Posted by Peter Ceresole on March 11, 2006 at 21:59:41 from 80.177.22.49 user PeterC.
In Reply to: Why not? (was Will Coniston/Windemere freeze?) posted by Lyn on March 11, 2006 at 20:42:57:
what were the conditions, which caused the lake(s) to freeze previously, that would not reoccur now?
Cold winters? It takes a good period of sustained cold to freeze a lake the size of Windermere. Britain being an island, it's warmed in winter (and cooled in summer) by the thermal inertia of the ocean around it. Even the North doesn't get the cold winters that say Germany or the USA experience at similar latitudes. Plus there's the Gulf Stream. Surface water of the ocean is warmed by sun and blown by prevailing westerlies towards Britain. I was once told that 30% of the solar energy falling on the whole of the Atlantic was delivered to the coasts around Britain. That's a huge amount of heat and the result is that Britain sits in a Turkish bath.
Previously, over all temperatures meant that despite this the lake would freeze from time to time. But global warming is a reality- I've seen the effects very clearly in my lifetime- and for that reason the Lake is unlikely to freeze again in a hurry.
However, there's a paradox; global warming is changing the circulation patterns in the North Atlantic. The last time there was a warmer, high CO2 world, ocean floor mud cores show that the Gulf stream switched off, and very rapidly. Direct observations seem to confirm that this is happening again, now. If so, Windermere may yet revert to freezing in winter and having 'Pigeon Post' summers every year.
In case anybody would like a look at what happens to a central European lake rather bigger than Windermere....