew scoffs at the time, now appears to have been slightly optimistic.

“We keep going beyond what we predicted a few years ago,” Fagre said.

The Grinnell Glacier, in another corner of the park, appears to be riding a similar trajectory. The small glacier has been photographed by tens of thousands of visitors and was famously visited in 1997 by Vice President Al Gore, who stood on the ice to call attention to climate change. The glacier has shriveled dramatically since then, losing scores of meters in length and shedding much of the imposing bulk remembered by journalists who accompanied Gore on the trip.

“We used to have to climb 15 to 20 feet on the land side to get on top of the glacier, and we worried about ice falling down on our people,” Fagre recalled. “Now it’s not even up to your kneecap.”

‘Water is the lifeblood’

The loss of Grinnell and its neighbors will almost certainly mean fewer visitors to a park that annually draws 2 million tourists eager to gawk at a real glacier. But that’s perhaps the least of the challenges the park’s managers could soon face.

With the retreat of the ice, new threats emerge daily to an alpine ecosystem that has evolved along the edges of glaciers. The park is home to rare insects and plants that exist only in a small zone near the ice, where the glacier provides year-round air conditioning. These little-noticed creatures are the first rungs in a complex food web that includes wolverines, as well as endangered bull trout, that survive only in very cold, oxygen-rich streams.

The glaciers also act as nature’s free reservoir system, providing the meltwater that keeps streams flowing and irrigation pumps working when rainfall is rare. Already, some of the park’s perennial streams are drying up during the summer months, and declining soil moisture leaves the park’s forest more vulnerable to disease and forest fires. Members of the Blackfeet Nation, a tribe on the park’s eastern fringe, say traditional watering holes used for cattle and irrigation are drying up.

“Whether you look at it culturally or scientifically, water is the lifeblood of the universe,” said Joe McKay, a member of the Blackfeet tribe’s business council. “In our world, glaciers then are not just drying up or disappearing. Glaciers are dying.”

The park’s neighbors aren’t the only ones bracing for major change. Rapid melting is underway in all seven U.S. states that have significant glaciers. Like those in Montana, some are on a fast glide toward extinction.

Boulder Glacier in 1913 (left) and 2012 (right). (Images courtesy of Northern Rocky Mountain Science Center)

In Wyoming, the Cloud Peak Glacier, the only named glacier in the Bighorn Mountain Range, is forecast to disappear by 2034. In Washington state’s North Cascades, scientists documented record rates of melting in 2015 for all the region’s alpine glaciers, which collectively lost between 5 and 7 percent of their mass in a single year. In Alaska, the only Arctic state, glaciers shed 75 gigatons — or 75 billion metric tons — each year between 1994 and 2013, an amount equal to half the ice loss for all of Antarctica.

Similarly impressive losses have been reported in other parts of the world. Greenland’s massive Jakobshavn Glacier set a record in August when it lost nearly five square miles of ice to a massive iceberg in a single day. Historic rates of melting have been observed for glaciers in the Himalayas, the European Alps, eastern Africa, New Zealand’s Southern Alps and the Peruvian Andes. The handful of glaciers that are not losing significant mass — those in the Arctic, for example — appear to be the outliers, experts say.

The fact that so many glaciers are retreating in near lock step is powerful evidence not only for the existence of climate change but also for the underlying cause, said Boston College’s Shakun. The last time the planet experienced so much melting was at the end of the last Ice Age, about 12,000 years ago, when volcanoes and a changing ocean discharged huge quantities of carbon dioxide into the atmosphere. The difference today is that the CO2 comes not from volcanoes but from smokestacks and exhaust pipes — and there is vastly more of it, Shakun said.

“We’ve already raised CO2 by more than it increased at the end of the Ice Age,” he said. “And we’re on track to go up much higher.”

The invisible threat

Rising temperatures mean insects can carry viruses such as West Nile to wider areas

By Joby Warrick

Microbiologist Spencer Lockwood separates mosquitoes to be tested for West Nile virus in Dallas. (Photo by Jeremy Lock)

DALLAS — Winter was oddly mild in northern Texas in 2012, a year that saw few snowflakes and barely any ice. When the cold failed to show up, the spring mosquitoes arrived in droves, carrying disease.

