Polar essay

Páginas: 9 (2031 palabras) Publicado: 29 de noviembre de 2010

Lucia Pozuelo Alarcón

To start we have to know about what is LIA.
From 1250 to 1850 a big part of the world experimented a lowering in the temperatures. The average in the temperatures was about 1-1.5 degree Celsius cooler than today. It´s thought that this could be becausethere were less solar activity and more erupting volcanoes.
This had a major impact in Europe. It can be seen in the tree ring data which show a minimum growth during these centuries, and also appeared diseases due to moisture.
But we can´t say that this Little Ice Age was a real Ice Age because it didn´t cold enough to cause ice sheets grow large.

Archipelago Svalbard is situated inGlacial Artic Ocean. Also known as Svalbard or Spitsbergen, are an archipelago in the Arctic Ocean north of Europe, part of the Kingdom of Norway. Is a group of islands ranging from 74 degrees to 81 degrees north and 10 º to 35 º east, forming the northernmost part of Norway. Only three of the islands are populated: Spitsbergen, Bjørnøya and Hopen. The largest settlement is Longyearbyen

Artic sea iceis an important factor in the global climate system, mainly because this ice cools the planet by reflecting the light of the sun back into space. This ice is created when the accumulation of years of snow that had fallen into the winter months, however, did not melt in the summer. 
As more and more layers are deposited, the snow is compressed, it transforms into ice, and more compact and moredensely populated with each passing year. On the other hand it also helps the ocean circulation as it turns the warm Pacific waters that go to the Artic in cold water and more salad. Also the sea ice also shapes the Artic, for example it defines the organisms that make up the ecosystem. But this ice is not stop. To a depth of 18 meters, the ice begins to move as a result of its own weight andgravity. An increase in snow and ice reflects more solar energy, making it even colder surface temperature. the amount of snow and ice can be increased or decreased due to small changes in temperature due, for example, small changes in solar radiation and volcanism, surface albedo can be a resonator for a more intense reduction surface temperature.
This fact becomes very important with a mass of airover the Atlantic and
low atmospheric water will diverge towards the edge of the Atlantic basin, while a high atmosphere will cause the streams that converge toward the center. It is well known that this is the diverging trends in the North Atlantic that keeps the Gulf Stream power and if an atmosphere of high to replace the usual lower atmosphere over the North Atlantic, the currents converge,weakening Gulf Stream greatly.

The extension of the ice has decreased in the last thirty years. The weather can be different each year and makes that some winters more ice be produce than others. In this 30 years, average temperatures has risen because of in winter is formed less ice than it must be formed and in summer it defrosts faster. If this last happens, the temperatures are higher and thesolar radiation won´t be reflected into space and ocean will absorb it augmenting the temperature of the ocean. So when winter comes, it will be more difficult for ice to form.

In Svaldbard have been superimposed layers of ice over the past one hundred thousand years but sub-glacial deposits are quite thin and mainly restricted to areas below the marine boundary. Moraine ridges at the mouths ofvalleys, fjords and submarine shelf-crossing troughs demonstrate that the larger glacial pathways were occupied by grounded, warm-based ice during the last glaciation.

Evolution of the Artic in the last millennium

In this graph we have two reconstructions. The black line covers the period 1200-1997, is related to the North Atlantic area and comes from the combination of paleoclimatic...
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