The Shrub's pet anti-Kyoto "scientists" have produced findings attacking the idea of global warming. This SciAm article shows the flaws in their "methodology."
"Their analysis doesn't consider whether the warm/cold periods occurred at the same time," says Peter Stott, a climate scientist at the U.K.'s Hadley Center for Climate Prediction and Research in Bracknell. For example, if a proxy record indicated that a drier condition existed in one part of the world from 800 to 850, it would be counted as equal evidence for a Medieval Warming Period as a different proxy record that showed wetter conditions in another part of the world from 1250 to 1300. Regional conditions do not necessarily mirror the global average, Stott notes: "Iceland and Greenland had their warmest periods in the 1930s, whereas the warmest for the globe was the 1990s."
Soon and Baliunas also take issue with the IPCC by contending that the 20th century saw no unique patterns: they found few climatic anomalies in the proxy records. But they looked for 50-year-long anomalies; the last century's warming, the IPCC concludes, occurred in two periods of about 30 years each (with cooling in between). The warmest period occurred in the late 20th century–too short to meet Soon and Baliunas's selected requirement. The two researchers also discount thermometer readings and "give great weight to the paleo data for which the uncertainties are much greater," Stott says.
(Thanks, David!)
