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bushman
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Disappearing mountain glaciers mean less water for essential river systems....
Meanwhile some of us worry about our investments....
By 2020, the snows of Kilimanjaro may exist only in old photographs. The
glaciers in Montana's Glacier National Park could disappear by 2030. And by
mid-century, the Arctic Sea may be completely ice-free during summertime. As
the earth's temperature has risen in recent decades, the earth's ice cover
has begun to melt. And that melting is accelerating.
In both 2002 and 2003, the Northern Hemisphere registered record-low sea ice
cover. New satellite data show the Arctic region warming more during the
1990s than during the 1980s, with Arctic Sea ice now melting by up to 15
percent per decade. The long-sought Northwest Passage, a dream of early
explorers, could become our nightmare. The loss of Arctic Sea ice could
alter ocean circulation patterns and trigger changes in global climate
patterns.
On the opposite end of the globe, Southern Ocean sea ice floating near
Antarctica has shrunk by some 20 percent since 1950. This unprecedented
melting of sea ice corroborates records showing that the regional air
temperature has increased by 2.5 degrees Celsius (4.5 degrees Fahrenheit)
since 1950.
Antarctic ice shelves that existed for thousands of years are crumbling. One
of the world's largest icebergs, named B-15, that measured near 10,000
square kilometers (4,000 square miles) or half the size of New Jersey,
calved off the Ross Ice Shelf in March 2000. In May 2002, the shelf lost
another section measuring 31 kilometers (19 miles) wide and 200 kilometers
(124 miles) long.
Elsewhere on Antarctica, the Larsen Ice Shelf has largely disintegrated
within the last decade, shrinking to 40 percent of its previously stable
size. Following the break-off of the Larsen A section in 1995 and the
collapse of Larsen B in early 2002, melting of the nearby land-based
glaciers that the ice shelves once supported has more than doubled.
Unlike the melting of sea ice or the floating ice shelves along coasts, the
melting of ice on land raises sea level. Recent studies showing the
worldwide acceleration of glacier melting indicate that the
Intergovernmental Panel on Climate Change's estimate for sea level rise this
century -- ranging from 0.1 meters to 0.9 meters -- will need to be revised
upwards. (See table of selected examples of ice melt from around the world.)
On Greenland, an ice-covered island three times the size of Texas,
once-stable glaciers are now melting at a quickening rate. The Jakobshavn
Glacier on the island's southwest coast, which is one of the major drainage
outlets from the interior ice sheet, is now thinning four times faster than
during most of the twentieth century. Each year Greenland loses some 51
cubic kilometers of ice, enough to annually raise sea level 0.13
millimeters. Were Greenland's entire ice sheet to melt, global sea level
could rise by a startling 7 meters (23 feet), inundating most of the world's
coastal cities.
The Himalayas contain the world's third largest ice mass after Antarctica
and Greenland. Most Himalayan glaciers have been thinning and retreating
over the past 30 years, with losses accelerating to alarming levels in the
past decade. On Mount Everest, the glacier that ended at the historic base
camp of Edmund Hillary and Tenzing Norgay, the first humans to reach the
summit, has retreated 5 kilometers (3 miles) since their 1953 ascent.
Glaciers in Bhutan are retreating at an average rate of 30 -- 40 meters a
year. A similar situation is found in Nepal.
As the glaciers melt they are rapidly filling glacial lakes, creating a
flood risk. An international team of scientists has warned that with current
melt rates, at least 44 glacial lakes in the Himalayas could burst their
banks in as little as five years.
Glaciers themselves store vast quantities of water. More than half of the
world's population relies on water that originates in mountains, coming from
rainfall runoff or ice melt. In some areas glaciers help sustain a constant
water supply; in others, meltwater from glaciers is a primary water source
during the dry season. In the short term, accelerated melting means that
more water feeds rivers. Yet as glaciers disappear, dry season river flow
declines.
The Himalayan glaciers feed the seven major rivers of Asia -- the Ganges,
Indus, Brahmaputra, Salween, Mekong, Yangtze, and Huang He (Yellow) -- and
thus contribute to the year-round water supply of a vast population. In
India alone, some 500 million people, including those in New Delhi and
Calcutta, depend on glacier meltwater that feeds into the Ganges River
system. Glaciers in Central Asia's Tien Shan Mountains have shrunk by nearly
30 percent between 1955 and 1990. In arid western China, shrinking glaciers
account for at least 10 percent of freshwater supplies.
The largest aggregation of tropical glaciers is in the northern Andes. The
retreat of the Qori Kalis Glacier on the west side of the Quelccaya Ice Cap
that stretches across Peru has accelerated to 155 meters a year between 1998
and 2000—three times faster than during the previous three-year period. The
entire ice cap could vanish over the next two decades.
