12 October 2009

Acronym for the day - GLOF

A glacial lake outburst flood occurs when water trapped behind or beneath a glacier suddenly breaks free.

A BBC article this weekend mentioned that for the last 11 years there has been no increase in global temperatures - even though atmospheric carbon dioxide has continued to rise - which of course delights the climate change skeptics. The article goes on to discuss solar and ocean cycles, including this startling statement:
"The PDO [Pacific decadal oscillation] cool mode has replaced the warm mode in the Pacific Ocean, virtually assuring us of about 30 years of global cooling."
I thought that was most interesting, since Minnesota/Wisconsin is presently experiencing distinctly unusual early-October snow. Weather, of course, is not climate, and the article concludes by noting that even though the Intergovernmental Panel on Climate Change says that cooling worldwide temperatures could last another 10-20 years, the long term trend would still be upward.

Somehow I then wandered over to The Guardian, where Himalayan sherpas are complaining that warmer temperatures have allowed houseflies to arrive at Everest base camp at an altitude of over 5000 meters (attracted no doubt by the world-class feces spread around the landscape).

The sherpas note that glaciers around Everest are shrinking, as is the snowcap. This is making it more difficult for climbers to gather for photos at the summit:
"Also the summit is getting smaller. You used to be able to get 50 people on the ridge to it. Now there's room for 18 people at most. The cornice is breaking off. A big crevasse is opening. It never used to exist. It seems nothing is safe anymore."
And finally we learn about GLOFs:
"A glof happens when a glacial lake is created by a melting glacier and it then bursts. Imja lake is the most dramatic example of a potential one. It is growing 74m a year. When it bursts its banks, we will have a mountain tsunami. Billions of gallons of water will be released and it could wipe out about 70% of the trekking trail to Everest base camp. Not only will that destroy our homes and potentially kill people, but it will wipe out the jewel in the crown of Nepal's tourism industry."
GLOFs were responsible for the creation of what is today the Minnesota River when glacial Lake Agassiz drained at the end of the ice age.

7 comments:

  1. Cool! I didn't know there was an acronym for it.

    GLOFs were also responsible for carving out the Columbia River Gorge that divides Washington and Oregon. The stats on those floods are mind-boggling. There were around 40 of them (evidence found for at least 25), averaging once every 55 years. Each one contained up to 10 times the total flow of all the rivers in the world (or 60 times the flow of the Amazon), moving at a speed of 30-60 mph, depending on terrain. The wall of ice, water, mud and boulders was up to 500 feet high, pushing a hurricane-force wind in front of it. It created a temporary waterfall in eastern Washington that stretched five times the width of Niagara.

    Every flood would have covered the entire city of Portland, Oregon except for the top few floors of the tallest building. They built up a sand bar near Portland that created a 70-mile-long lake, which would have been larger than San Francisco Bay.

    They're now called the Bretz Floods, named after the geologist who, without benefit of satellite or even aerial photography, figured out the history simply by walking over some of the terrain. For his efforts he was vilified by his peers, because he was offering a theory in direct opposition to the accepted way of thinking. He spent his entire life fighting for recognition of his results, and was finally recognized by the Geological Society of America at the age of 96.

    The closest modern comparator we have to the sort of terrain-altering destruction caused by the Bretz Floods is Mt. St. Helens, which destroyed or altered 150 square miles. The Bretz Floods affected 16,000 square miles.

    Check out J Harlen Bretz. I think he's probably your kind of guy.

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  2. "which of course delights the climate change skeptics."
    It should delight skeptics, as well as those invested in gloom and doom.

    Yeah the Missoula floods, I've never heard them called the Bretz floods, (perhaps that's the proper name) must have been fantastic.

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  3. I highly recommend Kim Stanley Robinson's climate change trilogy.

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  4. This article is horrible. Someone did a terrible job at the BBC.

    http://www.grist.org/article/global-warming-stopped-in-1998/

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  5. There's also this one:
    http://www.realclimate.org/index.php/archives/2009/10/a-warming-pause/

    I think an addendum to this post is more than warranted. Anthropogenic global warming is an undeniable fact, and it is articles and blog posts like this which make the scientists' job and the sane, informed policymakers' job much much harder.

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  6. Anonymous;
    That is why we make these posts isn't it, to make scientists and policy makers jobs that much harder! If it were easy, it wouldn't be worth discussing would it.

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  7. I live at the western end of a giant gravel bar in Portland, called the Alameda ridge. It's a remnant of the Missoula floods, apparently. People on the uphill side of the ridge all have massive collections of round river rocks in their soil even though we're at least two miles from the Columbia river.

    link
    http://en.wikipedia.org/wiki/Alameda_Ridge

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