Like Alex Trebek, the bunnies know the answer, there were humongous heat waves in Texas (2011), Russia (2010) and Europe (2003), but what is the question? Otto, Massey, Oldenborgh, Jones and Allen (Allen being Myles) have two answers, but their answers untangle much of the to and fro about these events. Their bottom line is that the slightly warmer weather event crowd and the climate dice are loaded bunch are both right, because they are asking different questions.
The first asks whether similar heat waves can be found in the meteorological records. The answer, is that similar, although perhaps slightly cooler heat waves can be found in the meteorological records of all these areas, and that the slightly increased temperatures might be a sign of climate change or simply natural variability. Therefore the heat waves are not convincing markers of climate change. Dole, et al "Was there a basis for anticipating the 2010 Russian heat wave?", Geophys. Res. Lett., 38, L06702, doi:10.1029/2010GL046582 have been pushing this answer, and, of course, any number of Eli's friends.
The second asks how frequent such heat waves were in the past and are now. Here one finds a significantly higher percentage of extreme (three sigma) events and assigns the recurrence of such events and the events themselves as markers of climate change. Hansen, Ruedy and Sato and Rahmstorf and Coumou (2011), "Increase of extreme events in a warming world", Proc. Natl. Acad. Sci. U. S. A., 108(44), 17905–17909. are two of those holding this view. On the bloggish side Michael Tobis has been the strongest voice.
Otto, et al., have a nice figure illustrating this. Using climateprediction.net they created a large ensemble which they examined for significant heat waves.
"These two approaches are different but complementary in quantifying the role of human influence on a 2010-like Russian heat wave. This is illustrated by Figure 4, which shows return times of the heat wave conditions for the 1960s (green) and 2000s (blue). The threshold exceeded in 2010 is shown by the solid horizontal line, which is more than 5°C above 1960s mean July temperatures, shown by the dashed line. The difference between the green and the blue lines could be characterized as a 1°C increase in the magnitude of a 33-year event as shown by the vertical red arrow. This arrow is substantially smaller than the size of the anomaly itself, supporting the assertion that the event was “mainly natural” in terms of magnitude which is consistent with D11. Alternatively it could be characterized as a three-fold increase in the risk of the 2010 threshold being exceeded, supporting the assertion that the risk of the event occurring was mainly attributable to the external trend."
Rabett Run might throw a link at John Nielson Gammon who got that there were two parts
although he would not have won the Daily Double.In other words, nature made it a record. Climate change made it a phenomenal record.
Posted by EliRabett at 2:21 PM