The Antizana Glacier, which provides Quito, Ecuador, with almost half its
water, has retreated more than 90 meters over the last eight years. The
Chacaltaya Glacier near La Paz, Bolivia, melted to 7 percent of its 1940s
volume by 1998. It could disappear entirely by the end of this decade,
depriving the 1.5 million people in La Paz and the nearby city of Alto of an
important source of water and power.
Africa's glaciers are also disappearing. Across the continent, mountain
glaciers have shrunk to one third their size over the twentieth century. On
Kenya's Kilimanjaro, ice cover has shrunk by more than 33 percent since
1989. By 2020 it could be completely gone.
In Western Europe, glacial area has shrunk by up to 40 percent and glacial
volume by more than half since 1850. If temperatures continue to rise at
recent rates, major sections of glaciers covering the Alps and the French
and Spanish Pyrenees could be gone in the next few decades. During the
record-high temperature summer of 2003, some Swiss glaciers retreated by an
unprecedented 150 meters. The United Nations Environment Programme is
warning that for this region long associated with ice and snow, warming
temperatures signify the demise of a popular ski industry, not to mention a
cultural identity.
Boundaries around Banff, Yoho, and Jasper National Parks in the Canadian
Rockies cannot stop the melting of the glaciers there. Glacier National Park
in Montana has lost over two thirds of its glaciers since 1850. If
temperatures continue to rise, it may lose the remainder by 2030.
In just the past 30 years, the average temperature in Alaska climbed more
than 3 degrees Celsius (5 degrees Fahrenheit) -- easily four times the
global increase. Glaciers in all of Alaska's 11 glaciated mountain ranges
are shrinking. Since the mid-1990s, Alaskan glaciers have been thinning by
1.8 meters a year, more than three times as fast as during the preceding 40
years.
The global average temperature has climbed by 0.6 degrees Celsius (1 degree
Fahrenheit) in the past 25 years. Over this time period, melting of sea ice
and mountain glaciers has increased dramatically. During this century,
global temperature may rise between 1.4 and 5.8 degrees Celsius, and melting
will accelerate further. Just how much will depend in part on the energy
policy choices made today.
http://www.21stcenturyradio.com/articles/04/0128271.html
Meanwhile some of us worry about our investments....
By 2020, the snows of Kilimanjaro may exist only in old photographs. The
glaciers in Montana's Glacier National Park could disappear by 2030. And by
mid-century, the Arctic Sea may be completely ice-free during summertime. As
the earth's temperature has risen in recent decades, the earth's ice cover
has begun to melt. And that melting is accelerating.
In both 2002 and 2003, the Northern Hemisphere registered record-low sea ice
cover. New satellite data show the Arctic region warming more during the
1990s than during the 1980s, with Arctic Sea ice now melting by up to 15
percent per decade. The long-sought Northwest Passage, a dream of early
explorers, could become our nightmare. The loss of Arctic Sea ice could
alter ocean circulation patterns and trigger changes in global climate
patterns.
On the opposite end of the globe, Southern Ocean sea ice floating near
Antarctica has shrunk by some 20 percent since 1950. This unprecedented
melting of sea ice corroborates records showing that the regional air
temperature has increased by 2.5 degrees Celsius (4.5 degrees Fahrenheit)
since 1950.
Antarctic ice shelves that existed for thousands of years are crumbling. One
of the world's largest icebergs, named B-15, that measured near 10,000
square kilometers (4,000 square miles) or half the size of New Jersey,
calved off the Ross Ice Shelf in March 2000. In May 2002, the shelf lost
another section measuring 31 kilometers (19 miles) wide and 200 kilometers
(124 miles) long.
Elsewhere on Antarctica, the Larsen Ice Shelf has largely disintegrated
within the last decade, shrinking to 40 percent of its previously stable
size. Following the break-off of the Larsen A section in 1995 and the
collapse of Larsen B in early 2002, melting of the nearby land-based
glaciers that the ice shelves once supported has more than doubled.
Unlike the melting of sea ice or the floating ice shelves along coasts, the
melting of ice on land raises sea level. Recent studies showing the
worldwide acceleration of glacier melting indicate that the
Intergovernmental Panel on Climate Change's estimate for sea level rise this
century -- ranging from 0.1 meters to 0.9 meters -- will need to be revised
upwards. (See table of selected examples of ice melt from around the world.)
