| Summary: | Eastern boundary upwelling ecosystems: integrative and comparative approaches, 2-6 June 2008, Las Palmas, Gran Canaria, Spain It has been proposed that coastal upwelling in the four major eastern boundary current systems will be intensified as a consequence of global warming. Recent research has suggested a significant increase of upwelling intensity off Northwest Africa. Evidence is based largely on the derivation of proxy sea surface temperatures from isotope analysis of two sediment cores recovered off Cape Ghir, Morocco. An accelerating decrease in excess of 1ºC over the last century was concluded for near surface temperature near the Cape. Support for this conclusion was found in an increase in Bakun's upwelling index for the latitude of the Cape. We examine the evidence for a general intensification of upwelling within the whole Canary current upwelling system. Using measured wind data from the WMO meteorological station network, we find no evidence of a coherent wind intensification at the scale off Northwest Africa. We find that Bakun’s pressure derived upwelling index, calculated most reliably over the last 50 years, indicates a decrease in upwelling strength at all latitudes from 15º to 43ºN in the North Atlantic Upwelling region, except in the vicinity of Cape Ghir. Surface temperature records from ships-of-opportunity since 1956 (COADS data set) and also from the Reynolds et al. combined satellite-in situ data set starting in 1981 show a significant and correlated increase at all latitudes in the region, including in the area around Cape Ghir. Moreover, sea surface temperatures measured at points on the Portuguese coast since 1960 also show a significant warming. We conclude that in general upwelling intensity off Northwest Africa is decreasing and that any intensification off Cape Ghir must be explained by localized processes No
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