Polar pressures

Abstract

The Arctic ice is thinning and tourists are presenting a growing problem in the increasingly fragile Antarctic environment. Nigel Williams reports. The Arctic ice is thinning and tourists are presenting a growing problem in the increasingly fragile Antarctic environment. Nigel Williams reports. The retreat of Arctic summer sea ice has been dramatic in recent years as recorded by satellite images. But it also appears that the thickness of ice has also experienced equally significant shrinkage. Most computer models predict ice-free summer conditions by 2040 to 2100 but real conditions appear to be moving faster than this. The British Catlin Arctic Survey, which got underway in February, is attempting to gather key new data about the state of the ice in winter and early spring, when the ice reaches its greatest extent. The expedition is making measurements of ice thickness along more than a 1,000 kilometre track from northern Canada to the North Pole. It is hoping to give scientists the very latest ‘ground truth’ to better inform computer models and their interpretation of the observations coming from satellites. “No other information on ice thickness like this is expected to be made available to the scientific community in 2009,” said Wieslaw Maslowski, a science adviser to the survey, who is affiliated to the US Navy Department of Oceanography at the Postgraduate School in Monterey, California. He will use the Catlin observations and the latest meteorological data with an Arctic ice model. “It is commonly agreed in the community that the ice thickness distribution at the spring determines the amount of summer melt occurring in the middle of September, where we reach the minimum ice extent based on satellite observations,” he said. The team, unsurprisingly, have met many physical problems in their expedition. After failure with their portable radar Sprite, the instrument that measures the thickness of the ice, and a fault with the SeaCat probe, a device that measures the water column beneath the floating ice, “I'll be resorting to the old tried and tested means of manual labour to get data for the scientists,” said Pen Hadlow, one of the expedition members. “It's a disappointment, but I'm not surprised — I'm hoping that at least a new SeaCat will come out on the next resupply.” The team report that they initially covered predominantly first-year ice with just a scattering of multi-year ice floes. The team are now moving into an area of predominantly second-year ice — that which has survived a summer warming. Preliminary results suggest that the extent of multi-year ice is much reduced and now confined to a narrow swathe east of 130W along the north-west Canadian Arctic archipelago and Greenland coast.The 28 countries who have signed the Antarctic Treaty agreed at a meeting last month to limit access to the continent in the future to help preserve the delicate environment The 28 countries who have signed the Antarctic Treaty agreed at a meeting last month to limit access to the continent in the future to help preserve the delicate environment While data are being gathered on the increasingly fragile Arctic ice sheet, interest in the Antarctic is growing as it suffers many of the problems of the northern Pole under climate change. Human interest in the extraordinary and increasingly fragile ecosystem there is soaring. Tourist numbers have risen from 6,700 in 1992 to more than 45,000. The 28 countries who have signed the Antarctic Treaty agreed at a meeting last month to limit access to the continent in the future to help preserve the delicate environment. Cruise ships carrying more than 500 passengers will not be allowed to land anyone. Other, smaller boats will be allowed to land up to 100 people at any one time, in an attempt to limit damage. The rapid growth in tourism has alarmed environmentalists in many of the signatory countries keen to protect a region under threat from climate change that is home to several penguin and seal species and is a vital feeding ground for many whales.