Posted by: shipbright | October 29, 2009

Climate change and freshwater part 2…Disappearing glaciers

I have seen many glaciers and they are truly impressive in their size, silent strength and ability to literally change landscapes. I’ve seen them in the Rockies, the Alps, Iceland, flying over Greenland, and most recently in Alaska where, like the Great Land itself, they make them big! 

Tidewater-Glacier

But perhaps nothing has ever taken my breath away than the snowpack and glacier of Mount Kilimanjaro.  Rising out of the Serengeti Plain alone in its majesty Mt. Kilimanjaro is a sleeping volcano and its sight fills the landscape.   It is even more impressive and awe-inspiring in person than any picture can do justice to.  Ever since I had read Ernest Hemingway’s “Snows of Kilimanjaro” the mountain has held for me the lure of the exotic, the impressiveness of its permanence, and seemingly improbable contrast of its snow-capped peak surrounded by the arid equatorial plains and wildlife of the Serengeti.

kilimanjaro

But the snows of Kilimanjaro and glacier have been retreating.  Scientists believe it is a direct result of global warming, not necessarily from rising temperatures at the summit but in changes to the hydrologic cycle and precipitation in East Africa and the Indian Ocean.  The loss of water from seasonal snow melt with its metered out melting holds dire consequences for those living in and around the arid iconic landscape of the Serengeti.

kilimanjaro ice lossWorldwide we are losing glaciers and ice sheets at rates we have never seen before.  These glaciers and their snowpack with their seasonal cycle of melting and accrual are important sources of freshwater for the environment’s that they are in.  In addition to the water they provide for humans, the amount and timing of water in the streams in the spring run-off has major implications for the spawning cycle of many fish species.

As you have read in earlier posts the world’s glaciers and ice sheets hold about 75% of the world’s freshwater.  Greenland and Antarctica hold the greatest amount of freshwater in their ice sheets and glaciers and their melting is cause for concern of rising sea levels.

The melting of sea ice does not appreciably add to sea level rise as the volume of the frozen freshwater is already in the ocean…glaciers melting over land, especially in Greenland, do contribute to sea level rise.  Sea ice and glacier melting causes a loss of our global reflective surface from the white ice known as “albedo”.  The loss of this surface reflectivity allows for more solar radiation absorption by the newly exposed land and ocean and contributes to more warming and melting.  Not good.

There are a number of stunning videos on Greenland’s loss of glaciers on YouTube that I recommend you surf.  Here is a video on the Greenland deglaciation done by a BBC crew at a NASA research site:

The Climate Institute at  www.climate.org provides a good primer for understanding deglaciation and sea ice melting:

“One of the most pronounced effects of climate change has been melting of masses of ice around the world. Glaciers and ice sheets are large, slow-moving assemblages of ice that cover about 10% of the world’s land area and exist on every continent except Australia. They are the world’s largest reservoir of fresh water, holding approximately 75%.

greenland ice lossOver the past century, most of the world’s mountain glaciers and the ice sheets in both Greenland and Antarctica have lost mass. Retreat of this ice occurs when the mass balance (the difference between accumulation of ice in the winter versus ablation or melting in the summer) is negative such that more ice melts each year than is replaced. By affecting the temperature and precipitation of a particular area, both of which are key factors in the ability of a glacier to replenish its volume of ice, climate change affects the mass balance of glaciers and ice sheets. When the temperature exceeds a particular level or warm temperatures last for a long enough period, and/or there is insufficient precipitation, glaciers and ice sheets will lose mass.

