Global Warming in Antarctica

1.Scientists are also studying the Antarctic ice and ice flow in an attempt to determine whether the greenhouse effect, a global warming trend caused by rising levels of atmospheric carbon dioxide, is changing conditions in the Antarctic; examples of such are the thickness of the ice cap and the movement of Antarctic ocean currents, which help cool the Earth. Recent studies indicate that the temperature of Antarctica has increased by 2.5 C degrees (4.5 F degrees) over the last 50 years—a more rapid increase than almost anywhere else on Earth. At the same time, a study (published 2002) of several ice rivers flowing to the coast along the Ross Ice Shelf concluded that they were slowing and thickening. Ice rivers in other parts of western Antarctica were speeding up and sending more ice toward the sea. Thus the contribution of Antarctica to rising world sea levels remains unclear.
2.Global surface temperatures have risen chiefly because of a process called the greenhouse effect. In the greenhouse effect, certain gases in the atmosphere trap heat from the sun, acting much like the glass roof and walls of a greenhouse (see Greenhouse effect). The heat-trapping gases are called greenhouse gases. They include methane (CH₄), nitrous oxide (N₂O), ozone (O₃), and a number of industrial gases. But the gas that has produced the most warming is carbon dioxide (CO₂).
3.The average temperature of Earth's surface has increased by about 1.4 Fahrenheit degrees (0.76 Celsius degree) since the mid-1800's. Most of the temperature rise happened from the mid-1900's to the 2000's. Scientists have shown that it is probable that human-caused increases in greenhouse gas concentrations are responsible for most of the recent warming. CO2 ranks as the gas that has produced the most warming. Researchers have estimated that Earth's average surface temperature will rise another 2.0 to 11.5 Fahrenheit degrees (1.1 to 6.4 Celsius degrees) by 2100.