Antarctica
Antarctica is a continent of contradictions: volcanoes erupting from a frozen landscape; miles of snow and ice, yet hardly any snow falls each year; an arid land surrounded by three oceans.
A layer of ice up to two miles thick covers a continent as big as the United States and Mexico combined. Antarctic ice contains 70% of the world's fresh water (90% of the world's ice). If it were divided up, every person on Earth could have a chunk of ice larger than the Great Pyramid. Although 98% of Antarctica is ice, there is land underneath the ice cover, unlike the Arctic where the ice floats on top of the ocean.
The average temperature on the Antarctic continent is -49oC. The lowest temperature ever recorded anywhere on Earth was measured here at -128.60F (-89oC.). Water temperature averages a comparatively balmy 33oF. Salt water temperature will drop to about 28oF before it freezes. Because of the frigid air temperatures, rain rarely falls here. It rarely snows either; the South Pole gets less than 6 inches of snow a year. For six months every year, the sun shines 24 hours a day at the South Pole. But don't expect it to warm you up much. Winds reach up to 200 mph along the coast. During the dark six months of the year, the Antarctic winter (our summer), the South Pole station has a population of 28 people who can't leave. For seven months, from early February until a plane flies in mid-winter with supplies, their only link to the outside world is via the Internet, phone, and radio.
Much of the information that the outside world learns about Antarctica is gathered from several hundred miles up space. Satellites track changes in Antarctic water temperature, sea ice cover, and the shrinking and expansion of the ozone layer above the continent. These observations relate directly to biological productivity and the Antarctic food chain. Changes in sea ice cover, for example, apparently affect the population of krill that feed hales and penguins and have been tied to the survival ratio of penguin chicks over a breeding season.
"What time is it?" is a tricky question in a place where all time zones converge. So everyone in Antarctica officially goes by New Zealand time.
Plant and animal fossils and coal beds indicate it was once warm here. Antarctica, all alone at the bottom of the world, was once part of a larger land mass near the equator and gradually moved southward. What is now the Antarctic was once attached to India, Africa, Australia, and South America. This land mass, Gondwanaland, began breaking apart about 180 million years ago. Plate tectonics, the theory that the Earth's crust is composed of several moving plates, accounts for Antarctica's journey south.
Volcanologists eagerly crowd the cone of Antarctica's active volcano, 12, 447 foot-high Mt. Erebus, to monitor its continual small eruptions. A permanent lava lake in the center serves as a "window to the Earth's mantle."
One could say that most of Antarctica is high and dry. Its average elevation is three times that of other countries. The South Pole itself sits on a plateau 10,000 feet above sea level. Antarctica's highest peak is 16,066 feet, just over three miles high.
Antarctica has the distinction of being the most peaceful place on Earth. No wars have ever been fought on Antarctica. No sovereign country rules it. Tourists and scientists don't need a passport, a visa, or anyone's permission to visit. This "Zone of Peace" is dedicated to science, with a multinational treaty that prohibits mining or acting on land claims.
Sea Level Over the past century, sea level is estimated to have risen about 4 to 8 inches (10-20 centimeters) worldwide. If global warming causes sea level to rise, scientists claim it will be from two main factors: the partial melting of the ice caps, snow fields, and small glaciers, and the thermal expansion of sea water; as it warms, it takes up more volume. Other more localized factors, besides atmospheric warming, may influence sea level rise including: human-caused subsidence by pumping out groundwater, oil, natural gas, or erosion by hurricanes of natural sand buffers. Predictions of future sea level rise are hard to make, but some scientists estimate that melting ice and warming ocean water could raise sea level by as much as one meter by 2100.
One of the least understood areas is the West Antarctic ice sheet and its potential for breaking up into giant icebergs. In one scenario, if global warming results in even a small rise in sea level, warmer water could flow under the West Antarctic ice sheet and break off ice chunks the size of New England. These ice chunks, which now sit on land, could raise sea level an estimated 18 feet worldwide, flooding coastal cities like Portland, Maine and Boston, Massachusetts. Most scientists now think this scenario is unlikely to occur, and if it did, it would take centuries to happen. Some scientists say that increased moisture from global warming could turn to snow in the Antarctic. This could actually contribute to a fall in sea level as the Antarctic locks up the moisture as ice. Most scientists caution that it is very hard to predict what will actually happen.
Why won't the floating ice caps melting in the North Pole/Arctic Ocean affect sea level? (Because this floating ice is already displacing its own volume in water.) Only the ice that breaks off or melts from land, i.e. the Greenland ice sheet, Antarctic ice sheet, and mountain glaciers can raise sea level.
