Contrarians are rubbishing any claims of a connection, but they are using a Straw Man Fallacy, saying that environmentalists are claiming that global warming CAUSED Sandy.
Anthropogenic Global Warming did not cause Sandy. Hurricanes, even in October, are part of the weather scenery in the USA, and have been so well before before our influence on climate became apparent.
However, it is perfectly reasonable to claim that global warming affected the path and intensity of Sandy.
It is always necessary to put events into the fullest possible context.
Climate warming theory predicts that the numbers of hurricanes may decrease, but that the intensity of hurricanes will increase. (IPCC 2007)
The records bear this out:
|Source Dr Ryan N Maue|
Here is the global temperature, just for comparison:
Here is another graph, again from Dr Maue:
And in case anyone wants to say "Well it's all due to natural variation of ocean currents", the ocean generally is getting warmer, and you can gain a visual impression of this from the ENSO charts, with more red warm spikes showing in the more recent records:
I did a plot from some original data for the ENSO and it showed an upward trend, but unfortunately I lost the link between the graph and the source, so I cannot show it.
The increasing frequency of positive phases of the oscillations is to be expected given the increase in total ocean heat content:
Global warming is taking place in the Arctic much faster than it is taking place globally. This has caused a blocking high pressure event, which causes the jet stream to wander further south, which has caused the hot USA and cold UK summer. This block caused Sandy to veer coastwards.
In conclusion - it is safe to say that Sandy was not caused by was exacerbated by Man-made Global Warming.