The insects multiplied during an unusually muggy May, when temperatures hit the 90s and then stayed there. On June 20, Dallas recorded the season’s first case of West Nile virus. By late August, there were nearly 400.

Nineteen people would die in the greater Dallas area in the worst West Nile outbreak in U.S. history. The 2012 epidemic alarmed health officials and triggered multiple inquiries into the possible causes. One finding would ring ominously in a region grappling with the impacts of climate change: When it comes to insect-borne disease, warmer is worse.

“With warmer weather, mosquitoes fly more and bite more. And warmth amplifies the infectivity and replication of the virus,” said Robert Haley, director of epidemiology at the University of Texas Southwestern Medical Center and co-author of a major study on the 2012 outbreak. “If everything else stays the same, you could predict that a warmer climate makes things worse.”

The Dallas epidemic underscored long-held concerns about a facet of climate change that strikes closest to home for millions of people across the U.S. heartland. Many of the predicted consequences of global warming — such as rising sea levels and more powerful storms — can seem remote, separated by time and geography from the daily concerns of most Americans.

But scientists say even a relatively modest rise in temperatures can trigger substantial changes within the invisible ecosystems in which pathogens and hosts interact. The results can be extraordinarily difficult to predict, but a preponderance of evidence suggests that a warmer United States will see greater numbers of insect pests and new waves of insect-borne disease.

Warming temperatures already appear to be bringing new disease threats as pests and pathogens normally associated with the tropics march steadily northward. Some, like the mosquito-borne chikungunya virus and dengue fever, had rarely been seen on the U.S. mainland. Others, such as the now-endemic West Nile virus, are showing up earlier in the year and lingering longer as winters grow steadily milder.

Health departments throughout the United States are already preparing for the onslaught, stepping up monitoring of insect carriers, or vectors, for the presence of West Nile and other viruses. Major Southern cities such as Dallas have introduced community-wide pesticide spraying for the first time in nearly half a century.

U.S. officials and scientists say the United States is well equipped to respond to new disease outbreaks compared with other parts of the world. But many also acknowledge the possibility of surprises, even at relatively modest levels of warming.

“Biology is notoriously nonlinear and full of thresholds beyond which all hell breaks loose, at least for a while,” said Daniel R. Brooks, an evolutionary biologist and senior research fellow at the University of Nebraska’s Manter Laboratory of Parasitology. “Think of a heart attack as an analogy. You can feel pretty good right up the point that you die.”

Microbiologist Spencer Lockwood shakes out a trap full of anesthetized mosquitoes in Dallas. (Photo by Jeremy Lock)

Bug collecting

Each week, Dallas County health workers set out scores of small traps in neighborhoods across the city and its suburbs, looking for infected mosquitoes that could offer an early warning about a possible disease risk.

The small traps are baited with a homemade broth called “stinkwater” that replicates the odors of the fetid swamps preferred by females for laying eggs. A small fan sucks the insects into the trap’s mesh net, which in a week’s time will catch scores or even hundreds of live insects.

At the lab, the mosquitoes are killed and then segregated by species. Then vials of dead mosquitoes are ground up and tested genetically for traces of West Nile virus. If mosquitoes from any neighborhood test positive, county officials return in their white pickup trucks and unleash a fog of pesticides to kill any insects nearby.

The spray trucks were initially controversial; some Dallas residents feared the chemicals more than the disease. But after 19 people died of West Nile in a single season, county officials felt compelled to act. Budgets were adjusted to accommodate dramatically higher levels of insect monitoring, and spray trucks returned to county streets for the first time since the 1960s.

“There is no way you can predict it. You just have to respond to it,” said Zachary Thompson, the director of the Dallas County health department. “We’re in America, where most citizens don’t want to stay in the house on a nice day.”

Local officials believe they are better equipped to detect and prevent a potential outbreak than they were three years ago, but they also acknowledge that the battlefield is changing. Long-term climatic data shows that Dallas, like the rest of the country, is warming, with shorter and generally milder winters. Fewer hard freezes means virus-infected mosquitoes have a greater chance of surviving the winter. And West Nile itself, which passes from birds to mosquitoes and then to humans, can begin to replicate and spread early in the season.

