|
Nowhere is the impact of dramatic climate shift more evident than in the Arctic, where even the Godzilla of Global Warming Foot Dragging, the Bush Administration, has had to admit that melting ice threatens the polar bear with extinction. But ice-melting horror shows are playing in other theaters, too—from the ice sheets in Greenland and Antarctica to the permafrost of Siberia, from Glacier National Park to the snow cap on Kilimanjaro. The planet has become the Wicked Witch of the West—"I'm mellllting!"
Today's article gives an overview of the global warming/melting ice issue. It's the third in a four-part series of excerpts that Grinning Planet is running from Lester Brown's excellent book, Plan B 3.0—Mobilizing to Save Civilization.
~ ~ ~
Rising Temperatures and Rising Seas,
by Lester R. Brown, Earth Policy Institute
Civilization has evolved during a period of remarkable climate stability, but this era is drawing to a close. We are entering a new era, a period of rapid and often unpredictable climate change. The new climate norm is "change."
In 2007, the Intergovernmental Panel on Climate Change (IPCC)—the world's official "global warming science agency," which includes more than 2,500 top scientists from around the world—released a consensus report affirming humanity's role in climate change and projecting that the earth's average temperature will rise 2.0-11.5 degrees Fahrenheit (1.1-6.4 degrees Celsius) during this century.
This projected rise is a global average. In reality, the rise will be very uneven—much greater over land than over oceans, greater in the high northern latitudes (including the poles) than over the equator, and greater in the continental interiors than in coastal regions.
In the spring of 2007, while giving a lecture at Kyoto University, I noted that there had been a remarkable shift during the decade since the Kyoto Protocol was negotiated. In 1997, climate change was discussed in the future tense. Today we discuss it in the present tense. It is no longer something that may happen. It is happening now.
Snow and ice masses in mountains are nature's freshwater reservoirs—nature's way of storing water to feed rivers during the dry season, providing irrigation and drinking water to hundreds of millions. Now they are being threatened by the rise in temperature. Even a 1-degree rise in temperature in mountainous regions can markedly reduce the share of precipitation falling as snow and boost that coming down as rain.
While the glaciers are melting, river flows are often above normal, which increases flooding during the rainy season. Once the glaciers are gone or reduced to insignificant size, river flows will drop sharply, reducing the snowmelt flow into rivers during the drier part of the year. Some glaciers have already disappeared entirely.
China and India
Nowhere is the melting of glaciers of more concern than in Asia, where 1.3 billion people's water supply depends on rivers originating in the Himalayan Mountains and the adjacent Tibet-Qinghai Plateau.
India's Gangotri Glacier, which supplies 70 percent of the water to the Ganges, is not only melting, it is doing so at an accelerated rate. If this melting continues to accelerate, the Gangotri's life expectancy will be measured in decades and the Ganges will become a seasonal river, flowing only during the rainy season. For the 407 million Indians and Bangladeshis who live in the Ganges basin, this could be a life-threatening loss of water.
In China, which is even more dependent than India on river water for irrigation, the situation is particularly challenging. Chinese government data show the glaciers on the Tibet-Qinghai Plateau that feed both the Yellow and Yangtze Rivers are melting at 7 percent a year. The Yellow River, whose basin is home to 147 million people, could experience a large dry-season flow reduction. The Yangtze River, by far the larger of the two, is threatened by the disappearance of glaciers as well. The basin's 369 million people rely heavily on rice from fields irrigated with Yangtze River water.
Yao Tandong, a leading Chinese glaciologist, predicts that two thirds of China's glaciers could be gone by 2060. "The full-scale glacier shrinkage in the plateau region," Yao says, "will eventually lead to an ecological catastrophe."
The world has never faced such a predictably massive threat to food production as that posed by the melting mountain glaciers of Asia. China and India are the world's leading producers of both wheat and rice—humanity's food staples. China's wheat harvest is nearly double that of the United States, which ranks third after India. With rice, these two countries are far and away the leading producers, together accounting for over half of the world harvest.
Elsewhere in Asia and the Near East
Other Asian rivers that originate in this "rooftop of the world" include the Indus, with 178 million people in its basin in India and Pakistan; the Brahmaputra, which flows through Bangladesh; and the Mekong, which waters Cambodia, Laos, Thailand, and Viet Nam.
Agricultural activities in the Central Asian countries of Afghanistan, Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, and Uzbekistan depend heavily on snowmelt from the Hindu Kush, Pamir, and Tien Shan mountain ranges. Nearby Iran gets much of its water from the snowmelt in the 5,700-meter-high Alborz Mountains between Tehran and the Caspian Sea.
