"Urban transport systems based on a combination of rail lines, bus lines, bicycle pathways, and pedestrian walkways offer the best of all possible worlds in providing mobility, low-cost transportation, and a healthy urban environment." –Lester R. Brown, Plan B 4.0: Mobilizing to Save Civilization.
Chapter 2. Signs of Stress: Climate & Water: The Ice is Melting
Ice melting is one of the most visible manifestation of global warming. Sometimes the evidence that mountain glaciers are melting takes novel forms. In late 1991, hikers in the southwestern Alps on the Austrian-Italian border discovered an intact male human body protruding from a glacier. Apparently trapped in a storm more than 5,000 years ago and quickly covered with snow and ice, his body was remarkably well preserved. In 1999, another body was found in a melting glacier in the Yukon Territory of western Canada. As I noted at the time, our ancestors are emerging from the ice with a message for us: the earth is getting warmer.13
In the Arctic Ocean, sea ice is melting fast. As recently as 1960, the Arctic sea ice was nearly 2 meters thick. In 2001, it averaged scarcely a meter. Over the last four decades, the ice sheet has thinned by 42 percent and it has shrunk in area by 6 percent. Together, this thinning and shrinkage have reduced the Arctic Ocean ice mass by nearly half. This rapid melting is expected to continue. A recent study by two Norwegian scientists projects that within 50 years the Arctic Ocean could be ice-free during the summer.14
In 2000, four U.S. scientists published an article in Science reporting that the vast Greenland ice sheet is starting to melt. Lying largely within the Arctic Circle, Greenland is gaining some ice in higher elevations on its northern reaches, but it is losing much more at lower elevations, particularly along its southern and eastern coasts. This huge island of 2.2 million square kilometers (three times the size of Texas) is experiencing a net loss of 51 billion cubic meters of water each year, an amount approaching two thirds of the annual flow of the Nile River as it enters Egypt.15
The Antarctic peninsula is also losing ice. In contrast to the North Pole, which is covered by the Arctic Sea, the South Pole is covered by the continent of Antarctica, a land mass roughly the size of the United States. Its continent-sized ice sheet, which is on average 2.3 kilometers (1.5 miles) thick, is relatively stable. But the ice shelves, the portions of the ice sheet that extend into the surrounding seas, are fast disappearing.16
A team of U.S. and British scientists reported in 1999 that the ice shelves on either side of the Antarctic peninsula are in full retreat. From roughly mid-century through 1997, these areas lost 7,000 square kilometers as the ice sheet disintegrated. But then within scarcely one year they lost another 3,000 square kilometers. Delaware-sized icebergs that have broken off are a threat to ships in the area. The scientists attribute the accelerated ice melting to a regional temperature rise of 2.5 degrees Celsius (4.5 degrees Fahrenheit) since 1940.17
These are not the only examples of melting. Lisa Mastny of Worldwatch Institute, who reviewed some 30 studies on this topic, reports that mountain glaciers are melting worldwide-and at an accelerating rate. (See Table 2-1.) The snow/ice mass is shrinking in the world's major mountain ranges: the Rocky Mountains, the Andes, the Alps, and the Himalayas. In Glacier National Park in Montana, the number of glaciers has dwindled from 150 in 1850 to fewer than 50 today. The U.S. Geological Survey projects that the remaining glaciers could disappear within 30 years.18
In Europe's Alps, the shrinkage of the glacial volume by more than half since 1850 is expected to continue, with these ancient glaciers largely disappearing over the next half-century. Shrinkage of ice masses in the Himalayas has accelerated alarmingly. In eastern India, the Dokriani Bamak glacier, which retreated by 16.5 meters between 1992 and 1997, drew back by a further 20 meters in 1998 alone.19
A research report by Lonnie Thompson of Ohio State University indicates that the ice cap on Kilimanjaro could disappear within 15 years. This upset Tanzania's Minister of Tourism, Zokia Meghji, who told parliament that the projected melting was exaggerated, as he tried to allay fears about the effects on the country's lucrative tourism industry. In response, Thompson pointed out that his report was simply based on an extrapolation of the recent historical trend.20
Researchers are discovering that a modest rise in temperature of 1-2 degrees Celsius in mountainous regions can dramatically alter the precipitation mix, increasing the share falling as rain while decreasing the share coming down as snow. The result is more flooding during the rainy season, a shrinking snow/ice mass, and less snowmelt to feed rivers during the dry season.21
These "reservoirs in the sky," where nature stores fresh water for use in the summer as the snow melts, have been there ever since irrigation began, supplying farmers with water for several thousand years. Now suddenly, in a matter of years, they are shrinking and some could disappear entirely, sharply reducing the water supply for irrigation and for cities.
If the massive snow/ice sheet in the Himalayas—which is the third largest in the world, after the Antarctic and Greenland ice sheets—continues to melt, it will affect the water supply of much of Asia. All of the region's major rivers—the Indus, Ganges, Mekong, Yangtze, and Yellow—originate in the Himalayas. Melting in this area could alter the hydrology of several Asian countries, including Pakistan, India, Bangladesh, Thailand, Viet Nam, and China. Less snowmelt in the summer dry season to feed rivers could worsen the hydrological poverty already afflicting so many in the region.22
We don't have to sit idly by as this scenario unfolds. There may still be time to stabilize atmospheric CO2 levels before carbon emissions lead to unmanageable climate change. There is an abundance of wind, solar, and geothermal energy to harness for running the world economy. (See Chapter 5.) If we were to cut income taxes and offset this by incorporating a carbon tax that reflected the cost of climate disruption in the price of fossil fuels, investment would quickly shift from fossil fuels to these climate-stabilizing energy sources.
|Table 2-1. Selected Examples of Ice Melt Around the World|
|Source: Updated from Lisa Mastny, "Melting of Earth's Ice Cover Reaches New High," Worldwatch News Brief (Washington, DC: Worldwatch Institute: 6 March 2000).|
13. John Noble Wilford, "Move Over, Iceman! New Star From the Andes," New York Times, 25 October 1995; James Brooke, "Remains of Ancient Man Discovered in Melting Canadian Glacier," New York Times, 25 August 1999.
14. Lisa Mastny, "Melting of Earth's Ice Cover Reaches New High," Worldwatch News Brief (Washington, DC: 6 March 2000); Wilford, op. cit. note 1; 50-year projection in Lars H. Smedsrud and Tore Furevik, "Towards an Ice-Free Arctic?" Cicerone, no. 2, 2000.
15. W. Krabill et al., "Greenland Ice Sheet: High Elevation Balance and Peripheral Thinning," Science, 21 July 2000, p. 428; usable flow of the Nile River is 74 billion cubic meters, according to Sandra Postel, Pillar of Sand (New York: W.W. Norton & Company, 1999), pp. 71, 146.
16. "Melting of Antarctic Ice Shelves Accelerates," Environmental News Network, 9 April 1999.
18. Mastny, op. cit. note 14.
20. Lonnie G. Thompson, "Disappearing Glaciers Evidence of a Rapidly Changing Earth," American Association for the Advancement of Science annual meeting proceedings, San Francisco, CA February 2001; response by Zakia Meghji in "Newswire," New Scientist, 26 May 2001.
21. Christopher B. Field et al., Confronting Climate Change in California: Ecological Impacts on the Golden State (Cambridge, MA: Union of Concerned Scientists, 1999), pp. 2-3, 10.
22. Robert Marquand, "Glaciers in the Himalayas Melting at Rapid Rate," Christian Science Monitor, 5 November 1999.
Copyright © 2001 Earth Policy Institute