Whether a major outbreak occurs depends on multiple factors beyond weather. But studies have shown that the 2012 epidemic was enhanced by a warm-weather pattern that was ideal for the spread of the virus.

“We had a very warm winter — the fewest freeze days — and a period of drought punctuated by major rainstorms that filled up the culverts,” said Haley, the UT-Southwestern epidemiologist whose 2013 study on the causes of the epidemic was published in the Journal of the American Medical Association. “So, droughts alternating with rain, forcing the mosquitoes and birds to congregate, then warm temperatures and a hot, early summer — those were perfect conditions.”

The county’s intense monitoring and spraying campaign — coupled with a pair of unusually harsh Dallas winters — has helped keep the disease in check since 2012. But as temperatures rise, heightened vigilance is the new normal for Texas cities, Haley said.

“Climate change is broadening the tropical latitudes, and Texas is going to be tropical eventually,” Haley said. While the widespread return of major killers such as malaria are unlikely in an advanced Western country, he said, “you can roughly predict that tropical diseases will be part of our future.”

The small traps are baited with a homemade broth called “stinkwater” that replicates the odors of the fetid swamps. (Photo by Jeremy Lock)

Ticks and the ‘kissing bug’

But mosquitoes are not the only pests that thrive in warmer climates. Numerous recent studies have documented shifts in the habitats of other disease carriers.

Ticks, notorious for spreading Lyme disease as well as Rocky Mountain spotted fever, are expanding their range into parts of Canada. In the United States, milder winters mean shorter hibernations and booming tick populations in the spring and summer.

Southern states are seeing a resurgence of Chagas disease, a sometimes fatal parasitic infection spread by the beetlelike Rhodnius prolixus, or “kissing bug.” Regarded as a tropical disease, Chagas is moving farther north, with a spike in recent cases in Texas and new sightings of the insect carrier as far north as Indiana and Ohio, the Centers for Disease Control and Prevention reported this past week.

Behind each new disease occurrence is a multitude of contributing factors. Disease-carrying pests also can be spread through international travel and immigration. And climate change can sometimes limit, rather than expand, the ranges and life spans of certain insects and the microbes they carry, epidemiologists say.

But there is little doubt that a warmer climate will introduce new disease threats, said the University of Nebraska’s Brooks, and even a wealthy country with a sophisticated health-care system cannot expect to be entirely immune.

“The warmer the planet gets, the more pathogens and vectors from the tropics and sub-tropics are going to move into the temperate zones,” Brooks said. “Countries such as the United States tend to have a false sense of security, but vectors and pathogens don’t understand international boundaries. You can’t just put a fence to keep them out.”

That’s heavy

Climate-change warnings include rising seas and wild weather shifts. But giant flying boulders?

By Chris Mooney

One of the mysterious boulders on the island of Eleuthera in the Bahamas. Scientists have long debated how it got there. (Photo by Charles Ommanney)

ELEUTHERA, Bahamas — Standing atop a 60-foot cliff overlooking the Atlantic, James Hansen — the retired NASA scientist sometimes dubbed the “father of global warming” — examines two small rocks through a magnifying glass. Towering above him is the source of one of the shards: a huge boulder from a pair locals call “the Cow and the Bull,” the largest of which is estimated to weigh more than 1,000 tons.

The two giants have long been tourist attractions along this rocky coast. Perched not far from the edge of a steep cliff that plunges down into blue water, they raise an obvious question: How did they get up here?

Compounding the mystery, these two are among a series of giant boulders arranged in an almost perfect line across a narrow part of this 110-mile-long, wishbone-shaped island.

Hansen and Paul Hearty — a wiry, hammer-slinging geologist from the University of North Carolina at Wilmington who has joined him here as a guide — have a theory about these rocks. It’s so provocative — and, frankly, terrifying — that some critics wonder whether the man who helped spawn the whole debate about the dangers of climate change has finally gone too far.

The idea is that Earth’s climate went through a warming period just over 100,000 years ago that was similar in many ways to the warming now attributed to the actions of man. And the changes during that period were so catastrophic, they spawned massively powerful superstorms, causing violent ocean waves that simply lifted the boulders from below and deposited them atop this cliff.

