Global Warming: Getting off the shelf

Michael Richardson, Straits Times 10 Nov 07;

You know that global warming has become a truly international issue when United Nations Secretary-General Ban Ki Moon gets involved

MR BAN Ki Moon is venturing where no United Nations secretary-general has gone before - to Antarctica. Weather permitting, he will fly from Chile and spend this weekend talking to some of the international scientists based in the icy continent.

It may seem odd that Mr Ban, a former South Korean foreign minister, has chosen to visit a desolate land mass roughly twice the size of Australia that belongs to no country, is not a UN member and has a maximum resident population of only several thousand during the few short months of the frigid 'summer' that is just beginning around the South Pole.

Yet Mr Ban's trip is well-timed and has been carefully chosen. It is part of a political eco-tour that will also take him to Spain and the Indonesian island of Bali over the next few weeks.

In the Spanish city of Valencia on Nov 17, the Intergovernmental Panel on Climate Change (IPCC) - a group of some 2,500 researchers from over 130 nations set up in 1988 to study global warming - will release its latest assessment report.

The IPCC was last month awarded the Nobel Peace Prize, along with Mr Al Gore, the former US vice-president turned climate campaigner.

In Bali, UN member states will try to hammer out terms for a successor agreement to the Kyoto Protocol. It contains legally binding targets for reducing man-made emissions which the IPCC concluded earlier this year were very likely responsible for most of the global warming in the past 50 years. The Kyoto accord does not include all of the big emitters and will expire in 2012.

Hot ice

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 1 million sq km. Argentina and Chile immediately confirmed that they have overlapping claims. Other countries, including Russia, Australia, New Zealand, France and Norway, have lodged earlier 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 came 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 offshore 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 of 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 per cent 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 64m if the present mass of ice in Antarctica and Greenland melted completely.

The Great Flood

ANTARCTICA alone would account for nearly 57m 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- gauge data show that sea levels rose by just under 20cm between 1870 and 2001, with an average rise of 1.7mm 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 rose by about 3mm per year.

IPCC scientists give two main reasons for this: thermal expansion of ocean waters as they warm, and an 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 land masses 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 sq km. With an average thickness of 1,600m, it has a total volume of about 3 million cubic km.

This is about one-ninth of the volume of the Antarctic ice sheet, which covers 13.6 million sq km, including islands and ice shelves, and has an average thickness of about 2,400m. The inland ice has a depth of up to 5,000m, 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 tonnes per year in the early 1990s to about 100 billion tonnes 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 sq km 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.

The latest IPCC assessment report projects a sea level rise by the end of this century of between 18cm and 59cm. A major uncertainty is the contribution that ice sheet melting will make. Since the start of the IPCC projections in 1990, the sea level has actually been rising more rapidly than the central range of 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 1.4m.

Of the major inhabited continents, Asia would be most seriously affected.

The UNEP report said that a 1m rise in sea level would inundate over 800 sq km of low-lying land with a population of more than 100 million people, slicing around US$450 billion (S$650 billion) off the region's current GDP.

The writer is a security specialist at the Institute of Southeast Asian Studies. This is a personal comment.