Inconvenient "truths" about global warming - The Boston Globe

I came [to Venice] for Mikhail Gorbachev's World Political Forum conference on how the press is handling global warming. The good news is that climate change coverage has increased in recent years faster than global temperatures.
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The irony for Europe is that climate change could result in colder, not warmer, temperatures. Northern Europe, on a parallel with Canada's Hudson Bay, enjoys its milder climate because of the Gulf Stream funneling heated water north. But in order to work, the Gulf Stream waters must be allowed to sink when they reach the cold waters of the north and make their way back south again along the ocean floor. Scientists at the Woods Hole Oceanographic Institution call this the "conveyor belt."

Should the waters from the Arctic become less cold, and less salty due to melting ice, as is now happening at a rapid rate, the Gulf Stream waters might not be able to sink as readily, thus breaking up the current, and bringing a colder climate to Northern Europe and North America. This has happened before. From the 16th century until the middle of the 19th century, Europe experienced markedly colder temperatures - as witnessed by paintings of people skating on the canals of Holland, which seldom happens today. And the famous painting of George Washington crossing the Delaware shows ice on the river at levels no longer seen.

The problem is all the more complicated in that man-made greenhouse gases are riding on the back of a normal warming trend following a 200-year cold snap.