If this is true, the agreements reached at the end of 2015 in Paris to hold the world’s nations to strict climate targets may be even more urgent than most people realize.

Hearty, an expert on Bahamas geology, first published in 1997 the idea that Cow and Bull were hurled to their perch by the sea. Since then, Hansen has given the work much added attention by framing the boulders as Exhibit A for his dire view of climate change — which has drawn doubters in the scientific community. But as Hansen examines the rocks on a recent morning, Hearty explains some of the evidence. In particular, Hearty points out that the tiny grains that constitute the boulder rocks are more strongly cemented together and less likely to crumble than other rocks nearby, a sign that the boulders are older than what’s beneath them.

“Yeah,” Hansen says with a nod, rubbing the younger rock and watching it crumble a little. He sees the difference. It’s a key point the two use to argue that the placement of these boulders indicates a dramatic hurling of the rocks by the sea. Even on a calm day, the deep blue waters of the Atlantic slam against the cliffs below with audible force and huge plumes of spray. But could waves have lifted these massive stones?

While there is a suggestion in the scientific literature that the boulders were simply left behind after surrounding rocks eroded away, Hearty and another leading Bahamas geology expert, Pascal Kindler of the University of Geneva in Switzerland, agree that the boulders are older than the surface upon which they rest and, thus, probably were moved by the sea. Even the tourist placard near here takes their side, saying the ocean “lifted them atop the ridge.” But exactly how it could have done that is another matter.

Scientists have tended to attribute odd boulders such as these to tsunamis — there’s little doubt they have the power to move large rocks. One recent study found that in the Cape Verde islands, 73,000 years ago, a 300-foot-high mega-tsunami carried boulders as large as 700 tons atop a cliff almost as high as the Eiffel Tower.

But more recent studies have also attributed large boulder movements to storms. And now into the fray has stepped Hansen, who, in 1988 testimony before Congress, put the climate issue on the map by contending — correctly, as it turned out — that global warming had already begun. If he is also right about the boulders, Earth could be in for a rough ride.

And even if not, one thing is clear: Cow and Bull present a scientific mystery whose solution may serve as a reminder of just how violent and dynamic a planet we live on.

The giant boulders known as “the Cow and the Bull” on the Bahaman island of Eleuthera. (Photo by Charles Ommanney)

Eleuthera in the Eemian

Hansen says he first encountered Hearty’s extensive Bahamas research — on the boulders and much more — eight years ago.

The two began to collaborate, and the result, once Hansen pulled in 15 other specialists as co-authors, was a 121-page paper presenting a dire reinterpretation of much of modern climate science.

In it, the researchers contend that there was a catastrophic storm event here 118,000 years ago. This would have occurred at the turbulent close of a climatic period sometimes dubbed the Eemian, which was moderately warmer than our own but featured considerably higher seas — especially at its end, when oceans appear to have risen quickly and then fallen again.

That period was one where, in Hansen’s interpretation, “all hell breaks loose”: a collapse of polar ice, quickly rising seas, a shutdown of heat-transporting ocean circulation, and then superstorms spawned by a greater temperature contrast between warm tropics and cold poles.

All of this is contested. While Hearty’s many geological studies of the Bahamas and its boulders have all been peer reviewed and published, the broader study remains under public peer review by a “discussion” journal, Atmospheric Chemistry and Physics Discussions. It has been the most downloaded paper the journal has ever considered, receiving one positive peer review and one skeptical one — and many assorted challenges.

Meanwhile, as the scientific debate continues, Hansen and Hearty last weekend met up in Eleuthera, accompanied by Hansen’s wife, Anniek, and his 17-year-old granddaughter, Sophie Kivlehan. Along with 21 other young people, Sophie is plaintiff to a lawsuit against the U.S. government — with Hansen playing the dual role of their guardian and scientific expert — demanding protection of their generation’s fundamental rights in the face of climate change.

It’s public moves such as this, or getting arrested protesting the Keystone XL oil pipeline, that have led some to contend that Hansen, scientific luminary though he is, has also become an “activist,” a label that makes many scientists uncomfortable.

