Study: South American Glaciers In Historic Retreat

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"Study: South American Glaciers In Historic Retreat"

One of the more dramatic effects of global warming is shrinking glaciers around the globe. 10 to 20 percent of glacier ice in the European Alps, for example, has been lost in less than two decades, and half the volume of the mountain range’s glacier ice has melted away since 1850.

Thinning and melting rates in Alaskan glaciers more than doubled over the last decade, African glaciers have declined by 60 to 70 percent since the 1900s, and most Pacific glaciers are also receding. Summer ice coverage in the Arctic could disappear entirely within a decade, and Glacier National Park may not have any glaciers by 2030.

This isn’t just destructive to wildlife and ecosystems. Given their locations, glaciers can serve as crucial supplies of fresh water for various human populations — and as they shrink year after year, those supplies tighten.

The latest example comes from a new report by The Cryosphere, which documents the shrinkage of glaciers in the Andes mountain range of South America. The glaciers have shrunk by at least a third, and possibly as much as half, since the 1970s alone. And the worst loss has been seen in the smaller, lower altitude glaciers which supply fresh water for many of the continent’s residents, according to a round-up of the report by Reuters:

Climate change has shrunk Andean glaciers between 30 and 50% since the 1970s and could melt many of them away altogether in coming years, according to a study published on Tuesday in the journal Cryosphere.

Andean glaciers, a vital source of fresh water for tens of millions of South Americans, are retreating at their fastest rates in more than 300 years, according to the most comprehensive review of Andean ice loss so far.

The study included data on about half of all Andean glaciers in South America, and blamed the ice loss on an average temperature rise of 0.7 degree Celsius over the past 70 years. […]

The researchers also warned that future warming could totally wipe out the smaller glaciers found at lower altitudes that store and release fresh water for downstream communities.

The plot above tracks the changes in surface area for the various glaciers in the Andes since the Little Ice Age in the mid-17th to early-18th centuries. The measurements prior to 1940 were put together from studies of debris associated with the glaciers, and reconstructed from aerial photographs after that point. The drop-off in the second half of the 20th Century is precipitous.

The Zongo Glacier (the red squares) managed to avoid the dramatic shrinkage of the other glaciers because it sits at a higher altitude. The lower altitude glaciers are more vulnerable to temperature shifts, and thus have seen the worst of the melting. They’re also the glaciers that supply fresh water for both the agriculture and consumption of large populations in the arid regions of Peru and Bolivia, serving as a buffer for those communities during the dry season from May/June to August/September.

As the glaciers recede, that buffer shrinks, leaving those water supplies ever more strained. Meanwhile, the tendency of global warming to drive more extreme weather patterns could exacerbate the severity of the dry season, dealing a double blow to the people of Peru and Bolivia.

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12 Responses to Study: South American Glaciers In Historic Retreat

  1. Paul Magnus says:

    hell n high water…
    http://www.abc.net.au/news/

    Fanning the flames
    Strong winds are intensifying the strength of two bushfires burning in Victoria’s east.

    Live coverage
    Emergency services are preparing for a hectic weekend as ex-tropical cyclone Oswald dumps record rain totals on Queensland’s coast from the Capricornia south and all the way down to northern New South Wales.

    • Jack Burton says:

      Thanks for the Victoria wild fire link. Also, I live in the upper Midwest in the USA, up on the Canadian border in the northern Boreal forests. Our climate is Siberian like in normal times. But these are no longer normal times. Last summer we had a near 20 inch rainfall event in less than 24 hours, a tropical storm event. Nothing has ever been recorded up here even close to it! I know die hard climate deniers here who were shocked by this event. Now they are beginning to think, they see it, which makes denial harder and harder.

