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Worldwatch Issue Alert #7
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>
> >>
> >>
> >>CLIMATE CHANGE HAS WORLD SKATING ON THIN ICE
> >>
> >>Lester R. Brown
> >>
> >> If any explorers had been hiking to the North Pole this summer, they
> would
> >>have had to swim the last few miles. The discovery of open water at the
> >>Pole by
> >>an ice-breaker cruise ship in mid August surprised many in the scientific
> >>community.
> >> This finding, combined with two recent studies, provides not only more
> >>evidence that the Earth's ice cover is melting, but that it is melting at an
> >>accelerating rate. A study by two Norwegian scientists projects that
> within 50
> >>years, the Arctic Ocean could be ice-free during the summer. The other, a
> >>study
> >>by a team of four U.S. scientists, reports that the vast Greenland ice
> >>sheet is
> >>melting.
> >> The projection that the Arctic Ocean will lose all its summer ice is not
> >>surprising, since an earlier study reported that the thickness of the ice
> >>sheet
> >>has been reduced by 42 percent over the last four decades. The area of
> the ice
> >>sheet has also shrunk by 6 percent. Together this thinning and shrinkage
> have
> >>reduced the Arctic Ocean ice mass by nearly half.
> >> Meanwhile, Greenland is gaining some ice in the higher altitudes, but
> >>it is
> >>losing much more at lower elevations, particularly along its southern and
> >>eastern coasts. The huge island of 2.2 million square kilometers (three
> times
> >>the size of Texas) is experiencing a net loss of some 51 billion cubic
> >>meters of
> >>water each year, an amount equal to the annual flow of the Nile River.
> >> The Antarctic is also losing ice. In contrast to the North Pole,
> which is
> >>covered by the Arctic Sea, the South Pole is covered by the Antarctic
> >>continent,
> >>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.
> >> 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 a year they lost another 3,000
> >>square kilometers. Delaware-sized icebergs that have broken off are
> >>threatening
> >>ships in the area. The scientists attribute the accelerated ice melting to a
> >>regional temperature rise of some 2.5 degrees Celsius (4.5 degrees
> Fahrenheit)
> >>since 1940.
> >> These are not the only examples of melting. My colleague, Lisa
> Mastny, who
> >>has reviewed some 30 studies on this topic, reports that ice is melting
> almost
> >>everywhere--and at an accelerating rate. (See Worldwatch News Brief,
> March 6,
> >>2000 http://www.worldwatch.org/alerts/000306.html ) 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 will disappear
> >>within 30
> >>years.
> >> Scientists studying the Quelccaya glacier in the Peruvian Andes report
> >>that
> >>its retreat has accelerated from 3 meters a year between roughly 1970 and
> 1990
> >>to 30 meters a year since 1990. In Europe's Alps, the shrinkage of the
> glacial
> >>area by 35-40 percent since 1850 is expected to continue. These ancient
> >>glaciers
> >>could largely disappear 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 meters
> >>between
> >>1992 and 1997, drew back by a further 20 meters in 1998 alone.
> >> This melting and shrinkage of snow/ice masses should not come as a total
> >>surprise. Swedish scientist Svente Arrhenius warned at the beginning of
> >>the last
> >>century that burning fossil fuels could raise atmospheric levels of carbon
> >>dioxide (CO2), creating a greenhouse effect. Atmospheric CO2 levels,
> estimated
> >>at 280 parts per million (ppm) before the Industrial Revolution, have
> climbed
> >>from 317 ppm in 1960 to 368 ppm in 1999--a gain of 16 percent in only four
> >>decades.
> >> As CO2 concentrations have risen, so too has Earth's temperature.
> Between
> >>1975 and 1999, the average temperature increased from 13.94 degrees
> Celsius to
> >>14.35 degrees, a gain of 0.41 degrees or 0.74 degrees Fahrenheit in 24
> years.
> >>The warmest 23 years since recordkeeping began in 1866 have all occurred
> since
> >>1975.
> >> Researchers are discovering that a modest rise in temperature of only
> >>1 or 2
> >>degrees Celsius in mountainous regions can dramatically increase the
> share of
> >>precipitation 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.
> >> These "reservoirs in the sky," where nature stores fresh water for
> use in
> >>the summer as the snow melts, are shrinking and some could disappear
> entirely.
> >>This will affect the water supply for cities and for irrigation in areas
> >>dependent on snowmelt to feed rivers.
> >> If the massive snow/ice mass in the Himalayas--which is the third
> >>largest in
> >>the world, after the Greenlandic and Antarctic 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. The melting in the Himalayas 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
> exacerbate
> >>the hydrological poverty already affecting so many in the region. (See Issue
> >>Alerts 1 and 4 www.worldwatch.org/alerts/indexia.html )
> >> As the ice on land melts and flows to the sea, sea level rises. Over the
> >>last century, sea level rose by 20-30 centimeters (8-12 inches). During this
> >>century, the existing climate models indicate it could rise by as much as 1
> >>meter. If the Greenland ice sheet, which is up to 3.2 kilometers thick in
> >>places, were to melt entirely, sea level would rise by 7 meters (23 feet).
> >> Even a much more modest rise would affect the low-lying river
> >>floodplains of
> >>Asia, where much of the region's rice is produced. According to a World Bank
> >>analysis, a 1-meter rise in sea level would cost low-lying Bangladesh
> half its
> >>riceland. Numerous low-lying island countries would have to be evacuated.
> The
> >>residents of densely populated river valleys of Asia would be forced
> >>inland into
> >>already crowded interiors. Rising sea level could create climate refugees
> >>by the
> >>million in countries such as China, India, Bangladesh, Indonesia, Viet
> >>Nam, and
> >>the Philippines.
> >> Even more disturbing, ice melting itself can accelerate temperature
> >>rise. As
> >>snow/ice masses shrink, less sunlight is reflected back into space. With
> more
> >>sunlight absorbed by less reflective surfaces, temperature rises even
> >>faster and
> >>melting accelerates.
> >> We don't have to sit idly by as this scenario unfolds. There may
> still be
> >>time to stabilize atmospheric CO2 levels before continuing carbon emissions
> >>cause climate change to spiral out of control. We have more than enough
> wind,
> >>solar, and geothermal energy that can be economically harnessed to power the
> >>world economy. If we were to incorporate the cost of climate disruption
> in the
> >>price of fossil fuels in the form of a carbon tax, investment would quickly
> >>shift from fossil fuels to these climate-benign energy sources.
> >> The leading automobile companies are all working on fuel cell engines.
> >>Daimler Chrysler plans to start marketing such an automobile in 2003. The
> fuel
> >>of choice for these engines is hydrogen. Even leaders within the oil
> industry
> >>recognize that we will eventually shift from a carbon-based energy economy
> >>to a
> >>hydrogen-based one. The question is whether we can make that shift before
> >>Earth's climate system is irrevocably altered.
> >>
> >>- end -
> >>
> >>FOR DATA, GRAPHS, AND ADDITIONAL INFORMATION
> >>WWW.WORLDWATCH.ORG/ALERTS/INDEXIA.HTML
> >>If you know someone who might like to receive the Issue Alerts regularly,
> >>please
> >>contact Reah Janise Kauffman rjkauffman@worldwatch.org .
> >>
> >>COPYRIGHT: 2000 Worldwatch Institute
> >>CONTACT: Reah Janise Kauffman
> >>PHONE: (202) 452-1992 x 514
> >>FAX: (202) 296-7365
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