There is a news article in the Guardian on July 4 2012 by John Vidal titled As the climate changes, extreme weather isn’t that extreme any more
This is a good example of the type of reporting that my son talked about in his post A Handy Bullshit Button on Disasters and Climate Change
In his post he writes
Anytime that you read claims that invoke disasters loss trends as an indication of human-caused climate change, including the currently popular “billion dollar disasters” meme, you can simply call “bullshit” and point to the IPCC SREX report.
The Guardian article includes the remarkable statement that [highlight added]
There’s always been freak weather, but climatologists increasingly think these events are becoming less unusual. Instead of taking place every 10 or 20 years, they are happening every two or three. This, they are beginning to say, is the new normal, a taste of the future as the planet warms.
Apparently, it is okay to “think these events are becoming less unusual” to make the statement true. However, the reality is not definitive with respect to extremes. We examined this in our paper with respect to the European 2003 heat wave
Chase, T.N., K. Wolter, R.A. Pielke Sr., and Ichtiaque Rasool, 2006: Was the 2003 European summer heat wave unusual in a global context? Geophys. Res. Lett., 33, L23709, doi:10.1029/2006GL027470.
Chase, T.N., K. Wolter, R.A. Pielke Sr., and Ichtiaque Rasool, 2008: Reply to comment by W.M. Connolley on ‘‘Was the 2003 European summer heat wave unusual in a global context?’’Geophys. Res. Lett., 35, L02704, doi:10.1029/2007GL031574.
and our conclusion was confirmed in
Connolley W.M. 2008: Comment on “Was the 2003 European summer heat wave unusual in a global context?” by Thomas N. Chase et al. Geophys. Res. Lett., 35, L02703, doi:10.1029/2007GL031171.
It is only with robust scientific assessments will the answer be obtained as to whether the frequency of extreme weather has changed.
The last sentence of the Guardian article shows that this “news” article is really an op-ed. John Vidale writes
This is a most dangerous period. We still have a very good chance of avoiding the worst of climate change but the collective will to try to do anything appears to be weakening and confidence in politicians is at rock bottom. Unless the climate of opinion changes, the present economic storms may seem as nothing.
The current distribution of cool and warm extreme events certainly warrants explanation. As I have posted in
Perspective On The Hot and Dry Continental USA For 2012 Based On The Research Of Judy Curry and Of McCabe Et Al 2004
it is the spatial arrangement of atmospheric and ocean circulation features that matter much more than a global average surface temperature anomaly. As shown in the University of Alabama at Huntsville data for May 2012 (see), for example, the lower tropospheric temperature anomaly is just +0.29 C above the 30 year average. As shown by Bob Tisdale (see) the global averaged sea surface temperature anomaly for June (from the Reynolds OI.v.2 SST) is only +0.191 C above its long-term average.
While humans certainly are influencing the climate system, “global warming” (whether caused in part, or even all, by humans) seems to be a rather small component. As we wrote in one of my first weblog posts in 2005
What is the Importance to Climate of Heterogeneous Spatial Trends in Tropospheric Temperatures?
“…regional diabatic heating produces temperature increases or decreases in the layer-averaged regional troposphere. This necessarily alters the regional pressure fields and thus the wind pattern. This pressure and wind pattern than affects the pressure and wind patterns at large distances from the region of the forcing which we refer to as teleconnections.”
It is these regional circulation features that are the reason for the current heat wave in large parts of the USA and the ”lost summer” of 2012 in Europe. John Vidale, in his Guardian news article, ignores presenting evidence that human activity is the reason for the current spatial pattern of atmospheric and ocean circulations, and how they would be different without human effects. He has grossly oversimplified how the real climate system behaves.