More Alarmist Nonsense About Glaciers
By Paul Homewood http://m.dailykos.com/story/2015/03/31/1373930/-Massive-Glacier-Melt-and-Fresh-Water-are-Pouring-into-the-Gulf-of-Alaska?detail=email More from the “We’re all going to die, and its all YOUR fault” Department! The Daily KOS are concerned about Alaskan glaciers: The world is changing before our very eyes yet most of us choose to ignore it. There has been a lot of horrible news lately regarding the rapid melting of the planets snow and ice. Irreversible melt in Antarctica, ice free arctic ocean in summer, and massive ice shelves that have held back Antarctica’s glaciers for tens of thousands of years are now cracking. In Alaska, land based melting glaciers are rapidly retreating under the pressure of their own weight and the forces of gravity. The National Snow and Ice Data Center explains how a glacier moves. “Glaciers move by internal deformation of the ice, and by sliding over the rocks and sediments at the base. Internal deformation occurs when the weight and mass of a glacier causes it to spread out due to gravity. Sliding occurs when the glacier slides on a thin layer of water at the bottom of the glacier. This water may come from glacial melting due to the pressure of the overlying ice or from water that has worked its way through cracks in the glacier. Glaciers can also readily slide on a soft sediment bed that has some water in it. This is known as basal sliding and may account for most of the movement of thin, cold glaciers on steep slopes or only 10 to 20 percent of the movement of warm, thick glaciers lying on gentle slopes. When a glacier moves rapidly around a rock outcrop or over a steep area in the bedrock, internal stresses build up in the ice. These stresses can cause cracks, or crevasses, on the glacier surface.” Alaska’s southern coast glaciers that once terminated in the ocean, have now retreated far up Alaska’s valleys. A recent study shows that fresh water and glacial melt from these retreating glaciers are “pouring into the Gulf of Alaska accumulating more water than is seen in some of the world’s great rivers”. The Oregon State study reports the tragic news. Incessant mountain rain, snow and melting glaciers in a comparatively small region of land that hugs the southern Alaska coast and empties fresh water into the Gulf of Alaska would create the sixth largest coastal river in the world if it emerged as a single stream, a recent study shows. Since it’s broken into literally thousands of small drainages pouring off mountains that rise quickly from sea level over a short distance, the totality of this runoff has received less attention, scientists say. But research that’s more precise than ever before is making clear the magnitude and importance of the runoff, which can affect everything from marine life to global sea level. The collective fresh water discharge of this region is more than four times greater than the mighty Yukon River of Alaska and Canada, and half again as much as the Mississippi River, which drains all or part of 31 states and a land mass more than six times as large. “Freshwater runoff of this magnitude can influence marine biology, nearshore oceanographic studies of temperature and salinity, ocean currents, sea level and other issues,” said David Hill, lead author of the research and an associate professor in the College of Engineering at Oregon State University. “This is an area of considerable interest, with its many retreating glaciers,” Hill added, “and with this data as a baseline we’ll now be able to better monitor how it changes in the future.” Note: Some of the links above I added, they are not all part of the original OSU article This is one of the first studies to accurately document the amount of water being contributed by melting glaciers, which add about 57 cubic kilometers of water a year to the estimated 792 cubic kilometers produced by annual precipitation in this region. The combination of glacial melt and precipitation produce an amount of water that’s larger than many of the world’s great rivers, such as the Ganges, Nile, Volga, Niger, Columbia, Danube or Yellow River. My first reaction, on a simplistic level, is that this is exactly what glaciers do, in other words melt. If they did not, snow and ice would accumulate and we would end up with sea levels hundreds of feet lower, and another ice age. On a deeper level, however, the article is grossly misleading for what it omits to tell you. 1) Glaciers have been advancing since the 18thC Glaciologists are absolutely clear that Alaskan glaciers have been receding since the late 18thC, as the Earth began to claw its way out of the Little Ice Age. For instance, the USGS have put together this map of how the Glacier Bay glaciers have gradually retreated. The vast majority of the glacial retreat was in the 19thC, long before SUV emissions. https://notalotofpeopleknowthat.wordpress.com/2014/05/21/lying-accelerates-at-the-nyt/ The USGS add: The glacier that filled Glacier Bay during the Little Ice Age began its retreat from the mouth of the bay more than 200 years ago and has exposed a magnificent fjord system about 100 km long. The massive glacier retreated past Sitakaday Narrows ~190 years ago, retreated past Whidbey Passage ~160 years ago, and reached the upper end of the main bay by 1860 (~140 years ago). They also conveniently have a photographic record of the Muir Glacier, comparing the ice extent in 1941, 1951 and 2004. Clearly, much of the retreat took place between 1941 and 1951. (The USGS state that it retreated by 3km between 1941 and 1950, and 4km since). 1941 1951 2) Little Ice Age The science is absolutely clear that there was a massive, worldwide expansion in glaciers during the Little Ice Age. In Alaska, there is evidence of three separate glacial advances, in the 12th/13thC, 17th/18thC, and finally in the late 19thC. Study of the Prince William Sound, Alaska, show that Ice margins were generally close to the late LIA maximum position at the time of the first visits of scientific parties around the turn of the century [around 1900]. There is also plenty of evidence of a similar massive expansion of glaciers from Europe, Iceland, South America and New Zealand during the Little Ice Age. Studies of glaciers in Greenland and Iceland show that, in the 19thC, they reached their maximum extent since the ice age. 3) Medieval Warming How do today’s glaciers compare to how they looked before the Little Ice Age set in? There is physical evidence from Alaska that glaciers were smaller back in the Middle Ages than they are now. As glaciers have been receding in recent years, remains of forest, carbon dated back to the Middle Ages, are being uncovered. These have been found at the Exit, Mendenhall and Ultramarine glaciers. At the Mendenhall, some tree remains have been dated back to 2000 years ago (the Roman Warming Period). We find similar discoveries in Patagonian glaciers. In all these cases, the glaciers must have terminated well uphill of the trees, which could not possibly have grown at the very edge of the ice, where they are situated now. It also seems extremely unlikely that there are not more trees to be found further up stream. In short, there is nothing to suggest that recent retreat of glaciers is anything other than a natural phenomenon, or that their current size is unprecedented or unusual.
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