2011-09-25 06:18:56Texas Drought and Global Warming
John Hartz
John Hartz
john.hartz@hotmail...
98.122.98.161

Here’s the summary of a detailed examination of the relationship between climate change and the Texas drought. Our SkS experts in the science of claimate change may want to review the methodolgy used in the analysis. Both the authors and the commentors seem to know their stuff.

Precipitation: The balance of evidence does not support the assertion that the rainfall deficit since October 2010 was made larger or more likely by global warming.

Temperature: Compared to long-term averages of summer temperature, the rainfall deficit accounted for about 4 F of excess heat and global warming accounted for about 1 F of excess heat.   Warmer temperatures lead to greater water demand, faster evaporation, and greater drying-out of potential fuels for fire.  Thus, the impacts of the drought were enhanced by global warming, much of which has been caused by man. [edited 9/11/11]

Source: “Texas Drought and Global Warming” by John Nielsen-Gammon, Climate Abyss blog, Houston Chronicle, Sep 11, 2011

Nielsen-Gammon's bonda fides are impressive. Is he in the pro-AGW camp? 

2011-09-25 09:51:01
Tom Curtis

t.r.curtis@gmail...
112.213.178.133

John, there is an extensive discussion of that article by Michael Tobis, at  Only In it for the Gold:

http://initforthegold.blogspot.com/2011/09/nielsen-gammon-vs-new-normal.html

 

Tobis's argument is that with so many recent, very unusual climate events, assumption that Earth continues in the old climate state is unwarranted.  That assumption is necessary for the type of analysis performed by Nielsen-Gammon.

 

While Tobis' argument is cogent, I am not yet convinced.  We have only had a few years of the "new normal" if that is what it is.  It may yet be just a statistical fluctuation.  On the other hand, we also do not know as yet that Nielsen-Gammon's assumption of same ol' same ol' is warranted.  Therefore his conclusions can only be accepted with heavy qualification.

 

Tamino also has a germaine discussion, and produces this graph highlighting the years since 2000:

 

The hot bias of the post 2000 years does suport the idea of a new normal, but 2011 is still an outlier even for that period.  Does that mean the climate system is changing so fast at the moment that talk of "normal" makes no sense?  Obviously, again, it is too early to say - but we live in interesting times (unfortunately).

2011-09-25 09:51:33
Tom Curtis

t.r.curtis@gmail...
112.213.178.133

Link to Tamino's discussion:

http://tamino.wordpress.com/2011/09/21/god-help-texas-rick-perry-wont/

2011-09-25 13:53:50Rolling 13s
muoncounter
Dan Friedman
dfriedman3@comcast...
76.30.158.238

I understand the need for tentative language, but it gets tedious.  You have to wonder how many standard deviations beyond the mean can be wished away.  Every time we see an extreme weather or similar thread, out come the 'its blocking' or 'its PDO/AMO/XYZ.  Tobis is working on a more detailded post; in the meantime, there's Rabett's Rolling 13s.

2011-09-26 00:13:43
John Hartz
John Hartz
john.hartz@hotmail...
98.122.98.161

Also see Meehl's analogy in Home Runs and Climate Change: A Sports Analogy  It's the best one that I have come across.

2011-09-26 02:33:32Drought monitors
muoncounter
Dan Friedman
dfriedman3@comcast...
76.30.158.238

The map I posted in reply to Norman's ever-present 'no its not' commentary comes from the NOAA North American Drought Monitor.  It allows choice of time interval to compare to the long term average.  The UCL climate extremes page provides a global view.

2011-09-26 14:42:35i should stop characterising people
jyyh
Otto Lehikoinen
otanle@hotmail...
193.66.74.38

(imho John N-G is a scientist so he is pro-AGW, he just sticks to the IPCC reports, and easily omits the most recent results. as he is the state climatologist, he also likes to consider issues within climate science solely on the point of the respective state (basically what M.Tobis was saying). the position he's in might make him the most mildly speaking climatologist of the world excluding some arab states (well maybe russia too, don't know for i can't speak russian))

Oct-5th

And now he's proven me wrong by making an excellent article on combined effects of Atlantic/Pacific SSTs (including very recent studies) and their effects on southern states. Furthermore he has knowingly approved to let out a headline in a press release "The current Texas drought  could last until 2020.", and that's not a mild statement.