glacial+melt

Welcome to the PASB page discussing glacial melt as a part of global climate changes! Click here to go the page on sea level rise.

Concern for glacial melt is growing, as the glaciers themselves are shrinking. This is because the melting of the world´s glaciers is one of the main reasons that the world sea level is expected to rise throughout the coming century.

According to the [|world glacier monitoring service], glaciers cover approximately 160 000 square kilometers of the earth´s surface. This cover is mainly distributed throughout the major mountain ranges of the globe. A glacier is an immense field or stream of ice, formed in areas of perpetual cold and shaped by the topography in that area, as a result of the accumulation of precipitation. A differentiation is made between glaciers and ice caps, as ice caps are considered not to be restricted by topography and allowed to spread without land getting in the way. Ice caps actually cover about four times as much area as glaciers do worldwide.

Glaciers form over long periods of time, as snow accumulates in mountain ranges. Over time, the pressure of increasing amounts of snow will cause the snow to turn to ice. The pressure at the bottom of the glacier forces the air from out of the ice, and also causes the ice to become very flexible. For this reason, glacier ice will actually flow downward.

The United Nations Environment Programme uses the research of the world´s leading glaciologists and environmental scientists in its report from 2010: []. In the report, the link between the loss of large glaciers in the last 30 years and the rise of global average temperatures is clearly emphasized. One dramatic example of this is the retreat of the Morteratsch Glacier from 1985 and 2007.

[] Explain how environmental conditions (temperature and precipitation) impact glacial mass budget; identify where snow accumulates in a glacier and justify why. •Explain how ice moves within a glacier; describe and illustrate flow within a glacier. •Explain or illustrate (demonstrate) how glaciers (i) stay at equilibrium, (ii) grow/advance, (iii) shrink/retreat, and (iv) form; compare climatic conditions leading to each. •Determine and illustrate how multiple advance-retreat cycles affect the record of glacial end moraines.
 * Glacier Simulation:**


 * List of key terms:**

moraine - the general term for debris of all sorts originally transported by [|glaciers] or ice sheets that have since melted away (WordIQ.com)

ice cap - An extensive dome-shaped or platelike perennial cover of ice and snow that spreads out from a center and covers a large area, especially of land (thefreedictionary.com) thermal expansion (oceans) - as the molecules of water in the ocean are gradually heated, they move further apart, increasing the volume of the ocean water. cryosphere - the places on the earth´s surface where water exists as a solid. Sheepbacks - Glacier movement can create these asymmetrical rock formations and hills. The glacier wears down the rocks gradually, forming one smooth, sloped side, but pulls r­ocks away from the other side as it passes over, forming a sharper, more jagged slope. These formations can be used to determine the direction of glacier movement. People once thought these looked like the backs of sheep, so they called them //roche moutonnée//, which is French for "sheep back." ([|www.howstuffworks.com])

[] The link above refers to the glacial melt in the Peruvian Andes. As the rate of melting of glaciers increases, the drinking water in dry countries such as Peru is endangered. Check it out!
 * Current Event:**

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