A layer of ice up to two miles thick covers a continent as big as the United States and Mexico combined. Antarctic ice contains 70% of the world's fresh water (90% of the world's ice). If it were divided up, every person on Earth could have a chunk of ice larger than the Great Pyramid. Although 98% of Antarctica is ice, there is land underneath the ice cover, unlike the Arctic where the ice floats on top of the ocean.
The average temperature on the Antarctic continent is -49oC. The lowest temperature ever recorded anywhere on Earth was measured here at -128.60F (-89oC.). Water temperature averages a comparatively balmy 33oF. Salt water temperature will drop to about 28oF before it freezes. Because of the frigid air temperatures, rain rarely falls here. It rarely snows either; the South Pole gets less than 6 inches of snow a year. For six months every year, the sun shines 24 hours a day at the South Pole. But don't expect it to warm you up much. Winds reach up to 200 mph along the coast. During the dark six months of the year, the Antarctic winter (our summer), the South Pole station has a population of 28 people who can't leave. For seven months, from early February until a plane flies in mid-winter with supplies, their only link to the outside world is via the Internet, phone, and radio.
Much of the information that the outside world learns about Antarctica is gathered from several hundred miles up space. Satellites track changes in Antarctic water temperature, sea ice cover, and the shrinking and expansion of the ozone layer above the continent. These observations relate directly to biological productivity and the Antarctic food chain. Changes in sea ice cover, for example, apparently affect the population of krill that feed hales and penguins and have been tied to the survival ratio of penguin chicks over a breeding season.
"What time is it?" is a tricky question in a place where all time zones converge. So everyone in Antarctica officially goes by New Zealand time.
Plant and animal fossils and coal beds indicate it was once warm here. Antarctica, all alone at the bottom of the world, was once part of a larger land mass near the equator and gradually moved southward. What is now the Antarctic was once attached to India, Africa, Australia, and South America. This land mass, Gondwanaland, began breaking apart about 180 million years ago. Plate tectonics, the theory that the Earth's crust is composed of several moving plates, accounts for Antarctica's journey south.
Volcanologists eagerly crowd the cone of Antarctica's active volcano, 12, 447 foot-high Mt. Erebus, to monitor its continual small eruptions. A permanent lava lake in the center serves as a "window to the Earth's mantle."
One could say that most of Antarctica is high and dry. Its average elevation is three times that of other countries. The South Pole itself sits on a plateau 10,000 feet above sea level. Antarctica's highest peak is 16,066 feet, just over three miles high.
Antarctica has the distinction of being the most peaceful place on Earth. No wars have ever been fought on Antarctica. No sovereign country rules it. Tourists and scientists don't need a passport, a visa, or anyone's permission to visit. This "Zone of Peace" is dedicated to science, with a multinational treaty that prohibits mining or acting on land claims.
Sea Level Over the past century, sea level is estimated to have risen about 4 to 8 inches (10-20 centimeters) worldwide. If global warming causes sea level to rise, scientists claim it will be from two main factors: the partial melting of the ice caps, snow fields, and small glaciers, and the thermal expansion of sea water; as it warms, it takes up more volume. Other more localized factors, besides atmospheric warming, may influence sea level rise including: human-caused subsidence by pumping out groundwater, oil, natural gas, or erosion by hurricanes of natural sand buffers. Predictions of future sea level rise are hard to make, but some scientists estimate that melting ice and warming ocean water could raise sea level by as much as one meter by 2100.
One of the least understood areas is the West Antarctic ice sheet and its potential for breaking up into giant icebergs. In one scenario, if global warming results in even a small rise in sea level, warmer water could flow under the West Antarctic ice sheet and break off ice chunks the size of New England. These ice chunks, which now sit on land, could raise sea level an estimated 18 feet worldwide, flooding coastal cities like Portland, Maine and Boston, Massachusetts. Most scientists now think this scenario is unlikely to occur, and if it did, it would take centuries to happen. Some scientists say that increased moisture from global warming could turn to snow in the Antarctic. This could actually contribute to a fall in sea level as the Antarctic locks up the moisture as ice. Most scientists caution that it is very hard to predict what will actually happen.
Why won't the floating ice caps melting in the North Pole/Arctic Ocean affect sea level? (Because this floating ice is already displacing its own volume in water.) Only the ice that breaks off or melts from land, i.e. the Greenland ice sheet, Antarctic ice sheet, and mountain glaciers can raise sea level.
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