One of the best-documented examples of glacial retreat has been on Mount Kilimanjaro in Africa. It is the tallest peak on the continent, and so, despite being located in the tropics, it is high enough so that glacial ice has been present for at least many centuries. However, over the past century, the volume of Mount Kilimanjaro’s glacial ice has decreased by about 80%. If this rate of loss continues, its glaciers will likely disappear within the next decade. Similar glacial meltbacks are occurring in Alaska, the Himalayas, and the Andes.

melting_glacier_1When researching glacial melting, scientists must consider not only how much ice is being lost, but also how quickly. Recent studies show that the movement of ice towards the ocean from both of the major ice sheets has increased significantly. As the speed increases, the ice streams flow more rapidly into the ocean, too quickly to be replenished by snowfall near their heads. The speed of movement of some of the ice streams draining the Greenland Ice Sheet, for example, has doubled in just a few years. Using various methods to estimate how much ice is being lost (such as creating a ‘before and after’ image of the ice sheet to estimate the change in shape and therefore volume, or using satellites to ‘weigh’ the ice sheet by computing its gravitational pull), scientists have discovered that the mass balance of the Greenland Ice Sheet has become negative in the past few years. Estimates put the net loss of ice at anywhere between 82 and 224 cubic kilometers per year. 

In Antarctica, recent estimates show a sharp contrast between what is occurring in the East and West Antarctic Ice Sheets. The acceleration of ice loss from the West Antarctic Ice Sheet has doubled in recent years, which is similar to what has happened in Greenland. In West Antarctica, as well as in Greenland, the main reason for this increase is the quickening pace at which glacial streams are flowing into the ocean. Scientists estimate the loss of ice from the West Antarctic ice sheet to be from 47 to 148 cubic kilometers per year. On the other hand, recent measurements indicate that the East Antarctic ice sheet (which is much larger than the West) is gaining mass because of increased precipitation. However, it must be noted that this gain in mass by the East Antarctic ice sheet is nowhere near equal to the loss from the West Antarctic ice sheet.  Therefore, the mass balance of the entire Antarctic Ice Sheet is negative.

The melting back of the glaciers and ice sheets has two major impacts. First, areas that rely on the runoff from the melting of mountain glaciers are very likely to experience severe water shortages as the glaciers disappear. Less runoff will lead to a reduced capability to irrigate crops as freshwater dams and reservoirs more frequently go dry. Water shortages could be especially severe in parts of South America and Central Asia, where summertime runoff from the Andes and the Himalayas, respectively, is crucial for fresh water supplies. Also, in areas of North America and Europe, glacial runoff is used to power hydroelectric plants, sustain fish runs and irrigate crops as well as to supply the needs of large metropolitan areas. As the volume of runoff decreases, then the energy, urban, and agricultural infrastructures of such locations are likely to be stressed.  In addition, the melting of glaciers and ice sheets adds water to the oceans, contributing to sea level rise…”

 Snows_of_kilamajaroCommentary:  In Ernest Hemingway’s book, “The Snows of Kilimanjaro” there is a brief reference at the beginning of the novel about the presence of a frozen leopard’s carcass near the summit of Kilimanjaro.  What the Leopard was doing at such an altitude and why it was there is not explained but it becomes a focal point of Hemingway’s use of symbolism.

In the story there are two animals used by Hemingway to symbolize our own life challenges between the black and hollow eyes of death [the hyena] and a passionate strong graceful life [Leopard].  Hemingway writes what he knows like all great writers.  When I was in East Africa at the foot of Kilimanjaro I saw hyenas at night and when I flashed a light on them their eyes never reflected back the light like other creatures.  Black hollow eyes.  It was haunting.  One morning while camped out in the Serengeti a leopard attacked and ate a baboon in a tree right over my tent.  Scared the hell out me…the leopard was so graceful and rippled with such strength. 

In the book Hemingway says the name of Kilimanjaro means “House of God”.  The symbolism of the leopard guarding the “House of God” finds its symbolic inspiration in the leopard that guards Mount Purgatory in Dante’s Divine Comedy. 

Before us today are the retreating snows of Kilimanjaro as well as retreating glaciers and polar ice sheets.  I can’t help but wonder if the Polar Bear is the arctic equivalent of the Leopard of Kilimanjaro reminding us as the guardian of the “House of God” that before us is a choice of paths:  Paradisio or Inferno. 

Global_Warming_polar_bear 

…We are in our own collective global Purgatory and our actions will decide our future path…

next post:  rising sea levels, freshwater, and small island nations…

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Responses

  1. Heal the World
    and stop global warming….!
    To better future!

  2. Does anyone know if the tree of life project is involved with engineers and Mt. Kilimanjaro?


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