The Link Between Global Warming and Erosion

rockfall-jj-01.gifMike Dunford over at ScienceBlogs explains why global warming can speed up erosion in some cases (f.ex., according to the Guardian, about two million cubic meters of Mt. Eiger in the Swiss Alps are expected to go down): "A major cause of erosion in areas where there are cold winters is the freeze-thaw cycle. Water is pretty good at getting into cracks in rock, and other such confined places. Water also, as you are probably aware, expands when it freezes. When water freezes in cracks in the rock, it acts like a wedge, forcing the cracks wider. When the ice melts, the crack can hold more water, and the next time it freezes, the water will expand again and force the crack wider still. Given enough time, and enough freeze-thaw cycles, rock will break as a result. [...] Now for the global warming tie-in. As temperatures rise, there are going to be places that see more freeze-thaw cycles per year than they did in the past. [...] an increase in warming that results in temperatures climbing over the freezing point ten or twelve times in a year, instead of the three or four that was common in the past, really isn't much of a change. In terms of the number of freeze-thaw cycles, it's an enormous increase." Read the whole thing and more at: ::Global Warming and Rockfalls

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