Climate change sceptics lose vital argument says the New Scientist. This is a novel twist on a paper in Nature: Gulf Stream density structure and transport during the past millennium; David C. Lund, Jean Lynch-Stieglitz and William B. Curry; doi:10.1038/nature05277. The editor says of it: an analysis of sediment cores from the Florida Straits, where the Gulf Stream enters the North Atlantic, has been used to reconstruct a record of the past 1,000 years. The results suggest that the Gulf Stream was weakened during the Little Ice Age (AD 1200-1850), a time of unusually cold conditions in the North Atlantic region, particularly Europe, implying that changes in Atlantic Ocean circulation had an impact on climate during historical times.
NS asserts that this may explain why MBH (aka the Hockey Stick) doesn’t show the Little Ice Age, since it makes it a regional phenomenon. Um? the cooling that resulted was confined mainly to the northern hemisphere, says Lynch-Stieglitz – which indicates it was a regional effect. Michael Mann at Pennsylvania State University in University Park, who constructed the hockey stick graph, has always argued that if this were so, the little ice age would not show up on a global temperature record. This is odd: MBH has only for the NH anyway… The idea that the LIA was regional and/or more of a redistribution is a standard one; its not really clear how this result adds anything to it. I suspect this is NS getting somewhat carried away.