The Inconvenient Skeptic did an interesting analysis of the the UAH temperature data: Temperature trends by latitude. Instead of looking at the grand, global picture, he looked at temperatures by region: Northern, Tropics and Southern.
As it turns out, only the Northern third of the globe saw a warming trend from 1979 to 1998. Neither the Tropics not the Southern third showed much of a warming trend in that same period. In the period between 1998 and 2011 none of the regions showed a trend, leading the Inconvenient Skeptic to comment:
These results are very bad for the global warming crowd. One of the key claims is that the whole Earth is warming up and that in the past there was only regional variations in climate. That is a key attribute to dismissing things like the Little Ice Age and the Medieval Warming Period.
The modern data is showing that the warming is regional and not steady and certainly not increasing. 1998 really seems like a significant transition year as well. The enormously powerful El Nino that year drove the Tropical temperature anomaly up over 1 °C for 4 months. That is by far the largest anomaly for large regions of the Earth in the data. That corresponds to the change in temperature in the Northern region.
And thus it turns out that ‘Global Warming’ is not so global, after all. And with that the whole AGW theory, which hypothesizes a truly global trend, caused by human-produced CO2, is shown to be … errrm… incomplete. Wrong. False.
We knew this, of course. But it is gratifying to be hammering yet one more of a series of final nails in the coffin.