Renowned climatologist James Hansen talks geology with researcher Paul Hearty. (Photo by Charles Ommanney)

Yet Eleuthera itself, and the large body of evidence Hearty presented as they toured it together, certainly implies that something dramatic happened in this landscape more than a hundred millennia ago.

Eleuthera, in the northeastern Bahamas, is home to about 11,000 people. There’s some tourism on the island, but it is also a geologist’s dream — a testament to the natural process that, over vast periods, generated layer upon layer of island rock from the simple sands formed offshore.

As seas rose here during warm interglacial periods such as the Eemian, the shallow coastal waters formed particles called “ooids,” tiny, egg-shaped sand grains of calcium carbonate. When seas fell again, these ooids rapidly hardened into limestone rock, preserving a detailed geologic record in the process. “Hot wax,” Hearty likes to call it.

Ooids from the Eemian formed much of present day Eleuthera, Hearty explains, and left behind hardened dunes and seashores considerably higher than current ocean levels. They also formed the rocks at the base of Cow and Bull, but the boulders themselves, he says, appear consistent with a far older cliff face that is well beneath them.

One simple demonstration: Hearty hits the boulders with his hammer. They ring loudly at the blows; the rocks beneath them sound more muffled — a hint, he says, that the boulders have had more time to harden than the younger formation below.

Another dating technique, called “amino acid racemization,” has also suggested the rocks’ older age. And then there are their “bedding planes,” or angular alignment of sediments within the rock. “The rock is tilted from any natural inclination, which means it was transported,” Hearty says.

Although the world of Bahamas geology is relatively small and sometimes contentious, Hearty is not the only researcher who thinks these rocks were moved by the ocean. The University of Geneva’s Kindler, who has examined the boulders and published with Hearty in the past — but also, notably, criticized his paper with Hansen — agrees that the boulders were put in their present location by giant waves.

“These boulders are much more weathered than the underlying substrate. The underlying substrate consists of very well-preserved limestone,” Kindler says. “They are partly dissolved, so they are older than their substrate.” However, Kindler holds that a localized tsunami, caused by an undersea landslide that would have occurred as the seafloor off the coast collapsed, is the most likely cause of the waves that threw the rocks.

The Twin Sisters boulder formation. (Photo by Charles Ommanney)

The ‘rages’

Seeing the boulders in their setting also makes it clear that along this stretch of coast, the deep Atlantic flings a tremendous amount of energy.

Slightly to the north of here, a high bridge connecting two parts of Eleuthera shows signs of repeated battering by huge waves (locals call them “rages”) that have shoved concrete barriers entirely off the road. Circa 1885, Winslow Homer painted this spot showing a high rock arch that framed a windowlike view of the sea. But now the arch is gone, “destroyed by a raging hurricane,” the tourist sign says.

Then, in addition to Cow and Bull, Hearty has documented five other boulders of similar size. Two lie in a curious, nearly straight line from Cow and Bull across a roughly 500-foot-wide stretch of the island. First comes another 1,000-ton boulder that Hearty calls Maverick. Entirely across the island, meanwhile, lie a pair of large rocks dubbed the Twin Sisters, sitting pristinely in the shallow and calm green waters of Eleuthera’s protected side. And there are three other large boulders nearby of similar sizes and features.

So what could have caused this? In his original 1997 paper, Hearty proposed three possible explanations: a tsunami, superstorms and Kindler’s preferred “bank margin collapse.” A tsunami could have come from afar or from a fluke event such as a meteor strike in the Atlantic, but a sub-sea landslide right off Eleuthera’s coast could also have displaced a large volume of water that surged back and threw boulders.

Hearty agrees there probably was such a collapse but asserts there is no evidence that it happened suddenly, rather than slowly or in smaller stages. Moreover, he sees other evidence of superstorms across Eleuthera and other parts of the Bahamas.

Farther inland in areas not protected by large cliffs, he thinks, the storms created curious chevron ridges, large V-shaped walls of rock sometimes extending several miles and always pointing to the southwest.

At very high heights on the islands, meanwhile, Hearty suggests that the huge waves left sediment layers featuring telltale beach bubbles, or fenestrae, suggesting waves reaching as much as 80 feet above the current sea level.

