Glacial melt will wreck ecosystems

Glaciers cover one-tenth of the planet’s land surface – but not for much longer.

Glaciers worldwide are in retreat, and losing mass. They are shrinking and melting, and that will create problems almost everywhere, according to new research.

Between 2003 and 2009, glaciers melted on a gargantuan scale, with an estimated 1,350 cubic kilometres of meltwater draining from what had once been vast streams of slowly flowing ice.

Ice has been in retreat in the Gulf of Alaska, the Canadian Arctic, Greenland and Antarctica. In the European Alps summers have become measurably warmer during the last 30 years, snowfall has diminished and 54% of the ice cover in the mountains has disappeared since 1850. By 2100, Alpine summits may have lost around nine-tenths of the ice that still covered them in 2003.

In South America, the glaciers of Bolivia lost almost 50% of their mass in the last 50 years. In western Canada, somewhere between 60% and 80% of the ice measured in 2005 will have disappeared, and flowed into the sea to raise sea levels everywhere.

And, says an international team of scientists, the loss of mountain ice creates problems for the people who live downstream. Ice loss upstream means changes in the timing, magnitude and frequency of the flows downstream, and that in turn affects the levels of sediment, and the nutrients, both for the human populations who depend on the farmland in the valleys and plains below, but also for the natural ecosystems in the rivers, lakes and coastal zones.

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