Overplaying the Human Contribution to Recent Weather Extremes

This a post by Patrick J. Michaels of Cato. Click here to read it. Excerpt:

"Where to start? How about last summer’s Russian heat wave?

The Russian heat wave (and to some degree the floods in Pakistan) have been linked to the same large-scale, stationary weather system, called an atmospheric “blocking” pattern. When the atmosphere is “blocked” it means that it stays in the same configuration for period of several weeks (or more) and keeps delivering the same weather to the same area for what can seem like an eternity to people in the way. Capitalizing on the misery in Russia and Pakistan, atmospheric blocking was added to the list of things that were supposed to be “consistent with” anthropogenically stimulated global warming which already, of course included heat waves and floods. And thus the Great Russian Heat Wave of 2010 became part of global warming lore.

But then a funny thing happened – scientists with a working knowledge of atmospheric dynamics started to review the situation and found scant evidence for global warming.

The first chink in the armor came back in the fall of 2010, when scientists from the Physical Sciences Division (PSD) of the Earth System Research Laboratory (ESRL) of the National Oceanic and Atmospheric Administration (NOAA) presented the results of their preliminary investigation on the web , and concluded that “[d]espite this strong evidence for a warming planet, greenhouse gas forcing fails to explain the 2010 heat wave over western Russia. The natural process of atmospheric blocking, and the climate impacts induced by such blocking, are the principal cause for this heat wave.”

The PSD folks have now followed this up with a new peer-reviewed article in the journal Geophysical Research Letters that rejects the global warming explanation. The paper is titled “Was There a Basis for Anticipating the 2010 Russian Heat Wave?” Turns out that there wasn’t.

To prove this, the research team, led by PSD’s Randall Dole, first reviewed the observed temperature history of the region affected by the heat wave (western Russia, Belarus, the Ukraine, and the Baltic nations). To start, they looked at the recent antecedent conditions: “Despite record warm globally-averaged surface temperatures over the first six months of 2010, Moscow experienced an unusually cold winter and a relatively mild but variable spring, providing no hint of the record heat yet to come.” Nothing there.

Then they looked at the long-term temperature record: “The July surface temperatures for the region impacted by the 2010 Russian heat wave shows no significant warming trend over the prior 130-year period from 1880 to 2009…. A linear trend calculation yields a total temperature change over the 130 years of -0.1°C (with a range of 0 to -0.4°C over the four data sets [they examined]).” There’s not a hint of a build-up to a big heat wave.

And as to the behavior of temperature extremes: “There is also no clear indication of a trend toward increasing warm extremes. The prior 10 warmest Julys are distributed across the entire period and exhibit only modest clustering earlier in this decade, in the 1980s and in the 1930s…. This behavior differs substantially from globally averaged annual temperatures, for which eleven of the last twelve years ending in 2006 rank among the twelve warmest years in the instrumental record since 1850….”

With regard any indication that “global” warming was pushing temperatures higher in Russia and thus helped to fuel the extreme heat last summer, Dole et al. say this: “With no significant long-term trend in western Russia July surface temperatures detected over the period 1880-2009, mean regional temperature changes are thus very unlikely to have contributed substantially to the magnitude of the 2010 Russian heat wave.”"