Africa
In Africa, Tanzania's snow-capped Kilimanjaro may soon be snow- and ice-free. Ohio State University glaciologist Lonnie Thompson's studies of Kilimanjaro show that Africa's tallest mountain lost 33 percent of its ice field between 1989 and 2000. He projects that its snowcap could disappear entirely by 2015. Nearby Mount Kenya has lost 7 of its 18 glaciers. Local rivers fed by these glaciers are becoming seasonal rivers, generating conflict among the 2 million people who depend on them for water supplies during the dry season.
South America
Bernard Francou, research director for the French government's Institute of Research and Development, believes that 80 percent of South American glaciers will disappear within the next 15 years. For countries like Bolivia, Ecuador, and Peru, which rely on glaciers for water for household and irrigation use, this is not good news.
Peru, which stretches some 1,600 kilometers along the vast Andean mountain range and which is home to 70 percent of the earth's tropical glaciers, is in trouble. Some 22 percent of its glacial endowment, which feeds the many Peruvian rivers that supply water to the cities in the semi-arid coastal regions, has disappeared. Lonnie Thompson reports that the Quelccaya Glacier in southern Peru, which was retreating by 6 meters per year in the 1960s, is now retreating by 60 meters annually. Many of Peru's farmers irrigate their wheat and potatoes with the river water from these disappearing glaciers. During the dry season, farmers are totally dependent on irrigation water. For Peru's 28 million people, shrinking glaciers will eventually mean a shrinking food supply.
Europe
In the Caucasus Mountains in Russia, glacial volume declined by 50 percent in the twentieth century.
Alpine glaciers in the Tyrol Province, Austria are retreating an average of 3 percent per year. Alpine glaciers are likely to contain only half their 1970s volume by 2025, dwindling to 5 percent by the end of the century.
United States
Out of 2,000 glaciers in southeast Alaska, 1,987 are retreating. Since the mid-1990s, Alaskan glaciers have been thinning by 1.8 meters a year, over three times as fast as during the preceding 40 years.
Glacier National Park in the Rocky Mountains has seen about 75 percent of its glacier area disappear since 1910. Remaining glaciers may melt completely by 2030.
In many US agricultural regions, snow and ice masses are the leading source of irrigation and drinking water. In the southwestern US, for instance, the Colorado River—the region's primary source of irrigation water—depends on snowfields in the Rockies for much of its flow. California, in addition to depending heavily on the Colorado, also relies on snowmelt from the Sierra Nevada in the eastern part of the state. Both the Sierra Nevada and the coastal range supply irrigation water to California's Central Valley, the world's fruit and vegetable basket.
Preliminary results of an analysis of rising temperature effects on three major river systems in the western United States—the Columbia, the Sacramento, and the Colorado—indicate that the winter snow pack in the mountains feeding them will be dramatically reduced and that winter rainfall and flooding will increase.
A detailed study of the Yakima River Valley, a vast fruit-growing region in Washington state, conducted by the US Department of Energy shows progressively heavier harvest losses as the snow pack shrinks, reducing irrigation water flows. With a business-as-usual energy policy, global climate models project an overall 70 percent reduction in the amount of snow pack for the western United States by mid-century.
Overall Risk
The snow and ice masses in the world's leading mountain ranges and the water they store are taken for granted simply because they have been there since before agriculture began. Now that is changing. If we continue raising the earth's temperature, we risk losing the reservoirs in the sky on which cities and farmers depend.
The complete melting of the ice sheets of Greenland and West Antarctica would cause sea levels to rise 39 feet (12 meters), leaving many of the world's coastal cities underwater; with over 600 million coastal dwellers displaced. But even partial melting of these ice sheets will have a dramatic effect on sea level rise.
The IPCC 2007 report projected that sea levels would rise during this century by 1-2 feet. Senior scientists are noting that these estimates are already obsolete—a rise of 6 feet during this time is within range.
The Arctic
A study conducted by the Arctic Climate Impact Assessment (ACIA) team, an international group of 300 scientists, found that in the regions surrounding the Arctic, including Alaska, western Canada, and eastern Russia, winter temperatures have already climbed by 4-7 degrees Fahrenheit (3-4 degrees Celsius) over the last half-century. Robert Corell, chair of ACIA, says this region "is experiencing some of the most rapid and severe climate change on Earth."
In testimony before the U.S. Senate Commerce Committee, Sheila Watt-Cloutier, an Inuit speaking on behalf of the 155,000 Inuits who live in Alaska, Canada, Greenland, and the Russian Federation, described their struggle to survive in the fast-changing Arctic climate as "a snapshot of what is happening to the planet." She called the warming of the Arctic "a defining event in the history of this planet."