On Greenland, an ice-covered island three times the size of Texas,
once-stable glaciers are now melting at a quickening rate. The Jakobshavn
Glacier on the island's southwest coast, which is one of the major drainage
outlets from the interior ice sheet, is now thinning four times faster than
during most of the twentieth century. Each year Greenland loses some 51
cubic kilometers of ice, enough to annually raise sea level 0.13
millimeters. Were Greenland's entire ice sheet to melt, global sea level
could rise by a startling 7 meters (23 feet), inundating most of the world's
coastal cities.
The Himalayas contain the world's third largest ice mass after Antarctica
and Greenland. Most Himalayan glaciers have been thinning and retreating
over the past 30 years, with losses accelerating to alarming levels in the
past decade. On Mount Everest, the glacier that ended at the historic base
camp of Edmund Hillary and Tenzing Norgay, the first humans to reach the
summit, has retreated 5 kilometers (3 miles) since their 1953 ascent.
Glaciers in Bhutan are retreating at an average rate of 30 -- 40 meters a
year. A similar situation is found in Nepal.
As the glaciers melt they are rapidly filling glacial lakes, creating a
flood risk. An international team of scientists has warned that with current
melt rates, at least 44 glacial lakes in the Himalayas could burst their
banks in as little as five years.
Glaciers themselves store vast quantities of water. More than half of the
world's population relies on water that originates in mountains, coming from
rainfall runoff or ice melt. In some areas glaciers help sustain a constant
water supply; in others, meltwater from glaciers is a primary water source
during the dry season. In the short term, accelerated melting means that
more water feeds rivers. Yet as glaciers disappear, dry season river flow
declines.
The Himalayan glaciers feed the seven major rivers of Asia -- the Ganges,
Indus, Brahmaputra, Salween, Mekong, Yangtze, and Huang He (Yellow) -- and
thus contribute to the year-round water supply of a vast population. In
India alone, some 500 million people, including those in New Delhi and
Calcutta, depend on glacier meltwater that feeds into the Ganges River
system. Glaciers in Central Asia's Tien Shan Mountains have shrunk by nearly
30 percent between 1955 and 1990. In arid western China, shrinking glaciers
account for at least 10 percent of freshwater supplies.
The largest aggregation of tropical glaciers is in the northern Andes. The
retreat of the Qori Kalis Glacier on the west side of the Quelccaya Ice Cap
that stretches across Peru has accelerated to 155 meters a year between 1998
and 2000—three times faster than during the previous three-year period. The
entire ice cap could vanish over the next two decades.
The Antizana Glacier, which provides Quito, Ecuador, with almost half its
water, has retreated more than 90 meters over the last eight years. The
Chacaltaya Glacier near La Paz, Bolivia, melted to 7 percent of its 1940s
volume by 1998. It could disappear entirely by the end of this decade,
depriving the 1.5 million people in La Paz and the nearby city of Alto of an
important source of water and power.
Africa's glaciers are also disappearing. Across the continent, mountain
glaciers have shrunk to one third their size over the twentieth century. On
Kenya's Kilimanjaro, ice cover has shrunk by more than 33 percent since
1989. By 2020 it could be completely gone.
In Western Europe, glacial area has shrunk by up to 40 percent and glacial
volume by more than half since 1850. If temperatures continue to rise at
recent rates, major sections of glaciers covering the Alps and the French
and Spanish Pyrenees could be gone in the next few decades. During the
record-high temperature summer of 2003, some Swiss glaciers retreated by an
unprecedented 150 meters. The United Nations Environment Programme is
warning that for this region long associated with ice and snow, warming
temperatures signify the demise of a popular ski industry, not to mention a
cultural identity.
Boundaries around Banff, Yoho, and Jasper National Parks in the Canadian
Rockies cannot stop the melting of the glaciers there. Glacier National Park
in Montana has lost over two thirds of its glaciers since 1850. If
temperatures continue to rise, it may lose the remainder by 2030.
In just the past 30 years, the average temperature in Alaska climbed more
than 3 degrees Celsius (5 degrees Fahrenheit) -- easily four times the
global increase. Glaciers in all of Alaska's 11 glaciated mountain ranges
are shrinking. Since the mid-1990s, Alaskan glaciers have been thinning by
1.8 meters a year, more than three times as fast as during the preceding 40
years.
The global average temperature has climbed by 0.6 degrees Celsius (1 degree
Fahrenheit) in the past 25 years. Over this time period, melting of sea ice
and mountain glaciers has increased dramatically. During this century,
global temperature may rise between 1.4 and 5.8 degrees Celsius, and melting
will accelerate further. Just how much will depend in part on the energy
policy choices made today.
http://www.21stcenturyradio.com/articles/04/0128271.html
