Sunday, November 25, 2012

 
We as a nation are experiencing drastic changes to our environment, most of us believe we are going through global climate warming, but some argue that it is not true. If we stop and look at the glaciers around the world we would be able to see that due to temperatures rising they are melting at alarming rates. In South America risings temperature are melting ice caps and glaciers at such fast rates that the communities living off the glaciers will find themselves without water and income. It is not just the communities that are implemented by rising temperatures, but biological life as well. NASA and other research has been conducted watching South America’s retreating glaciers, following sea level rise, and the economic problems that are going to come up as the glaciers melt away.  


http://sprinterlife.com/2011/06/the-door-to-the-
andes-the-longest-mountain-range-in-the-world.html
South America has a total of 79 named glaciers and over 23,000 km2 of land covered by them. Those areas make it the largest glacial region in the southern hemisphere (not including Antarctica) (Casassa, 2011).  In this region there are both alpine glaciers that reach altitudes of 6000m and then there are ice sheets that are located at sea level (Mariano,p 242). The alpine glaciers are in the Andes Mountains of Bolivia, Colombia, Ecuador, Peru, Venezuela, in north Argentina and Chile. The sea level glaciers are in the southern portions of Chile. In order to form a glacier it needs to be in a location where it has cool temperatures and high amounts of precipitation generally in the form of snow. The snow needs to accumulate over a period of time, the accumulated snow is called firn, snow that has lasted through one summer season. Firn will accumulate additional snow on top of it. This process allows for the firn to gain pressure, pressure creates movement and growth, then the snow on top will melt creating metamorphic snow that will then refreeze. The refreezing expands the ice. This process needs to occur several times over many snow periods to have a healthy moving glacier. In the summer when the glacier will begin creating “new” firn it needs to at least have the same amount melting as it did accumulate over the winter. If the snow ablation is more than the accumulation the glaciers will tend to melt more and then will eventually shirk melting away and could turn into a tarn or runoff just runoff in to rivers and the ocean. But if the accumulation is the same or more than the ablation the glacier will be stable. The mass balance of a glacier is the accumulation minus the ablation; a “sick” glacier will have a negative mass balance and a “healthy” glacier will have a positive mass balance.  The problem in the cases of the South America’s glaciers is that in general the snow is not able to turn into firn.  There mass balance is zero or in the negative numbers indicating that these glaciers are melting.





This was from ITN World News
Watching the collapse of Argentina's Perito Moreno Glacier 
 
South American glaciers are unique because many of them are affected by tropical weather patterns. A research project was conducted by Mariano Masiokas, Andres Rivera, Lydia Espizua, Ricardo Villalba, Silcia Delgado, and Juan Aravena that looked at the glacial fluctuation in tropical regions of South America over a 1000 year period. The reason that the South American glaciers are unique compared to those of the Northern Hemisphere glaciers is that they are located in an extratropical region in the Andes Mountains, where they experience hot humid weather during the summers and precipitation in the winter. Figure 1 shows circulation patterns of the jet streams and polar deserts where South America's glaciers are located. The data collected helped reconstruct the glaciers that were previously thereas well as the growths and retreats of many glaciers. The data also was able to present how weather patterns, precipitation, and topography affect current and past glaciers. When looking at the glaciers in South America the snow line decreases as you move east to west and north to south. Figure 2a shows the mean annual precipitation; the mean precipitation is dropping from approx. 400 mm in the NW to approx. 100 mm in the SE (Masiokas, p. 243). The mean annual temperatures is shown in Figure 2b; the mean temperature is dropping from warmest in the north and coolest in the south.   









Figure 2a: Mean Annual Precipitation
 http://www.scientificjournals.org/journals2007/articles/1061.htm

Figure 2b. Mean Annual Temperature
http://www.scientificjournals.org/journals2007/articles/1061.htm






One of the most studied and visited places to go in South America is the Patagonia Icefields which has a total of 3 main areas the Northern Patagonia Icefield, Southern Patagonia Icefield, and Cordillera Darwin (Casassa, 2011). In 2011 the Northern Patagonia Icefield was 4,200 km2, the Southern Patagonia Icefield was 13,000 km2, and Cordillera Darwin was 2,000 km2; combined they cover roughly 19,200 km2 of land that is covered in ice and snow. (Casassa, 2011). Icefields/ caps generally move outward from a central point in all direction; whereas the alpine glaciers move downwards through the valley. These 3 icefields are located in the polar desert region of South America, but are some of the largest icefields in the Southern Hemisphere.  