The ACIA report described how the retreat of the sea ice has devastating consequences for polar bears, whose very survival may be at stake. A subsequent report indicated that polar bears, struggling to survive, are turning to cannibalism. Also threatened are ice-dwelling seals, a basic food source for both the bears and the Inuit.
Since this 2005 report, there is new evidence that the problem in the Arctic is worse than previously thought. A team of scientists from the National Snow and Ice Data Center and the National Center for Atmospheric Research, which has compiled data on Arctic Ocean summer ice melting from 1953 to 2006, concluded that the ice is melting much faster than climate models had predicted. They found that from 1979 to 2006 the summer sea ice shrinkage accelerated to 9.1 percent per decade.
Average September Arctic Ocean Sea Ice Extent, 1979-2007
SOURCE: NSIDC via Earth Policy Institute
In the summer of 2007, Arctic sea ice set a new record low—20 percent below the previous record set in 2005. This suggests that the sea could be ice-free well before 2050, the earliest date projected by the IPCC in its 2007 report. Some scientists now think that the Arctic Ocean could be ice-free in the summer as early as 2030.
|
Arctic scientist Julienne Stroeve observes that the shrinking Arctic sea ice may have reached "a tipping point that could trigger a cascade of climate change reaching into Earth's temperate regions." Walt Meier, a researcher at the US National Snow and Ice Data Center who tracks the changes in Arctic sea ice, views the winter shrinkage with alarm. He believes there is "a good chance" that the Arctic tipping point has been reached. "People have tried to think of ways we could get back to where we were. We keep going further and further in the hole, and it's getting harder and harder to get out of it."
Greenland
Several recent studies report that the melting of the Greenland ice sheet is accelerating. A study published in Science in 2006 reported that the rate of ice melt on the vast island has tripled over the last several years. That same month a University of Colorado team published a study in Nature indicating that between 2004 and 2006 Greenland lost ice at a rate 2.5 times that of the preceding two years.
In 2006, a team of NASA scientists reported that the flow of glaciers into the sea was accelerating. Eric Rignot, a glaciologist at NASA's Jet Propulsion Laboratory, said, "None of this has been predicted by numerical models, and therefore all projections of the contribution of Greenland to sea level [rise] are way below reality."
Feedback Loops and Melting Ice Caps
Scientists are concerned that "positive feedback loops"—trends that reinforce themselves—may be starting to kick in for both the Arctic and Greenland. Two of these potential feedback mechanisms are of particular concern to scientists.
|
|
MORE ICY TRUTH |
|
THE ARCTIC
The percentage of the Arctic Ocean with stable (perennial) ice cover has decreased from more than 50% in the mid-1980s to less than 30% as of 2008. The area of thick Arctic ice lost over the past two decades is 1.5 times the size of Alaska. (SOURCE: The Washington Post -- includes good before-and-after graphic)
GREENLAND
In Greenland, research has shown that even minor amounts of surface melt lead to large amounts of ice mass loss. Dorothy Hall, a senior researcher at NASA's Goddard Space Flight Center, explained: "We're seeing a close correspondence between the date that surface melting begins and the date that mass loss of ice begins beneath the surface," Hall said. "This indicates that the meltwater from the surface must be traveling down to the base of the ice sheet—through over a mile of ice—very rapidly, where its presence allows the ice at the base to slide forward, speeding the flow of outlet glaciers that discharge icebergs and water into the surrounding ocean." (SOURCE: NASA/Goddard Space Flight Center via ENN)
ANTARCTICA
A study led by NASA's Jet Propulsion Laboratory and the University of California showed that the Antarctic ice sheet is melting faster than previously anticipated, with the rate doubling between 2006 and 1996. In 2008, scientists observed that the huge Wilkins ice shelf is on the verge of disintegration. The European Space Agency says the Wilkins shelf—the largest to be threatened so far—is "hanging by its last thread." (SOURCES: ENN, The Independent)
GLACIERS
While most of the long-term threat of rising seas comes from melting ice in Greenland and Antarctica, the big threat this century could come from thawing glaciers, which are melting even faster than the remote ice sheets. Even though glaciers contain only 1/100 the volume of fresh water in Antarctic and Greenland ice, they could account for almost a foot of sea level rise by 2100. With 100 million people living within a few feet of sea level, a one-foot glacier-driven rise—plus additional rise due to the melting ice sheets and the oceans' thermal expansion—will likely present a significant problem. (SOURCE: Reuters)
--
|
|
The first is the albedo effect. When incoming sunlight strikes the ice in the Arctic Ocean, up to 70 percent of it is reflected back into space. Only 30 percent is absorbed as heat. As the Arctic sea ice melts, however, and the incoming sunlight hits the much darker open water, only 6 percent is reflected back into space and 94 percent is converted into heat. This may account for the accelerating shrinkage of the Arctic sea ice and the rising regional temperature.
