Tuesday, October 25, 2011

Global Warming Settled?

Global Warming is finally settled science. At least that's what Eugene Robinson says.

For the clueless or cynical diehards who deny global warming, it's getting awfully cold out there.

The latest icy blast of reality comes from an eminent scientist whom the climate-change skeptics once lauded as one of their own. Richard Muller, a respected physicist at the University of California, Berkeley, used to dismiss alarmist climate research as being "polluted by political and activist frenzy." Frustrated at what he considered shoddy science, Muller launched his own comprehensive study to set the record straight. Instead, the record set him straight.

[...] The Berkeley group's research even confirms the infamous "hockey stick" graph — showing a sharp recent temperature rise — that Muller once snarkily called "the poster child of the global warming community." Muller's new graph isn't just similar, it's identical.

What Muller and the Berkeley Group did was to examine the data from as many weather stations as possible. They found that 2/3s of them show significant warming while only 1/3 show cooling. They parsed the data different ways, limiting themselves to weather stations classified as good, ones classified as bad, ones in rural areas, ones in urban areas. Their results consistently showed warming (except on those 33% that showed cooling).

So, is the argument over? It is for Robinson who wants to use this study to bash Republicans. For the rest of us, there are still many issues.

While it is represented as matching the IPCC's data, the Berkeley data does not. It shows two degrees of warming where the IPCC only found .5 degree. Muller dismisses this as inconsequential. His team did not study ocean temperatures and he is sure that is where the

The study seems to be presented in such a way as to emphasize the warming. It talks about warming since the 1950s but their own chart shows nearly a full degree difference between the 1930s and the 1950s. By starting at a low point, the amount of warming shown is exaggerated.

Robinson is wrong when he says that this confirms the Hockey stick. Again, Berkeley's charts show highs were within historic levels through 1980. Berkeley's charts begin at 1800 (with the invention of the thermometer) while the Hockey Stick was an attempt to chart historic temperatures going back 1,000 years. That extra 800 years is important since it contains a historic warm period. Without knowing how warm it was without the effects of carbon dioxide we have no way of evaluating current temperatures.

Muller does not mention the Hockey Stick in his column nor does the Berkeley web site mention it. Robinson got that reference from a Green blogger at the New York Times. If you look at Berkeley's chart and the Hockey Stick from 1800 on, you find that the two do not match very well.

The biggest issue is that the Berkeley study was limited to examining temperature readings. It did not assess theories about its cause or the limits to warming. Even the IPCC admitted that some of the warming was caused by the sun and other natural sources. That is why estimates of early temperatures are so important and so contentious. Physics say that there is a limit on the amount of hat that CO2 can trap. Global warming theory says that by the time we reach that limit, enough additional water vapor will be in the atmosphere to cause additional warming. Since this part is entirely theoretical, it is also contentious.

The Berkeley data also confirms that warming has slowed or stopped over the last few years. This is too small a period to make projections from, but so is 60 years.

The well-informed skeptic does not deny that warming has happened over the last two centuries. Prior to the Greenhouse theory orthodox climatology said that there was a Medieval warm period followed by a cold period known as the Little Ice Age which ended in the 19th century. The skeptic says that the warming since then is mainly the start of a natural warm period. Muller and his team have published nothing that confirms or disproves this.

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