A friend e-mailed me an article stating that “Statisticians Reject Global Cooling.”
http://www.msnbc.msn.com/id/33482750/ns/us_news-environment?wid=18298287
Here was my response:
As far as global warming goes, any way you slice it, global surface temperatures since 1998 have still not exceeded the high reached in 1998. Basically the article seems to be saying that this could easily be the result of chance, i.e. natural fluctuations in the temperature. Which is true, except that I don’t think enough is known about the natural causes of temperature variations to say anything meaningful one way or another.
To me, asking whether cooling since 1998 is statistically significant is the wrong question. Instead, one needs to ask what, if anything, the warmists predicted and whether that prediction came true.
One can ask hypothetically what would have happened if we had set a new temperature record in 2008. You can bet that the warmists would have been screaming about it from the rooftops and presenting it as strong evidence in favor of their hypothesis. Which leads me to ask: What would need to have happened to undermine or falsify the warmist position?
The way science normally works is that you test a hypothesis by making a prediction and seeing if reality matches that prediction. If so, it’s evidence that your hypothesis is correct. If not, it’s evidence that your hypothesis is wrong. But global warming science doesn’t seem to work this way. Any time a warming event happens, such as a hot year or a melting glacier, it’s presented as evidence in favor of the warmist hypothesis. If a warming event does not happen (or a cooling event happens), it is explained away as natural variation.
As far as I know, the warmists’ computer models predicted fairly stead warming, year after year, with an average of 2 to 3 years between each new temperature record. So 11 years without a temperature record is a big problem for them, in my opinion. Even if it’s the result of “natural variation,” it shows that there is some unknown factor which is important and which is not properly accounted for in the models.
Brazil84's Weblog 
February 8, 2010 at 11:25 am |
“As far as I know, the warmists’ computer models predicted fairly stead warming, year after year, with an average of 2 to 3 years between each new temperature record. ”
Which models?
February 8, 2010 at 12:15 pm |
“Which models?”
Apparently, whichever models are used by the IPCC.
See here:
http://www.realclimate.org/index.php/archives/2008/05/what-the-ipcc-models-really-say/
Note the third graph from the top, which is entitled “How Long Might You Wait for a New Record?”
February 12, 2010 at 9:03 pm |
http://www.realclimate.org/index.php/archives/2010/01/2009-temperatures-by-jim-hansen/#more-2743
“What about the claim that the Earth’s surface has been cooling over the past decade? That issue can be addressed with a far higher degree of confidence, because the error due to incomplete spatial coverage of measurements becomes much smaller when averaged over several years. The 2‐sigma error in the 5‐year running‐mean temperature anomaly shown in Figure 2, is about a factor of two smaller than the annual mean uncertainty, thus 0.02‐0.03°C. Given that the change of 5‐year‐mean global temperature anomaly is about 0.2°C over the past decade, we can conclude that the world has become warmer over the past decade, not cooler.”
In other words, your argument appears to rest on a mis-reading of the actual evidence. The article linked above shows that 2005 was the hottest year so far, not 1998.
February 12, 2010 at 10:56 pm |
“In other words, your argument appears to rest on a mis-reading of the actual evidence.”
First, it looks to me like the chart you cite to, by relying on 5 year running means, is hooking the significant temperature rise from 1993 to 1998 into the calculation. Agreed?
“The article linked above shows that 2005 was the hottest year so far, not 1998.”
I agree that according to GISSTEMP, 2005 was the hottest year so far. However, the other 3 leading indicators — HADCRUT, UAH, and RSS — all show 1998 as hottest. Agreed?
February 18, 2010 at 10:38 am |
kent, since you did not respond to my post, my conclusion is that my reading of your source is correct. That the author demonstrates his conclusion of post-1998 warming by averaging in pre-1998 temperatures and also by cherry picking his data set.
February 21, 2010 at 5:32 am |
Umm, what? You sure do like to jump to conclusions.
I’m surprised, but at the same time not surprised, by the irrationality of this last comment.
A more rational thought would have been that I didn’t bother to come back here because I have better things to do with my time.
So … why am I here right now? I found more weird stuff from you on lesswrong and happened to remember that I visited here before. And it’s late on a Saturday night and I’m wasting time. But enough with the wasted time!
February 21, 2010 at 4:14 pm |
“Umm, what? You sure do like to jump to conclusions.”
In this case, it is hardly an outrageous conclusion since it was based on the source you yourself provided.
“A more rational thought would have been that I didn’t bother to come back here because I have better things to do with my time. ”
Even if that’s the case, why should I doubt my earlier reading of your source?
Anyway, why not just answer my questions?
First, it looks to me like the chart you cite to, by relying on 5 year running means, is hooking the significant temperature rise from 1993 to 1998 into the calculation. Agreed?
Second, while I agree that according to GISSTEMP, 2005 was the hottest year so far, the other 3 leading indicators — HADCRUT, UAH, and RSS — all show 1998 as hottest. Agreed?
Two extremely simple questions. Why not answer them?
February 25, 2010 at 10:35 am |
Just to follow up on my previous post, I note that “Kent” seems more interested in meta-debate than in actually discussing the issues he raised.
Looks to me like (1) he’s the one who misread the actual evidence; and (2) he would prefer to avoid that uncomfortable subject.
I’m going to guess that he responded to my post simply by doing a google search of Realclimate, then linking to the closest post he could find without reading or thinking about it very carefully.
But who knows? Maybe I’m wrong and I’m the one who misread the evidence and/or the realclimate article. The starting point to educate me is the 2 questions I asked.
March 2, 2010 at 5:14 pm |
P.S. One thing I’ve noticed over the years is that when people are asked challenging questions which expose the weaknesses in their position, it’s very common for them to suddenly get “too busy” to respond.