By Alister Doyle, Environment Correspondent

OSLO, Feb 13 (Reuters) - Arctic summer sea ice is unlikely to shrink drastically in 2008 beyond a record low set last year even though the long-term trend is a thaw tied to global warming, a leading scientist said on Wednesday.

Arctic sea ice, an indicator of climate change as it expands in winter and thaws in summer, shrank last September to a low of 4.1 million sq km (1.6 million sq miles), more than 1.2 million sq km less than the previous recorded low in 2005.

"My feeling is that the situation will probably be the same as last year, or maybe a slight recovery," Jean-Claude Gascard, head of the European Arctic research project Damocles, told Reuters.

"I would be very surprised if there would be another large drop this year. It would be really dramatic," said Gascard, of France's Universite Pierre et Marie Curie.

Some experts project that the ice could vanish in summer by mid-century, threatening the hunting livelihoods of Arctic indigenous peoples and species such as seals and polar bears while opening the region to oil and gas exploration or shipping.

Gascard said informal surveys by Damocles of scores of leading researchers, at meetings in San Francisco and in Oslo in recent months, showed that a large majority also expected the ice in 2008 to be unchanged from 2007 or slightly bigger.

"Very few said that there will be another drop as large as it was last summer," he said. The melt can accelerate climate change because tracts of darker water soak up far more of the sun's heat than reflective snow and ice.

"Rarely is there a drop of such magnitude in two consecutive years," he said of historical data, adding that the extreme 2007 thaw may be partly explained by natural variability rather than global warming alone.

TIPPING POINT

Any surprise new fall to a record low would be a worrying sign that the ice had crossed a point of no return, a "tipping point" that could herald an accelerated disappearance of the ice.

"If we have two years in a row with a drastic drop in the ice extent at the end of the summer ... it would be a strong argument for having crossed a tipping point," he said.

The U.N. climate panel says it is more than 90 percent likely that human activities, led by burning fossil fuels, are to blame for a warming projected to bring more floods, droughts and rising seas.

-- For Reuters latest environment blogs click on: http://blogs.reuters.com/environment/ (Editing by Peter Millership)

AlertNet news is provided by