Field Notes From a Catastrophe: Man, Nature, and Climate Change (20 page)

But it’s also possible to take an even longer view of the situation. The climate record provided by Greenland ice cores gives a highly resolved history going back more than a hundred thousand years and the Antarctic cores a history stretching back more than four hundred thousand years. What these records show, in addition to a clear correlation between CO
₂
levels and global temperatures, is that the last glaciation was a time of frequent and traumatic climate swings. During that period, humans who were, genetically speaking, just like ourselves wandered the globe, producing nothing more permanent than isolated cave paintings and large piles of mastodon bones. Then, ten thousand years ago, the weather changed. As the climate settled down, so did we. People built villages, towns, and, finally, cities, along the way inventing all the basic technologies—agriculture, metallurgy, writing—that future civilizations would rely upon. These developments would not have been possible without human ingenuity, but, until the climate cooperated, ingenuity, it seems, wasn’t enough.

Ice core records also show that we are steadily drawing closer to the temperature peaks of the last interglacial, when sea levels were some fifteen feet higher than they are today. Just a few degrees more and the earth will be hotter than it has been at any time since our species evolved. The feedbacks that have been identified in the climate system—the ice-albedo feedback, the water vapor feedback, the feedback between temperatures and carbon storage in the permafrost—take small changes to the system and amplify them into much larger forces. Perhaps the most unpredictable feedback of all is the human one. With six billion people on the planet, the risks are everywhere apparent. A disruption in monsoon patterns, a shift in ocean currents, a major drought—any one of these could easily produce streams of refugees numbering in the millions. As the effects of global warming become more and more difficult to ignore, will we react by finally fashioning a global response? Or will we retreat into ever narrower and more destructive forms of self-interest? It may seem impossible to imagine that a technologically advanced society could choose, in essence, to destroy itself, but that is what we are now in the process of doing.

Afterword

This book was written at a moment when the evidence of global warming was becoming overwhelming, yet the American political system seemed incapable of acknowledging the problem. In the years since then, a lot has happened. Hurricane Katrina devastated New Orleans. Al Gore and the members of the Intergovernmental Panel on Climate Change were jointly awarded the Nobel Peace Prize. The United State selected a new president who promised that combating climate change would be “a leading priority” of his administration. In an ABC News poll taken shortly before Barack Obama’s inauguration, three quarters of the respondents said they thought he should “implement policies to try to reduce global warming.” No longer a fringe issue, climate change has become a central concern for millions of Americans.

This shift is encouraging, and I would like to be able to write that, as a result, I now feel more optimistic about our situation. Sadly, the opposite is the case.

I completed this book late in 2005. That year now ranks as the warmest on record, according to NASA’s Goddard Institute for Space Studies, and every year since then has ranked among the ten warmest. Meanwhile, hundreds—perhaps thousands—of new studies on climate change have appeared. A disturbingly large proportion of them point to the same conclusion: the world is changing more rapidly and more dramatically than had been anticipated. “In nearly all areas, the developments are occurring more quickly than had been assumed,” Hans Joachim Schellnhuber, the head of Germany’s Potsdam Institute for Climate Impact Research, recently observed. “We are on our way to a destabilization of the world climate that has advanced much further than most people or their governments realize.”

Consider, for example, what has happened to the Arctic sea ice. In September 2005, at the end of the summer melt season, satellite measurements showed that the extent of the ice cap had shrunk to the lowest level on record. The loss of ice was so great that it prompted scientists to revise their forecasts. While earlier they had predicted the Arctic Ocean could be ice-free in summer by 2080, their new prediction was that the perennial ice cap could disappear “well before the end of this century.” Then, in September 2007, another dramatic new low was set; in just two years, the ice cap had shrunk by an additional—and astonishing—23 percent. For the first time in human memory, a navigable Northwest Passage was open. Once again, scientists were forced to revise their forecasts. NASA’s Jay Zwally (with whom I shared a snowmobile at Swiss Camp) predicted that the Arctic ice cap would be very nearly gone by the summer of 2012.

“The Arctic is often cited as the canary in the coal mine for climate warming,” Zwally said. “Now, the canary has died.”

The extent of perennial Arctic sea ice has continued to shrink dramatically. The rate of decline since 1979 is nearly 12 percent per decade. Credit: National Snow and Ice Data Center, 2008

Hardly less compelling have been recent observations from Antarctica and Greenland. In 2006, a team of researchers analyzing data from satellites that measure tiny changes in the earth’s gravitational pull concluded that Antarctica has been losing ice at the rate of roughly thirty-six cubic miles per year. That same year, scientists from NASA and the University of Kansas announced that the flow of ice from glaciers in Greenland had more than doubled over the past decade. These findings were particularly significant because most models had predicted that the ice sheets would
gain
mass over the next several decades, owing to increased snowfall at their centers. “We’re now one hundred years ahead of schedule,” Richard Alley, a glaciologist at Penn State, has observed. Shortly before he set off for his seventeenth field season at Swiss Camp, Konrad Steffen spoke to me about the latest Greenland data. He said that changes on the ice sheet were occurring an order of magnitude faster than he had been taught to expect. If the trends are not sustained, “then we have a problem,” he told me. If they are sustained, “then we have a deep problem.”

Since ice loss from Greenland and Antarctica translates into rising sea levels, these estimates, too, have had to be revised. When I was writing this book, sea levels were expected to rise by a maximum of three feet by the end of the century. That figure has now doubled—the maximum is currently estimated to be close to six feet. In the fall of 2008, a commission appointed by the Dutch government warned that owing to rising sea levels, the Netherlands would have to spend 100 billion euros—roughly $140 billion—to reinforce its dikes.

