The glaciers of the Antarctic Peninsula down

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An Anglo-American team in the journal Science reveals that coastal glaciers of the Antarctic Peninsula have lost ground over the last fifty years.

Researchers from the British Antarctic Survey (BAS) and the US Geological Survey (USGS) analyzed more than 2000 aerial photographs taken between 1940 and 2000 and a hundred satellite images dating back to 1960 years to present (via Argon , Landsat 1, 2, 3, 4 and 5 MSS, Landsat TM 4 and 5, 1 and 2 ERS, RADARSAT and ASTER).

This helped to map with a resolution of the order of thirty meters and a positional accuracy of about 130 meters. Of the studied glaciers 244, 87 600% declined meters on average since the 1950 years (the other, irregularly distributed, with slightly increased), at a rate that is accelerating 50 meters per year for five years.

In fact, 1945 in 1954, 62% of these glaciers were growing, but the trend has changed from 1954 to achieve a retirement rate of 75% in 2004 (percentages based on average changes calculated with 95% of trust). The American Jane Ferrigno and his colleagues also noted a distinct difference depending on the location of the glaciers, those located in the northern part of the peninsula (warmer) being the most affected by the melting. Specifically, considering the isotherms to -5 -9 ° C and ° C as known in 2000, the glaciers in the coldest area were unchanged, those between -5 ° C -9 ° C decreased, whereas there is none in the hottest area (beyond -5 ° C). This particular distribution induces a link with atmospheric warming experienced by the area since 1950 (+ 2 ° C), but the team is cautious and does not want to make this warming solely responsible for the glacier retreat (of as a slowing of decline in certain areas between 1985 and 1994 not match any on cooling). Response mechanisms of these ice monsters to climate change are indeed complex and other parameters must be considered, such as ocean temperature and the amount of rainfall.

There remains a clear conclusion: the retreat of Antarctic glaciers is superior to what we thought.

WP 22 / 04 / 05 (Study Says Antarctic glaciers are shrinking, sea levels May
climb) / FT 21 / 04 / 05 (Retreat of Antarctic ice gathers pace)


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