Then and Now taken from of the Upsala Glacier in Patagonia
 http://www.changeclimate.org/mountain-glaciers-are-melting/

The southern Patagonia icefield according to Michael Willis and colleagues is said to loss 20 billion tons of ice each year. They went on to find out that it is 9,000 time greater than our Hoover Dams water stored and that if over a 12 year period if the water was to be captured it would be able to cover the entire united states with 2.7 cm of water. This scientific study was done by M. Willis et al over 12 years by using 156 satellite images and Shuttle Radar Topography Mission data to calculate the icefields loss(Willis,2012). His data has shown that the melt from the icefield is indeed rising sea level by a significant amount. NASA reported that 10 percent of the water added into the ocean is from the mountain glaciers in South America (Steitz, 2003). Even more astonishing the report went to show that from 1975-1995 the water add was 0.04 mm and the amount of water imputed into the ocean from glaciers doubled from 1995-2000 to 0.1 mm (Steitz,2003). The research from NASA and Willis have proved that the icefields and glaciers are thinning at alarming rates and this is, in these area due to warming temperature. As temperature increase it is not only the heat that will change a glacier or that it stops precipitation, but the warming temperature do not allow it to make snow instead it will fall as rain. They are also starting the spring season quicker and the fall season is lasting longer. The tropical areas are still getting precipitation and that means that during the spring, summer, and fall the glaciers are having more rain. Rain for a glacier is the ultimate destruction. When a glacier is forming it goes through several metamorphic stages. As the temperatures being to warm the rain on top of the glacier begins to peculate down and it will then stop at a point in the glacier that  is below 32 degrees F. That will then  refreeze the water, we call that area where this occurs  the saturation line. However the glaciers are not as cold anymore due to a warmer winter, so the water percolating is putting more holes into the glacier. The holes are scooping the glacier and around those holes the glacier is melting because of latent heat. It is the ultimate end of glaciers to have warm temperatures most of the year and then have rain instead of cool snowy temperature during the spring and fall months. Climatologist have been studying many of the glaciers that are having warmer temperatures in the winter and finding out that the glaciers that have a warmer winter by just a few degrees are melting even quicker. (Frederick Chambers lecture)



This Youtube video is presented by INT World News
Talking about the melting glaciers in Patagonia.


http://www.theclimatehub.com/mountain-glacier-changes-since-1970


The UN in December 2010 came out and said the glaciers are melting the fastest in Alaska and in southern South America and that the communities will need to quickly adapt to the melting glaciers. The Washington Post released an article on January 16, 2011 reporting that the retreating Alpine Glaciers in Peru are having an effect on the wildlife, crops, and villages that need the water runoff from the glaciers. Peru has one of the largest Alpine Tropical glaciers in the world and the yearly runoff from it was supplying more than water, but helping with irrigation and electricity. The post went on to say that some scientist are expecting that all the tropical glaciers in the region will be gone within the next 10 years, due to warming temperatures. The U.S. Agency for International Development gave over a 1.25 million dollar grant to The Mountain Institute so they could start helping communities adapt to the melting glaciers and new ways of living once these glaciers are gone. 


Presented by The World Bank: Peru
Explaining the drastic effects melting glaciers are having currently on communities
and the dangers they will have many communities in the future.

Work Cited:
-Liu, Kam-biu, Carl Reese, and Lonnie Thompson. "Quaternary Research." Quaternary Research. 64.7 (2005): 272--278. Print.
-Maskiokas, Mariano, Andres Rivera, Lydia Espizua, Ricardo Villalba, Silvia Delgado, and Juan Aravena. "Glacier fluctuations in extratropical South America during the past 1000 years." Paleogeography, Paleoclimatology, Paleoecology. 281.3-4 (2009): 242-268. Print.
-Le Roux, J.P. “A review of Tertiary climate changes in southern South America and the Antarctic Peninsula. Part 2: continental conditions.” Sedimentary Geology. 247-248. (2012): 21-38. Print.
-Steitz, David, Alan Buis, and Claudia Adriasola. United States. NASA. South American Glaciers Melting Faster, Changing Sea Level. Washington: NASA News, 2003. Web. http://www.nasa.gov/home/hqnews/2003/oct/HQ_03336_So_Amer_glaciers.html .
- Willis, Michael, Andrew Melkonian, and Matthew Pritchard. “Glacial thinning has sharply accelerated at major South American icefields.” AGU. 12-41. 05 Sep 2012. Web.  http://www.agu.org/news/press/pr_archives/2012/2012-41.shtml .
-Casassa, Gino. “South American glaciers on the retreat.”  The Environment Times. Web. http://www.grida.no/publications/et/pt/page/2565.aspx .
-Nicholson, Sophia. “Glaciers melting fastest in South America, Alaska: UN.” AFP. 07 Dec 2012. Web. http://www.google.com/hostednews/afp/article/ALeqM5h-jbbqLoUD5YVvm99RvtA8WBn-Pw?docId=CNG.49306581e9fc80d84d7a1d3b2187e6cc.551 .
-DailyClimate.org. “Patagonian Glaciers Melting in a Hurry.” Scientific America. 06 Sep 2012. Web. http://www.scientificamerican.com/author.cfm?id=3184 .
-Aguirre, Jessica. “As Glaciers Melt.” Yes Magazine. 18 Mar 2010. Web. http://www.yesmagazine.org/planet/as-glaciers-melt-bolivia-fights-for-the-good-life .
-Urbaitel, Jose. “El Chalten: a Pearl in Southern Patagonia, Argentina.” PSA Journal. 78.9 (Sep 2012): 38. Print.
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