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• Hi Shaviv -

I'm one of those "general scientists," actually a theoretical biologist, who voted "mostly natural," but who ranks "Nobody knows" a close second. My reasons as follows:

1. The climate system is a complex nonlinear system, undoubtedly chaotic, quite likely turbulent, i.e., high dimesional, with apparent recurrence when projected onto low-dimensional subspaces on multiple time scales. Nothing that I have seen in the climate change / AGW literature comes close, even remotely, to grappling with this issue. Instead, one encounters a plethora of time series, which means you're going from n --> 1 (n being the dimension of motion). Even if n were on the order of 3 or 4, this is fitting reality to pretty Procrustean bed. One also enounters a pelthora of arcane statistics, a sure sign that the system is poorly understood.

2. As an academic who's occasionally rubbed shoulders with some of the climate change principals, I am convinced that most of them support the AGW hypothesis for reasons that have nothing to do with science: greed (power, \$, ...), ideology, and so forth. In this regard, I judge them of a piece with Creatiionists whose opinions on evolution are informed by extraneous concerns. Of course, one can be right for the wrong reasons (Lyell on "non-progressionism" - he believed that once the data were in, the major taxonomic groups, e.g., mammals, would all go back to the beginning) or wrong for the right ones (Lamarck on transmutation - he believed that Nature would not allow old species to have gone extinct, so they must have evolved into new ones), but science in the service of non-science is a contradiction in terms.

Obviously #1 doesn't exclude periodic forcing from without, nor the possibility that it accounts for a significant fraction of the variance on suitably chosen time scales.

With best wishes.

Dec 29, 2011
• In response to the posted poll- What "20th century climate change" are you referring to here??

Its all very well posting up a poll but the questions already a loaded one, the allusion that there actually IS any out of the ordinary "climate change" occuring.
Wheres the proof of anything of the usual humdrum planetary systems functions going awry?
Timescales are vitally important here, climate change cant be meaningfully measured, gauged or otherwise monitored over such miniscule timeframes as the human existence, you not only need a much larger sample timeframe but you also need a better question, preferably not a loaded one.

Jan 01, 2012
• I have to disagree with you. The term climate change is not loaded at all and it does not allude to anything out of the ordinary, at least not in my book! The 20th century average temperature has changed, as it always has (e.g., if use the satellite data and avoid the problems of surface measurements, you see that since the late seventies, the temperature of the lower troposphere increased by about 0.4°C). So, there was climate change in the 20th century. One can argue how large it was, or what are the causes, but not that it is occurring (note that I even didn't say global warming, just change).

Jan 01, 2012
• Well in that case, we'll have to agree to disagree.

Your question essentially states "what is the cause of 20th century climate change" without offering any proof that the climate has actually "changed" to anything different from its usual chaotic state.
Therefore, the question does indeed allude to something abnormal being somehow observed in some esoterical manner, otherwise why include "20th century climate change" in the question?
The assumption that there IS some abnormal difference to the climate of the 20th century, that there is somehow an observed cause is the problem here.
There is no observable difference because the sample timescales for such observation are simply too short to have any kind of significance, let alone be attributable to any human causes, which is obviously the inference in the question.
Yes, the climate changes, yes it always has, yes it always will and yes, it will do that as long as we have an atmosphere.
So the troposhpere heated up this century, so what? That just means it was cooler prior to that. The question you need to ask is: Was it warmer or cooler before it warmed or cooled before it warmed or cooled? repeat ad infinitum.....

Jan 02, 2012
• it's my blog and I can ask whatever I want ;-)
More seriously, I don't think that we think that different. Both of us realize that the nature of climate is to change.

Jan 02, 2012
• Yes, ill agree with you on the nature of climate, ie, that it changes, its just a pity that those with an agenda or just blind faith cant see that.

Ill say this.
All most people want is the truth, dont need a sugar coated version of it, dont need it sprinkiling with agw doom either, just bare, straight facts for people to look at and try to get a handle on, thats why i took exception to the poll question, and i still maintain its slanted. :p

Hapy new year all the same. :)

Jan 02, 2012
• "c'mon! It's utterly disingenuous to claim that your poll question is neutral. what if you had asked, " What is your expertise, and what is the cause of 19th century climate change?

The only correct answer would have been : HUH?

Or how about "What is your expertise, and what is the cause of 21st century climate change?"

The only correct answer would be, "What climate change?"

Ask the question again, thusly: "What is your expertise, and do you think the climate is changing unusually, and, if so, what is causing those unusual changes?"

Jan 02, 2012
• Whether we want to admit it or not, there was climate change in the 20th century (just as there was in the 19th, and as there will be in the 21st). I simply don't leave an option for people not to admit it!
In any case, this poll is not something to be taken too seriously. I simply wanted to characterize the audience I have here, whether they are more alarmist or more skeptic in nature, whether they are more profesional or not, and more interestingly, whether there is any correlation between the scientific background and their views.

Jan 02, 2012

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