    • Paul Magnus says:

      and what are Auz planning to do in light of all this… expand their coal exports of course…

      Stop coal exports driving climate change | Greenpeace Australia Pacific
      http://www.greenpeace.org.au
      It’s distressing to see yet another extreme bush fire season. It’s ripping through our forests and farmland, forcing peoples from their homes, and putting communities, animals and fire fighters in danger.Yet at the same time as linking extreme weather to climate change, the government is approving …
      2

  2. Paul Magnus says:

    oops…

    Australians find $20 trillion oil reserve in their big backyard
    now.msn.com
    We may be the land of the free and the home of the brave, but if it’s oil you’re after, Australia’s the place to be. Linc Energy has discovered an outback oil basin estimated to contain a globe-warming reserve of up to 233 billion barrels.

    • Paul Klinkman says:

      If your country’s part in GHG pollution kills our forests and burns them up, tears big tornado tracks visible from space through our cities and destroys our subways with salt water flooding, then our country is slapping a serious trade tariff on all of your country’s exports you fiend. If 20% of all countries did this, we’d see motion on climate change. If 90% of all countries did this the problem would be reversed back below 350 ppm, even if the last country on earth to sign on was the USA.

      • Superman1 says:

        Paul says: “If your country’s part in GHG pollution kills our forests and burns them up, tears big tornado tracks visible from space through our cities and destroys our subways with salt water flooding,” How does that differ from a deliberate act of aggression, and why shouldn’t we respond the same way?

  3. jonthed says:

    Is there a chart showing the surface area in relation to the average temperature?

    Also, I’m very dismayed that news such as this is countered by simply saying “we’re coming out of an ice age, this is expected.” They sweep it aside as if it’s not related to man’s GHG emissions, and also sweep it aside without considering the huge impacts it’s going to have on millions of people around the world who depend on glaciers for water.

    A graph showing the connection between the sudden acceleration of temperature increase to the sudden acceleration of glacier loss should hopefully make the real story clear.

    • Paul Klinkman says:

      Glaciers, or the lack of glaciers, create microclimates in mountain glacier valleys. When half of the valley’s ice is gone, the brown exposed rock areas of the valley absorb heat, which heats the air, so that the rest of the valley’s glacier melts pretty fast. Mountain glaciers are also susceptible to black carbon soot particles.

      As the total square miles of reflective ice surface shrinks worldwide, mountain glacier shrinkage contributes to the overheating of the planet.

      Painting rocks white near glaciers might help to preserve them. Humidity/fog enhancement at night, especially in winter, might increase snow accumulation levels at these high elevations.

    • Jay Alt says:

      Yes jonthed, I’ve come across that reply.
      Wikipededia graph
      &
      GlobalWarmingArt graph

      also article for detailed knowledge –

      The Climate Institute article

      These show Holocene Sea Level data. The N.H. ice sheets were almost entirely melted by 7,000 years ago, Over the last 6,000 years sea levels have remained remarkably stable & hospitable to human settlement along the shores.

      I’d first concede this point – Yes, the Earth is still rebounding upward in Scandinavia, Canada & Russia, from the removal of ice sheet weight.
      But the response time of the water cycle is much, much shorter.

  4. mspelto says:

    This is an excellent paper that illustrates that the retreat is significant regardless of latitude along the Andes. This can only be accomplished by a global signal, temperature, one location or another may experience ppt changes of the same nature but not the entire range. The Cordillera Centrale of Peru is another area of widespread retreat. Please by cautious about the statement that will not prove true of all glaciers in GNP disappearing by 2030.

  5. Joan Savage says:

    According to a UCAR newsletter, several cities in the Andes depend on glaciers for about 20% of their average annual water supply, with an increased dependence developing during the dry season.

    The Andean 20% is a greater dependence on glacier melt than seen in Asian cities which receive as much as 95% of their water from monsoons with only about 5% from glacier water.

    http://www2.ucar.edu/atmosnews/water-futures/who-needs-glaciers

  6. Spike says:

    A good Facebook page for Glaciology news which I have just come across here:

    http://www.facebook.com/AUCfG