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Lefty Mark's avatar

Sea levels are rising and threatening island nations due to AGW; this is definitely true. Causes of flooding in NW Europe are more complex though. One of the factors is ongoing isostatic adjustment of the lithosphere following the retreat of the ice sheets from the most recent ice age glaciation. For instance, southern England continues to experience massive flooding because it is actually sinking in elevation while the northern part of the island, Scotland, is rising in elevation. During the last glaciation Scotland was buried under something like 1000 feet of ice. The weight of all of that ice compressed the Earth's crust in the Northern hemisphere, pushing it down into the mantle (asthenosphere). This action pushed part of the relatively elastic mantle outward away from the area of compression. The migrated mantle then pushed up the crustal surface that overlayed it. In the case of Great Britain the ice-free southern half of the island rose up as the ice sheet compressed the northern half. Over the millennia since the ice sheet retreated the displaced mantle has been gradually migrating back under the now uncovered regions, causing those areas to rise back up in elevation and causing the areas that it had been previously pushed into to sink back down. This is what is happening in Great Britain and other parts of northwestern Europe. Local increases in sea level due to thermal expansion of the hydrosphere are compounding the effect and adding to the problem.

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Lefty Mark's avatar

But who has the gall to de-liver the bad news?

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