All of these features taken together, Hearty contends, are best explained by gigantic storms. He likes to invoke the principle of “parsimony,” meaning that the simplest explanation tends to be the right one. “It’s really the parsimony between the trilogy of evidence that makes this story hold together,” Hearty says.

Paul Hearty inspects rock on the island. His theory that ocean waves could have hurled boulders onto land is controversial, but he has convinced James Hansen, sometimes called “the father of global warming.” (Photo by Charles Ommanney)

Kindler disagrees that giant waves made the chevrons, however; he thinks they were assembled by winds. Hearty is “a good scientist, a good observer,” Kindler says. “But, yeah, I just do not agree with his interpretation.”

He is not the only skeptic. Mississippi State University’s John Mylroie, who has also conducted extensive research in the Bahamas, previously published the idea that Cow and Bull are remnant towers whose surrounding rock has eroded (an idea that Kindler and Hearty both reject). Mylroie is also skeptical of the storm interpretation. “The boulders on Eleuthera, if the result of wave-water action, represent a very narrow footprint that apparently occurred only once, which is not what you would expect for an increase in number of storms or storm intensities,” Mylroie says.

Hansen, though — the man who has helped make Hearty’s ideas famous — seems quite confident in them.

“We looked at those criticisms,” he says. And “it became all the clearer that the interpretation that we’re making is right, and that the boulders are wave-deposited, and highly likely that they’re deposited by the same storms that are causing the other obvious features in the Bahamas.”

The debate comes not only at a turbulent time in the climate discussion but also when growing evidence suggests that even today’s storms can move large boulders, an effect previously attributed more exclusively to tsunamis.

On Ireland’s Aran Islands, geologist Rónadh Cox of Williams College found that in intense North Atlantic storms in the winter of 2013 and 2014, more than 2,000 boulders moved, based on GPS mapping. Many were pretty small, but the biggest was over 400 tons.

Cox has not studied the Bahamas, but from her own work infers that Hearty’s ideas are a “valid hypothesis and one that can’t just be thrown out.”

Hearty contends that on Eleuthera, smaller boulders have moved within the past 12,000 years and may still be moving today. Not far from the mega-boulders, he shows Hansen a rocky plain strewn with boulders closer to 100 tons than 1,000. Hearty thinks this is the most storms can do in the modern era, which is why he thinks Eemian storms must have been stronger.

There is also the Philippine island of Samar, struck in 2013 by the extraordinarily intense super-typhoon Haiyan. Max Engel of the University of Cologne in Germany and his colleagues used satellite imagery to document the transport of numerous onshore boulders after the storm, including one that weighed 180 tons.

Storms, Engel says, “can create a boulder pattern that is very similar to what we would expect for tsunamis.”

People skeptical that ocean waves can move boulders are not thinking about the physics right, said Robert Weiss, a geophysicist at Texas A&M University. “The density of air is about a thousand times smaller than the density of water,” Weiss said. He added that a simple cubic meter of water, a cube that is a meter long on every side, already weighs a ton.

So when you start thinking about waves that are 25 or more feet high, traveling at speeds of over 10 mph, it’s not so odd to think of rocks moving. “That will cause significant damage. That will cause the movement of boulders,” Weiss said.

But for storms to fling boulders as big as those in the Bahamas, that would probably require an epic unleashing of energy. Hansen looks at the clues assembled by geologists such as Hearty and thinks that is what is in store for the planet if warming trends continue. That suggests not just a decades-long problem of rising ocean levels but also the potential for massive destruction.

“Unfortunately, it’s pretty clear that we are right,” Hansen said. He clearly believes it — and what is so troubling is that even many scientists who are skeptical can remember when he was right before.

The magic number

Holding warming under two degrees Celsius is the goal. But is it still attainable?

By Chris Mooney

The central goal of a United Nations’ climate conference held in Paris in late 2015 was to set the world on a path to ultimately restrict planetary warming to less than two degrees Celsius above preindustrial temperatures. The target was originally proposed by the European Union in the 1990s as a way to avert some of the worst consequences of climate change, such as rising sea levels.

