It is important to mention that these processes are not
uniform over the global ocean and thus the disequilibrium is not only between ocean and atmosphere, but there are also differences in radiocarbon levels within the ocean.
By examining the spatial pattern of both types of climate variation, the scientists found that the anthropogenic
global warming signal was relatively spatially
uniform over the tropical
oceans and thus would not have a large effect on the atmospheric circulation, whereas the PDO shift in the 1990s consisted of warming in the tropical west Pacific and cooling in the subtropical and east tropical Pacific, which would enhance the existing sea surface temperature difference and thus intensify the circulation.