|
If all the ice in the Arctic Ocean melts, it will not affect sea level because the ice is already in the water. But it will lead to a much warmer Arctic region as more of the incoming sunlight is absorbed as heat. This is of particular concern because Greenland lies largely within the Arctic Circle. As the Arctic region warms, Greenland's ice sheet—up to 1 mile (1.6 kilometers) thick in places—is beginning to melt. This will cause sea level rise—of up to 23 feet (7 meters).
|
TAKING THE "PERM"
OUT OF PERMAFROST |
|
As permafrost thaws, it releases large quantities of the potent greenhouse gas methane, thus creating a reinforcing feedback loop: more methane = more greenhouse gases = more warming = more thawing = more methane. Methane emissions from thawing permafrost in Northern Siberia increased an estimated 58 percent between 1974 and 2000.
--
|
|
The second positive feedback mechanism also has to do with how ice melts. What scientists once thought was a fairly simple linear process—that is, a certain amount at the surface of an ice sheet melts each year, depending on the temperature—is now seen to be much more complicated. As the surface ice begins to melt, some of the water filters down through cracks in the glacier, lubricating the surface between the glacier and the rock beneath it. This accelerates the glacial flow and the calving of icebergs into the surrounding ocean. The relatively warm water flowing through the glacier also carries surface heat deep inside the ice sheet far faster than it would otherwise penetrate by simple conduction.
Antarctica
At the other end of the earth, the 2-kilometer-thick Antarctic ice sheet, which covers a continent about twice the size of Australia and contains 70 percent of the world's fresh water, is also beginning to melt. Ice shelves that extend from the continent into the surrounding seas are starting to break up at an alarming pace.
In May 2007, a team of scientists from NASA and the University of Colorado reported satellite data showing widespread snow-melt on the interior of the Antarctic ice sheet over an area the size of California. This melting in 2005 was 900 kilometers inland, only about 500 kilometers from the South Pole. Konrad Steffen, one of the scientists involved, observed, "Antarctica has shown little to no warming in the recent past with the exception of the Antarctic Peninsula, but now large regions are showing the first signs of the impacts of warming."
The ice shelves surrounding Antarctica are formed by the flow of glaciers off the continent into the surrounding sea. This flow of ice, fed by the continuous formation of new ice on land and culminating in the breakup of the shelves on the outer fringe and the calving of icebergs, is not new. What is new is the pace of this process. When Larsen A, a huge ice shelf on the east coast of the Antarctic Peninsula, broke up in 1995, it was a signal that all was not well in the region. Then in 2000, a huge iceberg nearly the size of Connecticut broke off the Ross Ice Shelf.
After Larsen A broke up, it was only a matter of time, given the rise in temperature in the region, before neighboring Larsen B would do the same. So when the northern part of the Larsen B ice shelf collapsed into the sea in March 2002, it was not a total surprise. At about the same time, a huge chunk of ice broke off the Thwaites Glacier. Covering 5,500 square kilometers, this iceberg was the size of Rhode Island.
Even veteran ice watchers are amazed at how quickly the disintegration is occurring. "The speed of it is staggering," said Dr. David Vaughan, a glaciologist at the British Antarctic Survey, which has been monitoring the Larsen Ice Shelf closely. Along the Antarctic Peninsula, in the vicinity of the Larsen Ice Shelf, the average temperature has risen 4.6 degrees F (2.5 degrees C) over the last five decades.
When ice shelves already largely in the water break off from the continental ice mass, this does not have much direct effect on sea level per se. But without the ice shelves to impede the flow of glacial ice, typically moving 400-900 meters a year, the flow of ice from the continent could accelerate, leading to a thinning of the ice sheet on the edges of the Antarctic continent. If this were to happen, sea level would rise accordingly.
Sea Level Rise
The International Institute for Environment and Development (IIED) has analyzed the effect of a 10-meter rise in sea level, providing a sense of what the melting of the world's largest ice sheets could mean. The IIED study begins by pointing out that 634 million people live along coasts at or below 10 meters above sea level, in what they call the Low Elevation Coastal Zone. This massive vulnerable group includes one eighth of the world's urban population.
One of the countries most vulnerable is China, with 144 million potential climate refugees. India and Bangladesh are next, with 63 and 62 million respectively. Viet Nam has 43 million vulnerable people, and Indonesia, 42 million. Others in the top 10 include Japan with 30 million, Egypt with 26 million, and the United States with 23 million.