But as ambitious as this effort is, time and math are working against it. Some scientists and analysts now suggest the two-degree target may be all but out of reach. The world has waited so long to cut emissions, they say, that sticking to two degrees may require extremely harsh cuts that could damage economies, or the assumption of future technologies that have not been invented yet.

Kevin Anderson, deputy director of the Tyndall Center for Climate Change Research at the University of Manchester in Britain, recently hurled a grenade into the two-degree discussion in an essay in Nature Geoscience by charging that many of his scientific colleagues “are ultimately choosing to censor their own research.”

Anderson particularly objects that many models now rely on “negative emissions” through technologies that remove carbon dioxide from the air or after combustion processes. These technologies, he objects, are at “little more than a conceptual stage of development.”

Oliver Geden, a researcher with the German Institute for International and Security Affairs, leveled similar charges earlier this year and has called for modifying the two-degree target, labeling it “patently unrealistic” and “obviously unattainable.” On the scientific front, meanwhile, a recent analysis by Stanford University earth scientist Rob Jackson and three colleagues found “without immediate and substantial mitigation . . . time has nearly run out for 2°C.”

And the goal is beset by other hurdles, too — such as major uncertainties surrounding how much carbon is really safe to emit, and around unexpected factors that can arise as the planet warms.

And then there’s the simple, discouraging fact that two degrees may not be a “safe” level of global warming anyway.

The ‘carbon budget’

The key problem is the finite global “carbon budget.” The two-degree goal was formally adopted by parties to the U.N. Framework Convention on Climate Change (UNFCCC) in a 2010 meeting in Cancun, Mexico, but it wasn’t until 2013 that a key innovation clarified the nature of the planetary emissions problem and showed how difficult it really is to solve.

This was the carbon budget.

Noting that the relationship between the amount of carbon dioxide we put in the atmosphere and the eventual global temperature is “near linear,” the United Nations’ Intergovernmental Panel on Climate Change calculated the maximum amount the world could emit for a one-third, 50 percent or two-thirds chance of keeping warming below two degrees.

The resulting headline: As of 2011, the world had about 1,000 gigatons, or billion metric tons, of carbon dioxide left to emit in order to have a two-thirds or greater chance of staying below two degrees. After that, net emissions must go to zero.

From here you simply do the math. Energy-related carbon dioxide emissions alone were 32.3 gigatons last year, according to the International Energy Agency, and that does not include other sources, such as deforestation. Based on such numbers, the remaining carbon budget is already under 900 gigatons of carbon dioxide.

Anderson’s paper calculated that once you take future deforestation and cement-related emissions between now and 2100 into account, the remaining budget is just 650 gigatons of energy-related emissions. That’s about 20 years at current rates — but emissions are still rising. That trend is currently expected to continue out to 2025 or 2030, despite countries’ recent carbon-cutting pledges, in large part because of growing demand for energy in coming decades.

The UNFCCC recently acknowledged that these pledges, on their own, would hold warming to perhaps only 2.7 degrees Celsius — other analyses are still more pessimistic — and, therefore, that much more must be done in Paris and beyond to ensure attainment of the two-degree goal.

And, of course, that’s assuming that we’re using the right number to begin with: There are big error bars around the 1,000-gigaton number. “When we talk about a thousand billion tons left with a probability of 66 percent, we’re saying we think that budget, there is 1 in 3 probabilities that you’ll still go beyond,” said Pep Canadell, executive director of the Global Carbon Project and a scientist at Australia’s Commonwealth Scientific and Industrial Research Organization.

In one recent paper, Canadell, Jackson and two colleagues found that a 90 percent probability shrinks the allowable carbon budget by 500 gigatons — and that we would bust such a budget in about a decade.

The permafrost problem

And there are still more issues. For instance, scientists have recently verified a long-standing fear — that as warming increases, the thawing of northern permafrost, frozen soil that contains the remains of dead but un-decomposed plant life, will steadily release carbon into the air. It is not clear how fast or how much, but one recent study found that for moderate warming of 1.2 additional degrees Celsius between the year 2010 and 2100, global permafrost could emit 44.8 to 122.6 gigatons of carbon dioxide, which would tighten the carbon budget further.

