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Why Glaciers and Polar Ice are Melting Faster






     The International Panel on Climate Change (IPCC) is the agency that gives us scientifically approved and governmentally sanctioned views of complex issues relating to climate change.

Its view on ice melting has been especially cautious. The panel report predicts that ice on glaciers on mountains and in Polar ice sheets is melting and is going to raise levels of world oceans by 7 to 23 inches by 2100. Sea level rise has two major components; water expands when being heated and water from melting ice on lands flows to the oceans and raises their levels. Exact measurements of sea levels are extremely difficult. Atmospheric pressure, Earth movement, global wind patterns, and ocean currents affect readings.

We all have read that mountain glaciers are receding or disappearing, we have read that the Polar Bears are threatened, and we may have read that snow making equipment is now used in skiing areas.

The culprit for what is happening to glaciers and Polar ice sheets is global warming. However, the fast acceleration of ice melting during the last few decades can not be explained fully by rising global temperatures.

A specialty in engineering science deals with the prediction of heat and mass transfer in industry. It is a discipline that is shunned by many engineering students. Heat transfer courses deal with three quite different modes of heat transport. Heat is transferred by conduction, by convection, and by radiation. If you have ever burned a finger by touching a hot surface you are aware of these three modes. If you touch a hot surface you feel pain almost immediately. Heat is conducted to your finger and the nerves in your finger report pain to protect you. If you hold your finger under the faucet and cool it with cold water, your finger is being cooled by a moving liquid and you feel the effects of convection. You can feel radiation, when sitting in front of a burning fireplace.

All three processes take place when ice is melting. During summer, warmer winds strike ice surfaces and heat the surface. First the snow cover is melted. Only after the snow cover has melted completely, can the ice be heated. During the day the ice surface my get wet, during night the melted water on top freezes again. Why are these processes important?

When winds blow over a snow or ice surface, the warmer air transfers heat to it. In the process the air cools down and looses its ability to heat. Only warm air can transfer heat and melt snow or ice. After giving off its heat and lowering its temperature, the blowing air has lost its excess energy. If only air temperatures were responsible for ice melting, we would experience snow and ice melting rates that would be only marginally higher than those 100 years ago and melting of ice deposits would not be threatening, yet.

Radiation heat transfer from surface winds is the one variable that has changed dramatically during the last century. Air now contains one third more carbon dioxide and other greenhouse gases. Greenhouse gases are optically active, they emit heat by radiation. Therefore, the air that is blowing over ice surfaces has increased its radiating power by a third, too. This is why ice melting is accelerating.

There is an additional, more insidious reason. When thermal radiation hits the surface of a snow blanket, it melts only the surface of the snow. When thermal radiation hits the surface of wet ice, another process takes over. Thermal radiation is able to enter the ice itself and will penetrate deeply if the ice is clean. Dirty ice absorbs heat within a shorter distance. The ice is heated from the inside! Worse, the heat inside the ice mass cannot get out anymore. During summer, the ice is heated from within. During winter, when the ice is covered by a snow blanket, the heat cannot escape. Instead, it penetrates the entire ice mass by conduction.

The next summer, after the snow on top has melted, the ice continues to soak up heat again. The amount of heat each year is small but continues to accumulate for years and decades. Shortly before melting, the ice looses mechanical strength rapidly and becomes prone to throw off large pieces on its outer periphery. Sometimes another phenomenon can be observed. If the ice sits atop a layer of mud or silt, the mud looses strength at the same time when the ice is weakening. The melting mud serves as a lubricant and may let the ice sheet move downhill.

Can we do anything to reverse these threatening processes? Realistically, nothing. Reversing atmospheric greenhouse gas concentrations would be effective. While it is conceptually possible, it will take more than fifty years before we can expect to begin using large scale greenhouse gas removal technology. Otherwise, we can protect bare ice with a snow or dirt blanket. Right now, there seem to be no other alternatives.

Obviously, the described processes are not part of the models that forecast ice melting and sea level rises. Therefore, the world must prepare itself for an ugly surprise. Sea levels will rise much faster than the IPCC has been predicting. Prudent governments will prepare for rises that are twice as high as predicted by the IPCC in the year 2100.




Article Source: http://www.abcarticledirectory.com


Dr. Hemsath recently published the book: CLIMATE CHANGE - GOLD RUSH OR DISASTER? For 50 years he has worked as scientist, process engineer, Corporate Vice President of R&D;, Company President, CEO, and Inventor. He holds more than 60 US Patents. He is working on a new book: "THE SOLUTION FOR ENDING GLOBAL WARMING AND CLIMATE CHANGE". Go to www.thermalexpert.com


Posted on 2008-09-17, By: *

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