It is not only American climate scientists who are guilty of bias in their research and reporting, this comes from "down under", Australia.
Ignoring a Natural Event to Blame Humans
By ignoring a natural event scientists blame climate changes on human activity
In the last week of September 2007 we had yet another example of a well-recognized natural climate event being ignored in order to sell the notion that mankind is responsible for global warming. Maybe it was deliberate or maybe just ignorance, but you'd think that capable scientists would look closely at prior research and the data and not just be activists for their latest cause.
This time it was Power and Smith, from Australia's CSIRO and Bureau of Meteorology respectively, who were reporting a weakened Walker Circulation over the last 30 years and a concurrent period of unprecedented El Niño dominance [note 1], both of which they blamed on human activity.
Last year in May it was Vecchi et al  who told us that the same Walker Circulation had weakened by 3.5% since the mid-1800s and there that there was a just 1% probability that this was due to natural events. Vecchi and Soden  recently continued their line of argument from 2006 by claiming that an ensemble of 23 climate models confirms that weakening of the Walker Circulation is to be expected under anthropogenic warming.
These three papers seem to be the product of researchers lost in their computer simulations and putting the virtual reality of computer models ahead of observational reality.
What they attribute to human activity are natural events that have been well described by other researchers.
The Walker Circulation
The Walker Circulation, to which all three papers refer, is a large zonal circulation cell over the equatorial Pacific. Air in the extreme western Pacific rises from near sea level to around 15,000 feet, then travels eastward under the Earth's rotation to the eastern Pacific where it sinks back to sea level and westerly winds force it back across the ocean to the complete the loop.
Figure 1 - Walker Circulation during normal conditions compared to that during El Nino conditions
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