More generally, scientists do not fully understand the global carbon cycle, which governs the ultimate fate of all the CO2 we put in the atmosphere. Any revisions in our understanding of how much carbon gets taken up by the ocean or by trees and plants would also require revisions to carbon budgets.

And this does not even address the deepest problem — whether two degrees is actually the right threshold to avoid “dangerous” climate change, a term that comes from the UNFCCC, the international treaty at the center of these negotiations.

In the end, the definition of “safety” is subjective. But recent research suggests that for every degree of warming, the world can ultimately expect to see about 2.3 meters (over seven feet) of gradual, long-term sea-level rise. No wonder many countries — though not the big emitters, such as the United States and China — are holding out for a target of 1.5 degrees Celsius rather than two degrees.

But not unlike the 90-percent-or-greater chance of staying under two degrees, the carbon budget for 1.5 degrees is much tighter. “I think 1.5 degrees is gone,” Anderson says.

One way to improve these odds is to assume that in the future we will be able to “take back” emissions that we’ve put in the atmosphere — “negative emissions.”

“Negative emissions, in my mind, fall somewhere between a godsend and voodoo,” said Stanford’s Jackson. “The advantage is that it allows us to overshoot targets, then come back down. The disadvantage is, we don’t know that it’s going to work, and we’re not sure how much people are going to be willing to pay for it even if it could work.”

The leading candidate for negative emissions is bioenergy combined with carbon capture and sequestration, or BECCS. The idea is that we would burn trees or biomass to create energy, which would grow again and store carbon, making the process carbon neutral. But if we also sequestered the carbon from burning biomass in the ground, the result would be a net removal of the gas from the atmosphere.

Anderson charges that current two-degree scenarios rely heavily on this concept. “I have no problem with one or two scenarios, or 10 percent of all scenarios having some BECCS in them,” he said. “But once you start to have 80 or 90 or 100 percent of their scenarios having BECCS, that’s a systemic bias.”

Tech assumptions

The U.N. Environment Program recently released a report confirming this concern. It noted that scenarios that are able to keep warming to two degrees, without major emissions cuts before the year 2020, “rely on so-called ‘negative emission technologies.’ ”

Although this kind of technology does not exist in any widespread form, researchers are certainly interested in exploring it. “I think the pieces individually work. Carbon capture today works technically, although not economically, yet,” said Dan Kammen, an energy policy expert at the University of California at Berkeley who has published on the subject. “The pieces are all there, and because it does look like we are going to need carbon-negative energy, there’s a big upside in exploring the options.”

KEVIN ANDERSON, deputy director of the Tyndall Center for Climate Change Research at the University of Manchester in Britain. Two degrees “only remains a viable goal if we are prepared to accept the implications.”

There is also the prospect of directly capturing carbon from the air. The firm Carbon Engineering, with funding from Bill Gates, just opened an experimental carbon-capture plant in Squamish, B.C., that can capture “a couple of tons of CO2 per day,” said chief executive Adrian Corless. Scaling that up would, obviously, be a gigantic endeavor. But Corless expects the world will need the technology more in the future and be willing to pay for it — especially in light of “negative emissions” scenarios.

And there’s another glint of good news, Jackson said — rapid growth rates for wind and solar. “We built 50 gigawatts of new wind capacity last year,” he said. “That is more than was on the planet a decade ago.” Still, most scenarios assume only a gradual displacement of carbon-intensive fossil fuels such as coal from the global energy supply.

So despite the call for action in Paris, there are rising questions about two degrees and about negative emissions in particular. The prospects for staying within the carbon budget are not gone, because the budget-busting emissions literally have not gone into the air yet. But with every year and, indeed, every day, the quest gets harder.

Two degrees, Anderson said, “only remains a viable goal if we are prepared to accept the implications.”

More from The Washington Post…

Get the latest news and essential information directly in your inbox from The Washington Post.
Sign up for free e-newsletters and alerts.

Connect with The Washington Post on Twitter @washingtonpost and on Facebook.

Learn more about The Washington Post Series:

Connect with Diversion Books

Connect with us for information on new titles and authors from Diversion Books, free excerpts, special promotions, contests, and more: