August 19, 2010

The Great Russian Heat Wave of 2010 Part II

Filed under: Health Effects, Heat Waves

Last week we presented our analysis of the causes behind this summer’s record-breaking heat wave in western Russia.

We summarized the situation thus:

But global warming theory doesn’t come anywhere close to explaining why it’s so darn hot this summer in Moscow.

Long-term observations suggest a more basic cause—an unusual and unprecedented (at least since 1950) confluence of several naturally-occurring atmospheric circulation patterns that together combined to set the stage for extreme warmth. Add to that urbanization, changing forestry practices, and perhaps throw in a dash of global warming for good measure, and you take a situation that would otherwise be “very hot” and up it a notch to “record hot.”

Since then, another analysis has been released that concludes the same thing—actually, the new analysis is even less sympathetic to assigning any blame to global warming than even we were.

And surprise, surprise, the analysis wasn’t from some alleged fossil-fuels backed professional denialist group, but from the folks at the Physical Sciences Division (PSD) of the Earth System Research Laboratory (ESRL) of the National Oceanic and Atmospheric Administration (NOAA) of the Department of Commerce of the United States Government. These are folks who live and breathe atmospheric dynamics.

The PSD describe their findings in the report the “The Russian Heat Wave of 2010”, which is filled with interesting analyses and graphics and worthy of a full read.

Here, we excerpt a few things of particular interest. First, the PSD lays out the situation (emphasis added):

What is the historical context for the July heat wave over western Russia? During the period 1880-2009, the region’s monthly July surface temperatures have experienced several very warm years of about +3°C departures (1931 , 1955, 1981, 1988, and 2002), and comparably cold Julys having about -3°C departure (1950, 1957, 1968, 1976, and 1994). Warm Julys alternating with cold Julys describes the typical sequence of events over western Russia during the last 130 years, with little or no discernible trend in July temperatures since 1880. Yet, the July 2010 anomalies averaged over western Russia will exceed the warmest Julys on record, and such an extreme event demands an explanation.


Figure: Time series of July near surface temperature anomalies averaged over the area 50-60N and 35-55E. Anomalies are calculated relative to the period 1880-2009. Data source: Climate Data Center/NESDIS/NOAA

And then they summarize their findings of why it was so hot this year (emphasis added):

Despite 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. It is not known whether, or to what extent, greenhouse gas emissions may affect the frequency or intensity of blocking during summer. It is important to note that observations reveal no trend in a daily frequency of July blocking over the period since 1948, nor is there an appreciable trend in the absolute values of upper tropospheric summertime heights over western Russia for the period since 1900.

The indications are that the current blocking event is intrinsic to the natural variability of summer climate in this region, a region which has a climatological vulnerability to blocking and associated heat waves (e.g., 1960, 1972, 1988)…


Figure: July time series of (top) near surface temperature anomalies averaged over the region 50-60N, and 25-55E and (bottom) anomalies of mid-latitude blocking days averaged between 25E and 55E. Anomalies are calculated relative to the period 1948-2010. Data source: NCEP/NCAR reanalysis.

This is pretty clear assessment. No need to invoke global warming to explain why it is so hot this summer in Moscow, and no indication in the historical record that the events responsible for the heat wave have been trending an a manner that would indicate a global warming influence.

Now, just for fun, lets compare the PSD finding that “greenhouse gas forcing fails to explain the 2010 heat wave over western Russia” with what has been splashed all over the media in recent days:

From Reuters:

Devastating floods in Pakistan and Russia’s heatwave match predictions of extremes caused by global warming even though it is impossible to blame mankind for single severe weather events, scientists say.

An even stronger statement from the Grist:

“Climate experts agree: Global warming caused Russian heat wave”

And this from the blog of the Pew Center on Climate Change , in an article written by Jay Gulledge, Senior Scientist and Director of the Science and Impacts Program at the Pew Center on Global Climate Change:

So it is reasonable to conclude that, in aggregate, the documented increase in extreme events is partially a climate response to global warming, and that global warming has increased the risk of extreme events like those in Russia and Pakistan. On the other hand, there is no scientific basis for arguing that these events have nothing to do with global warming.

Perhaps Dr. Gulledge ought to spend a bit of time talking with the folks at the PSD.

Armchair climate analysts can continue to sit back and speculate all they want, but according to folks who study climate dynamics for a living, there is little in the observational record that suggests that global warming had a role in this year’s heat wave in Russia. Nor does it support the inferences that such an event is “consistent” with climate change.

Now, of course, the government scientists at the PSD know better than to dismiss the importance of global warming on such events altogether, and so while they find that greenhouse forcing doesn’t explain this summer’s heat wave, they speculate that it very well might in the future. For example:

It is clear that the random occurrence of a summertime block in the presence of the projected changes in future surface temperature would produce heat waves materially more severe than the 2010 event.

And

Whereas this phenomena has been principally related to a natural extreme event, its impacts may very well forebode the impact that a projected warming of surface temperatures could have by the end of the 21st Century due to greenhouse gas increases.

But such statements fail to give full acknowledgement to the fact that global warming is supposed to be increasing the intensity and frequency of heat waves such as this one already, and according to the PSD’s own analaysis, it hasn’t. So why should we be big believers that it will in the future?

Or even more unbelievable, that if the intensity and frequency of heat waves do increase in the future, that Muscovites et al. won’t become better prepared for them incorporating the same set of adaptations that we have in America—adaptations which have led to an overall decline in the rate of heat-related mortality in large U.S. cities despite rising urban temperatures.




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