In 2005, the threat posed by rising CO
₂
levels was discussed almost exclusively in terms of life on land. It has since become clear that carbon dioxide also poses a very substantial danger to life in the sea.

Ocean covers 70 percent of the earth’s surface, and everywhere that water and air come into contact there is an exchange. Gases from the atmosphere are absorbed by the ocean and gases dissolved in the water are released into the atmosphere. When the two are in equilibrium, roughly the same quantities are being dissolved as are getting released. But because CO
₂
levels have been rising so quickly, the exchange has become lopsided: more CO
₂
from the air is entering the water than comes back out.

When CO
₂
dissolves, it produces carbonic acid—H
₂
CO
_3.
As acids go, H
₂
CO
₃
is relatively innocuous—we drink it all the time in Coke and other carbonated beverages—but in sufficient quantities it can change the water’s pH. Already, enough carbon has entered the oceans to produce a .1 decline in surface pH. (Of the 250 billion metric tons of carbon that we have poured into the atmosphere since the start of the industrial revolution, nearly half have been absorbed by the oceans.) Since pH, like the Richter scale, is a logarithmic measure, a .1 drop represents a rise in acidity of about 30 percent. The process is generally referred to as “ocean acidification.”

For a variety of reasons, including the slow pace of deep ocean circulation, it is impossible to reverse the acidification that has already taken place. Nor is it possible to prevent still more from occurring. Even if there were some way to halt CO
₂
emissions tomorrow, the oceans would continue to take up carbon until they reached a new equilibrium with the air. As Britain’s Royal Society has noted, it will take “tens of thousands of years for ocean chemistry to return to a condition similar to that occurring at pre-industrial times.”

How marine life will respond to this change in ocean chemistry is not yet clear. But the experimental evidence gathered so far is alarming. Most marine organisms that build shells or, as is the case with corals, calcareous skeletons, construct them out of calcium carbonate—CaCO
₃
. Adding carbonic acid to the oceans reduces the number of carbonate ions available, making the organisms’ task that much more difficult. (The process might be compared to trying to build a house while someone keeps stealing the bricks.) If current emissions trends continue, it’s estimated that sometime around the middle of the century coral growth will slow to the point that reefs will no longer be able to keep up with their predators. They will start to disappear, and this, in turn, will threaten the many organisms that depend on them for survival.

“Being conservative, let’s say it’s a million species that live in and around coral,” Ove Hoegh-Guldberg, an expert on reefs at the University of Queensland, in Australia, told me. “Some of these species that hang around coral reefs can sometimes be found living without coral. But most species are completely dependent on coral—they literally live in, eat, and breed around coral. The key question is how vulnerable all these various species are. That’s a very important question, but at the moment you’d have to say that a million different species are under threat.”

Calcifying organisms come in a fantastic array of shapes, sizes, and taxonomic groups. Echinoderms like starfish are calcifiers. So are mollusks like clams and oysters, and crustaceans like barnacles, and many species of bryozoans, or sea mats. As with coral, many of these calcifiers are likely to be in trouble as ocean pH declines. If carbonate levels fall far enough, the water becomes corrosive, and shells beg into dissolve. (Imagine putting a piece of chalk in a bowlful of vinegar.) Such “undersaturated” conditions are expected to appear first near the poles, because carbon dioxide dissolves more readily in cold water. Models had projected that under a “business as usual” scenario the Southern Ocean, around Antarctica, would become undersaturated sometime around the middle of the century. However, a recent study by Australian scientists suggests that the Southern Ocean could become undersaturated much sooner than that, perhaps within the next two decades.

Just as we have understated the dangers of rising CO
₂
, so, too, have we underestimated the rate at which CO
₂
levels would rise. Global emissions grew from six gigatons of carbon per year in 1990 to eight and a half gigatons in 2007, an increase of nearly 40 percent. This growth rate exceeded the most carbon-intensive projections used by the Intergovernmental Panel on Climate Change, making current trends in emissions higher than the IPCC’s worst-case scenario. Much of the increase was a product of rapid emissions growth from China, which is believed to have to overtaken the United States as the world’s largest generator of CO
₂
in 2008, nearly two decades ahead of schedule. But emissions also grew in most other parts of the world, including here in America. At the same time, according to a report by the Global Climate Project, an international research group, natural carbon “sinks,” like the oceans, are becoming less efficient, meaning they are removing a smaller proportion of emissions from the atmosphere.

“All of these changes,” the report noted, “characterize a carbon cycle that is generating stronger climate forcing and sooner than expected.”

What should we do with such information? Over the past four years, I’ve talked with a lot of people who are trying to translate what they know into constructive action. I traveled to the Danish island of Samsø, where I spoke to farmers who have erected wind turbines in their fields and rigged their tractors to run off canola oil. (Samsø is one of the few places in the world that can genuinely claim to be carbon neutral; it generates the equivalent of all the energy that it uses from wind and other renewable sources.) I went to Switzerland to meet with scientists who have devised a blueprint for sustainable energy use called the 2,000-Watt Society. I interviewed Amory Lovins, the “guru” of energy conservation, and Van Jones, who’s been described as the “Martin Luther King of the green jobs movement.” While I was inspired by these visits, nothing that I saw or heard was remotely commensurate with the problem. (The 2,000-Watt Society, for example, exists only on paper.)