The world has never seen such a massive potential displacement of people. Some of the refugees could simply retreat to higher ground within their own country. Others—facing extreme crowding in the interior regions of their homeland—would seek refuge elsewhere. Bangladesh, already one of the world's most densely populated countries, would face a far greater concentration: in effect, 62 million of its people would be forced to move in with the 97 million living on higher ground. Would a more sparsely populated country like the United States be willing to accommodate an influx of rising-sea refugees while it was attempting to relocate 23 million of its own citizens?
Not only would some of the world's largest cities, such as Shanghai, Kolkata, London, and New York, be partly or entirely inundated, but vast areas of productive farmland would also be lost. The rice-growing river deltas and floodplains of Asia would be covered with salt water, depriving Asia of part of its food supply. This loss of prime farmland would parallel the loss of river water as Himalayan glaciers disappear.
In the end, the question is whether governments are strong enough to withstand the political and economic difficulties associated with relocating large numbers of people while suffering losses of housing and industrial facilities. The relocation is not only an internal matter, since a large share of the displaced people will want to move to other countries. Can governments withstand these stresses, or will more and more states fail?
The overall impact of global climate change will reach beyond just rising seas and reduced river flows. The destructive effects of higher temperatures are visible on many fronts, from reduced agricultural yields to migration of vector-based diseases like malaria to an increase in the number of highly destructive Category 5 hurricanes.
Researchers such as NASA's James Hansen believe that global warming is accelerating and may be approaching a tipping point—a point at which climate change acquires a momentum that makes it irreversible. They think we may have a decade to turn the situation around before this threshold is crossed.
If we allow the climate to spin out of our control, we risk huge financial costs. Former World Bank chief economist Nicholas Stern has projected that the long-term costs of climate change could exceed 20 percent of gross world product (GWP). By comparison, the near-term costs of cutting greenhouse gas emissions to stabilize climate, which Stern estimates at 1 percent of GWP, would be a bargain.
We often hear descriptions of what we need to do "in the decades ahead" or "by 2050" to avoid dangerous climate change. But we are already facing dangerous climate change. So in Plan B we propose an all-out effort to cut net carbon dioxide emissions 80 percent by 2020. Our goal is to prevent the atmospheric CO2 concentration from exceeding 400 ppm, thus limiting the future rise in temperature. This is an extraordinarily ambitious undertaking. It means, for example, phasing out all coal-fired power plants by 2020 while greatly reducing the use of oil.
Though the task is not simple, we can accomplish it using currently available technologies. The three components of the carbon-cutting effort are:
- halting deforestation while planting trees to sequester carbon,
- raising energy efficiency worldwide, and
- harnessing the earth's renewable sources of energy, particularly solar, wind, and geothermal energy.
Examples of the Plan B approach would be using the most energy-efficient technologies available for lighting, for heating and cooling buildings, and for transportation. For instance, it would mean a wholesale shift to plug-in hybrid cars, running them largely on wind-generated electricity.
Plan B includes a wholesale restructuring of the world energy economy with a wartime sense of urgency, much as the US restructured its industrial economy in a matter of months at the beginning of World War II. The stakes in World War II were high, but they are far higher today. What is at issue now is whether we can mobilize fast enough to save our global civilization.
|
About The Author
Lester R. Brown
is President of
Earth Policy Institute,
whose goal is to provide a plan for building a sustainable future and a roadmap of how to get from here to there. Brown has been described as "one of the world's most influential thinkers" by the Washington Post; The Telegraph of Calcutta called him "the guru of the environmental movement"; and the Library of Congress requested his papers for their archives.
|
|
|
|
Plan B 3.0
Mobilizing to Save Civilization
(by Lester Brown)
GP REVIEW: Modern economics rarely puts value on the products and services of earth's ecosystems—other than from a resource exploitation or development perspective. For instance, ignored are the benefits of forests, grasslands, wetlands, and coral reefs for purifying water, conserving soil, sequestering carbon, buffering coastal infrastructure against hurricanes, and providing spawning areas for fish. In Plan B 3.0, Lester Brown makes it very clear that we cannot continue to allow earth's essential systems to be "externalities" in the economic equation. To do so imperils civilization itself. Read full review of Plan B 3.0
|
|
|
Grinning Planet End Note
Thanks again to Lester Brown and the EPI team for their great work in Plan B 3.0 and for this article.
Know someone who might like this article about climate change and melting ice? Please forward it to them.
You can sign up for our free email list so you don't miss anything! Options:
Books:
- See books specifically related to Global Warming / Melting Ice
More articles and resources on....
|
|
|
