LOS ANGELES, June 3 (Xinhuanet) -- Arctic lakes have been disappearing for the last 30 years, probably in response to thawing permafrost linked to global warming, according to a new study published on Friday.

    

Arctic lakes have been disappearing for the last 30 years, probably in response to thawing permafrost linked to global warming, according to a new study published on Friday.

In a paper in the June 3 issue of the journal Science, US researchers analyzed satellite observations of more than 10,000 lakes in Siberia.

    They found the number of large arctic lakes has decreased from 10,882 to 9,712 between 1973 and 1998. A total of 125 lakes vanished completely while the rest have decreased in surface area.     

    Initial permafrost warming triggers the development of collapsed land formations called "thermokarsts." Additional warming degrades the permafrost further, leading to permafrost "breaching" which may greatly facilitate the drainage of nearby lakes into the subsurface, the authors suggest.

    The researchers also reported an increase in total lake area innorthern Siberia, suggesting a possible beginning of permafrost degradation in the future.

    "This is the first paper that demonstrates that the changes we are seeing in Alaskan lakes in response to a warming climate is also occurring in Siberia," said Larry Hinzman, a co-author from the University of Alaska.

    Laurence Smith, lead author of the paper at the University of California, Los Angeles, said they were surprised by the overall loss in surface water.

    "We were expecting the lake area to have grown with climate change," said Smith. "And while it did do so in the north where the permafrost remains intact, lake area did not increase in the south where permafrost is warming."

    In permafrost regions, summer thaw produces meltwater, which istypically unable to infiltrate into the ground because of the ice-rich frozen soils found in permafrost. Data gathered from the latest measurements indicate that warming temperatures lead to increased numbers of surface water bodies in the colder permafrostregions.

    Many lakes decreased in size or dried up completely, while other lakes actually increased in size. Researchers said as the climate warms, additional meltwater accumulated in the lakes located in the colder regions of thicker permafrost increase theirsize; however, if climate warming continues, even those lakes would eventually be susceptible to loss.

    "We expect areas of continuous permafrost to continue to thin and move steadily northward, resulting in the disappearance of more lakes," said Smith.

    In regions with thin or discontinuous permafrost, surface soilsalso become drier as the permafrost degrades.

    "The changing lakes are a consistent, measurable indication of the overall changes to hydrology in the Arctic," said Hinzman.

    "The loss of surface water will inevitably impact local ecosystems, which will have a cascading effect. Changes could include loss of migratory bird habitat resulting in an effect on subsistence activities as well as changes to local and regional atmospheric conditions, including more localized wind and more frequent and more severe wildland fires." Enditem