Ice streams are moving huge amounts of ice into the oceans from the centre of Antarctica-a continent three-quarters as large as North America.
by Bruce Torrie
The possibility of a substantial sea level change was made all too clear in a recent article in Climate Alert, the newsletter of the prestigious Climate Institute of Washington, DC. In that publication, researchers examined the potential for a breakup of the already two-thirds-collapsed west side of Antarctica, the West Antarctic Ice Sheet (WAIS), and the chance of a six-metre increase in the global sea level.
The WAIS was home to the recently collapsed Ross Ice Shelf – approximately 20,000 sq km – which collapsed in early December 1997. In January 1998 the Larsen B Ice Shelf – also about 20,000 sq km – began its final stages of collapse. The Vancouver Sun reported in February, "British scientists warned that the massive Larsen B Ice Shelf is breaking up in Antarctica because of rapid rises in temperature associated with global warming. The British Antarctic Survey says the 20,700 sq-km ice shelf is 'critically unstable' and may collapse during the next two years. Such an event could alter the warm Gulf Stream ocean current, affecting the climate as far away as northern Europe."
CNN broadcast a story in July of 1998 which said American scientists were predicting the rapid breakup of the WAIS, and a 20-ft global sea level increase as the Pine Island Ice Shelf collapsed. Jet Propulsion Lab scientists say the ice shelf retreated at 1.5 km. a year between 1992 and 1996. Apparently, the Pine Island Ice Shelf is the last buttress stabilizing the WAIS.
The stability of the WAIS was discussed in the May-June issue of Climate Alert which also speculated on the possibility of the destabilization of the much larger East Antarctic Ice Sheet, and the potential for a further 60-metre sea level increase. It said the collapse of the West Antarctic Ice Sheet would leave the East Antarctic Ice Sheet (in an area just three or four degrees from the South Pole) with no support. The East Antarctic Sheet would be destabilized in a quite dramatic way. If the remaining one third of the West Antarctic Ice Sheet collapsed, there would be very large gaps in the Transantarctic Mountains, where the ice would come flooding through into the sea. So collapse of the WAIS is not only important for the six metres it would raise the global sea level – it would also free a large area of East Antarctic ice which would then enter the sea.
So how fast is all of this going to happen? Teams of scientists (Nova, PBS) observed that "ice streams" (fast-moving parts of glaciers) were moving much faster than had been previously observed. The ice streams move vast amounts of ice from the central part of the Antarctic Continent, an area three-quarters the size of North America, into the oceans surrounding Antarctica.
The scientists designed a steam drill that allowed them to drill through the three-quarter-mile-thick, rapidly moving ice stream, and sample the base, where they were surprised to find water and mud, which was lubricating the base, allowing the ice to move much faster than ever before.
And what was the source of the water and mud? Further investigation disclosed that a massive volcano was erupting beneath the ice, slightly west of the Transantarctic Mountains, sending cubic miles of hot water and mud under the already critically unstable WAIS. The scientists reported that further investigation disclosed that the two geological plates which support Antarctica, which in the distant past collided to form the very high Transantarctic Mountains, "are now separating."
In light of this alarming new data it seems reasonable to relocate one's family, food stores, and assets well above sea level. Unfortunately, 90 percent of the world's food production currently occurs within five metres of sea level.
* For more information, contact: Climate Institute, 324 Fourth Street, NE, Washington, DC www.climate.org
[From WS August/September 1998]