ANTARTICA: Global Warming Effects 4*2*

Project Work

Antartica: Global Warming Effects


Students: Eduardo Rojas
Christian G. Palavecino

Teacher: Stella Maris Goldenzweig

Course. 4to 2da


Year: 2008



ANTARTICA: Global Warming Effects

Antarctica gives mixed signals on warming. Is the zone more sensitive to climatic change than other regions and scientists are looking to it to predict the future climate of the globe? No one can seem to agree about whether or not Antarctica is warming or cooling; various different studies claim one, the other, both, or that measuring melting as a sign of global temperature change is not applicable in Antarctica because cycles of melting and refreezing are part of normal glaciations. However, the majority of researchers seem to agree that the amount of ice that has been melting lately in Antarctica is cause for concern. Yet it seems a bit strange that they should preach about mankind's destruction of the environment when, in the name of research, Antarctica has been "conquered", colonized with an airport, roads, and power plants to house about 1200 people in the McMurdo station alone.

While the Arctic and the Antarctic experience similar greenhouse gas levels and solar radiation, each region responds in a dramatically different way, especially in temperature and loss of sea ice.
Scientists have concluded, based on new research since the 2007 Intergovernmental Panel on Climate Change Report, that a combination of factors is responsible for the recent dramatic sea ice loss in the Arctic as well as masking some of the effects in the Antarctic.

But there are inconsistent reports because the total surface area of Antarctica doubles in winter with the addition of sea ice. You can't expect an area three times the size of Australia to behave the same way throughout. This is a tricky region and is more likely to do its own thing as the rest of the planet warms.

Temperature
For most of the Antarctic, temperatures were not unusual, except on the Antarctic Peninsula, a finger of land and ice about 1,000 miles south of the tip of South America, which had the largest increase in temperatures of any location in the Southern Hemisphere.


Temperatures warmed by three degrees Fahrenheit. Warming temperatures and exposure to ocean waves were cited by the National Snow and Ice Data Center as the cause of the collapse of a 160-square-mile segment of the Wilkins Ice Shelf on the peninsula, which began collapsing in late February.

The Antarctic Peninsula is particularly sensitive to small rises in the annual average temperature, this has increased about 2.5C in the region in the last 50 years, and this is 2 or 3 times faster than the average in the rest of the world. This makes it an excellent study area.
The temperature of the rest of Antarctica - the other 96% - shows no current indications of rising.

If the whole of Antarctica were divided into grips about 60 to 70 percent of the squares would reveal a cooling trend, while warming would be seen in the other 30 to 40 percent of the overall area. So there's a slight net cooling for the entire continent.

Sea Ice
Story is clearer.
Gillett, a climate dynamics scientist, said, “In the Antarctic, the changes in winds and temperatures are consistent with how we would expect them to respond to increased greenhouse gases and depletion of stratospheric ozone.”
The depletion of ozone has strengthened the atmospheric circulation, called the Southern Annual Mode, or SAM. As the ozone hole recovers, the winds that currently whiz around Antarctica and block air masses from crossing into the continent’s interior would weaken, and Antarctica would no longer be so isolated from global warming patterns.

However, data on temperatures in Antarctica only really go back about 50 years, anything beyond that is surmised from ice cores or other sources and as a result we don't really know how the temperatures vary over even the medium term in Antarctica.


Biological Effects of Global Warming

Antarctica's only two flowering plant species that grow only on the Peninsula have spread considerably in the last few decades in both geographic distribution and also abundance in the areas where they are found. In some areas they are becoming the dominant species.



Penguins have also been suffering a steady decline in parts of the Antarctic
Peninsula region for the last 20 years. They are reducing in number and abandoning certain nesting sites

Studies have shown that stocks of krill in Antarctica have declined dramatically in recent years. The reason for this is likely to be a fall in the amount of sea ice in the winter months. There are commercial implications as well as scientific ones. The Southern Ocean is a valuable fisheries resource; many of the species caught feed on krill. Thousands of tourists are also attracted to Antarctica to enjoy the spectacular wildlife, most of which feed on krill. This decline in krill will also make it more difficult for the great baleen whales to return to pre-exploitation levels following their decimation in numbers.



The Future
The British Antarctic Survey, which has undertaken the majority of Britain's scientific research in the area, has the following positions: [6]
Ice makes polar climate sensitive by introducting a strong positive feedback loop.
Melting of continental Antarctic ice could contribute to global sea level rise.
Climate models predict more snowfall than ice melting during the next 50 years, but models are not good enough for them to be confident about the prediction.
Antarctica seems to be both warming around the edges and cooling at the center at the same time. Thus it is not possible to say whether it is warming or cooling overall.
There is no evidence for a decline in overall Antarctic sea ice extent.
The central and southern parts of the west coast of the Antarctic Peninsula have warmed by nearly 3°C. The cause is not known.
Changes have occurred in the upper atmosphere over Antarctica.

The area of strongest cooling appears at the South Pole, and the region of strongest warming lies along the Antarctic Peninsula. A possible explanation is that loss of UV-absorbing ozone may have cooled the stratosphere and strengthened the polar vortex, a pattern of spinning winds around the South Pole. The vortex acts like an atmospheric barrier, preventing warmer, coastal air from moving in to the continent's interior.
A stronger polar vortex might explain the cooling trend in the interior of Antarctica.
In their latest study (September 20, 2007) NASA researchers have confirmed that Antarctic snow is melting farther inland from the coast over time, melting at higher altitudes than ever and increasingly melting on Antarctica's largest ice shelf.
Scientists project that the ozone hole should fully recover by 2070.“As the ozone hole recovers, we expect that warming will appear on the central plateau of Antarctica and we will see a reduction in sea ice area,” said Turner.

Source: www.NOAA.com