Natural, large-scale climate patterns like the PDO and El Niño-La Niña are superimposed on global warming caused by increasing concentrations of greenhouse gases and landscape changes like deforestation. According to Josh Willis, JPL oceanographer and climate scientist, “These natural climate phenomena can sometimes hide global warming caused by human activities. Or they can have the opposite effect of accentuating it.” http://earthobservatory.nasa.gov/IOTD/view.php?id=8703
It is difficult to imagine that climate is at all predictable against a backdrop of vigorous natural variability – and it is not as if the rate of warming is all that striking. I am inclined to take the high point of the early century warming – 1944 – as a starting point and the late century high point – 1998 – as the finish. This accounts for both a multi-decadal cooling and warming period. Surely – there is an obvious rationale there. We may even assume that all of the warming between 1994 and 1998 was anthropogenic – unlikely as that is – to give a warming rate of 0.07 C/decade. Well short of 2 degrees C anytime soon – especially as the oceans are contributing to surface cooling for decades seemingly.
I am inclined to just move on entirely. There are plenty of things to be getting on with. Trade, development, progress and conservation.