10 March 2011

Attribution and the Russian Heat Wave

Some of my NOAA colleagues here in Boulder have a new paper forthcoming in Geophysical Research Letters (PDF) looking at last summer's heat wave in Russia.  They conclude:
Our analysis points to a primarily natural cause for the Russian heat wave. This event appears to be mainly due to internal atmospheric dynamical processes that produced and maintained an  intense and long-lived blocking event. Results from prior studies suggest that it is likely that the intensity of the heat wave was further increased by regional land surface feedbacks. The absence of long-term trends in regional mean temperatures and variability together with the model results indicate that it is very unlikely that warming attributable to increasing greenhouse gas concentrations contributed substantially to the magnitude of this heat wave.
Such attribution, they warn, may only be a matter of time:
To assess this possibility for the region of western Russia, we have used the same IPCC model simulations to estimate the probability of exceeding various July temperature thresholds over the period 1880-2100 (Figure 4).The results suggest that we may be on the cusp of a period in which the probability of such events increases rapidly, due primarily to the influence of projected increases in greenhouse gas concentrations.
It would be interesting to assess how much time such attribution might take using a method similar to what we used for detection of trends in hurricane damage under model projected futures.

For an earlier discussion see this, and thanks KK.


  1. 'It is only a matter of time' is in conflict with a vast number of claims from the AGW promotion community.
    The promotion community claims the evidence is clear, incontrovertible and 'worse than expected'.
    In the real world it cannot be both, but in the age of AGW, it is always both.

  2. What the Russian heat wave shows us more that anything is just how vulnerable we are globally to the knock on effects of extreme events like this on.

    If I understood correctly, whilst the magnitude is not exceptional give past variability and local factor, NOAA conclude that the probability of exceedance should increase in a warming world.

    The even in my eyes still serves to highlight the attention that should be paid to reducing such vulnerability.

  3. Well kudos for giving Trenberth and co a bloody nose but I think they'll be back for more. And then they go and spoil it all...

    On the other hand, by exactly the same weaselly reasoning as "may be", we may not be near any cusp at all. The models in fact suggest nothing. Only those interpreting some of the results of some models are suggesting anything. And this is on the basis of models that have correctly predicted exactly nothing so far. Not surprising really since they don't have the capability to predict weather events in the first place.

    How do you become a scientist these days: is it just a lucky dip?

  4. While a temperature event doesn't get attributed by NOAA to climate warming/AGW, it DOES go into the temperature record of the globe, and shows up as part of the global warming record!

    So all this 'understanding" by Hansen/NASA is, next year, proof of their CAGW meme.

    Wow! They have it both ways! Any one else realize this?