Global warming debate turns to claims over Antarctica, Greenland (click title to entry for link to The Jakarta Post)
Opinion News - Thursday, November 15, 2007
Michael Richardson, Singapore
Ban Ki-moon has ventured where no United Nations secretary-general has gone before -- to Antarctica. He flew in from Chile on Friday (Nov. 9) and on Sunday after his visit issued a statement in New York warning that the icy continent was "on the verge of catastrophe" that could trigger a sharp rise in sea level and major flooding of coastal lowlands around the world.
Ban is trying to build support for more effective international action to tackle climate change. Antarctica is currently controversial for two reasons.
First, as temperatures rise and sea ice recedes around the North Pole, countries bordering the Arctic Ocean are making competing claims to adjacent sub-sea territory that is thought to contain vast reserves of oil and natural gas.
The bordering states are Russia, Canada, the United States, Norway and Denmark (through Greenland, a self-governing Danish territory). Similar jostling has started in the Antarctic. Britain last month said it was considering lodging a claim to territorial rights over an area of the continental shelf off Antarctica covering more than one million square kilometers.
Argentina and Chile immediately confirmed that they have overlapping claims. Other countries, including Russia, Australia, New Zealand, France and Norway, had earlier lodged Antarctic continental shelf claims or reserved the right to do so. China announced this week that it would build a third research station on the White Continent and expand its scientific presence there.
In the early 1980s, scientists discovered evidence of large natural resource deposits in Antarctica, including coal, gas and oil, with the continental shelf considered to hold the region's greatest potential for oil reserves. But all territorial claims were suspended by the 1959 Antarctic Treaty.
A subsequent protocol, which entered into force in 1998, designated the region as a natural reserve devoted to peace and science. It also placed a moratorium on mining and drilling for oil or gas for a minimum of 50 years, until 2048, (when advances in technology might make exploration and extraction in such a hostile environment possible).
While the latest claims to the material riches of Antarctica are testimony to the enduring power of national interest and human greed, they are overshadowed by a second, more urgent controversy surrounding the area -- the extent to which the vast ice sheet that entombs nearly all of the continent and extends off-shore as ice shelves is melting and contributing to rising sea levels around the world.
This is a vexed issue among scientists and a major focus international polar research this year and next. The potential for global catastrophe is clear. The world's only two continental ice sheets, Antarctica and Greenland, contain over half the total amount of fresh water and around 99 percent of freshwater ice on Earth.
Scientists writing in a report commissioned by the UN Environment Programme that was published in June said that the level of oceans and seas would rise by about 64 metres if the present mass of ice in Antarctica and Greenland melted completely.
Antarctica alone would account for nearly 57 metres of the rise. Although the scientists added that this could take hundreds or even thousands of years, "recent observations show a marked increase in ice-sheet contributions to sea-level rise."
So far, the sea level increase has been small. But it is growing faster. Coastal and island tide-guage data show that sea level rose by just under 20 centimeters between 1870 and 2001, with an average rise of 1.7 millimeters per year during the 20th century. From 1993 to the end of 2006, near-global measurements made by high precision satellite altimeters indicate that worldwide average sea level has been rising by about 3 millimeters per year.
IPCC scientists give two main reasons for this: thermal expansion of ocean waters as they warm, and increase in ocean mass, chiefly from the melting of land ice.
Greenland is more susceptible to global warming than Antarctica partly because its climate is strongly affected by proximity to other landmasses and to the North Atlantic, and partly because its ice sheet is smaller and less thick. Greenland's ice extends over an area of 1.7 million square kilometers. With an average thickness of 1,600 metres, it has a total volume of about three million cubic kilometers.
This is about one ninth of the volume of the Antarctic ice sheet which covers 13.6 million square kilometers, including islands and ice shelves, and has an average thickness of about 2,400 metres. The inland ice has a depth of up to 5,000 metres, making Antarctica by far the highest of the continents.
The UNEP report said that summer melting now occurs over about half the surface of the Greenland ice-sheet particularly near the coast, with much of the water flowing into the sea. As surrounding temperatures rose, the total loss from the ice sheet more than doubled from a few tens of billions of metric tons per year in the early 1990s to about 100 billion tons per year after 2000, with perhaps a further doubling by 2005.
The report warned that Greenland, which has no ice shelves extending out from its coast, provided a picture of Antarctic conditions if the climate warmed enough to weaken or remove protective ice shelves that skirt 1.5 million square kilometers of the Antarctic coastline.
The questionable stability of Antarctic ice shelves in a warming climate was highlighted by the collapse of the Larsen B ice shelf in 2002 off the northern Antarctic Peninsula that juts out towards the tip of South America.
Scientists say that the scale of this collapse is unprecedented since the end of the last ice age. Some believe it is a harbinger of worse to come.
Since the start of the IPCC projections in 1990, the sea level has actually been rising more rapidly than the central range of its forecasts. Some scientists, worried by what they see in Greenland and Antarctica, believe that 21st century sea level rise might exceed IPCC projections and be as large as 1.4 metres.
Of the major inhabited continents, Asia would be most seriously affected. The UNEP report said that a one metre rise in sea level would inundate over 800 square kilometers of low-lying land with a population of more than 100 million people, slicing around US$450 billion from the region's current GDP.
The writer, a former Asia editor of the International Herald Tribune, is a security specialist at the Institute of South East Asian Studies in Singapore.
