Greenhouse Gas global warming (as opposed to other sources) should be measured in the tropical troposphere, because the models say that is the signature of greenhouse gas warming: the tropical troposphere should warm at roughly twice the surface rate. To verify this, see for example Figure 9.1, p675, Vol 1 IPCC Report. http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter9.pdf (The whole report can be found at http://www.ipcc.ch/ipccreports/ar4-wg1.htm .)
This was always an embarrassment for global warmists, because the troposphere has never warmed much, but in the last few years its cooled. The tropical troposphere has now not warmed at all. See http://www.climateaudit.org/?p=3048 for the graph of temperature according to three satellite series since 1978.
The Radiosonde (weather balloon) data series is an independent measurement of the tropical troposphere temperature. It goes back to 1958 and is presumably extremely reliable, because all they are doing is sending thermometers up in balloons. You can see the time series at: http://www.climateaudit.org/wp-content/uploads/2008/06/hadat42.gif The graph is flat, and the most recent data point is the coldest.
...This shows that the IPCC's GCM's (Global Circulation Models) are wrong. Not that it can be too surprising that the GCM's are worthless since p 596 of the IPCC 4th report cautiously admitted they didn't know whether their GCM's had more data points or free parameters! Yet the GCM's are absolutely central to any argument for expecting warming by more than a few tenths of a degree by 2100, and to the amazingly porous argument the IPCC report gives to demonstrate man caused the alleged observed warming.
...The IPCC 4th report says "attribution of anthropogenic climate change is understood to mean demonstration that a detected change... is not consistent with alternative, physically plausible explanations."[p668] But the report contains several alternative possibilities that are said to be "not understood" or whose magnitude is said to be "largely unknown". For example, two are mentioned just in the last paragraph of 1.4.3. (p108): unknown large feedbacks from changes in solar irradiance, and the effects of galactic cosmic rays. Actually, as I point out in the above few paragraphs, cosmic rays seem to explain climate fluctuations extremely well. The IPCC devotes considerable space to the strawman that solar activity could directly affect the earth's temperature, but ignores the actual indirect means by which solar variation seems to affect temperature. Global Warmists routinely attack the strawman of direct solar effect any time the subject is raised.
Also, Mars, Jupiter, Triton, Neptune, and Pluto have recently been observed warming, suggesting some cause external to the earth, but none of them are mentioned anywhere in the 987 pages of the 4th Report. Another physically plausible explanation for recent warming (if indeed warming has actually occurred) as remarked by Lindzen would be thermal transfer from the deep oceans. The oceans and atmosphere are turbulent fluids prone to exchange heat in unpredictable ways over a wide range of time scales simply because chaotic systems do that kind of thing, which the computer models of the IPCC are completely inadequate to simulate.
Its also worth noting that intuitive physics (and pencil and paper calculation) says that greenhouse gas warming scales logarithmically. The theoretical reason for the effect is that CO2 molecules (for example) absorb and reflect certain wavelengths. But they only do it in certain wavelengths. Once you've got some molecules of CO2 in the air, the effect of each next molecule is less than the one before, because those wavelengths are already getting scattered, and mostly heat is already only getting out in other wavelengths. So even if you believed everything else, one's expectation would be that we've already seen the substantial majority of all the warming we will ever see, if we quintuple the CO2 from here. To believe otherwise, you have to rely in detail on the GCM's prediction of positive feedbacks, that they are not competent to calculate, to predict warming in the future that is several times greater than anything we've seen before.
Monday, December 08, 2008
Help! -- climate change
Some of the readers of this blog know much more about climate change than I do. Could someone please comment on this web page of Eric Baum's, in which he claims the evidence for human causation is weak and that state of the art climate models are shoddy? (Excerpts below.) Baum is a brilliant guy -- former theoretical physicist and AI researcher. I've recommended his book on AI here before.
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A good resource for the straight-dope on climate change is www.realclimate.org.
They do not address Baum's web page directly, so far as I can tell, but they do address some of the ideas mentioned there:
On the tropical troposphere, see http://www.realclimate.org/index.php/archives/2008/10/tropical-tropopshere-iii/ and references therein.
On cosmic rays, see http://www.realclimate.org/index.php/archives/2007/10/cosmic-rays-don%e2%80%99t-die-so-easily/ and references therin.
Baum glibly dismisses the role of positive feedbacks -- this seems very naive, and I'm sure you can find essays on realclimate arguing so.
Regarding "urban heat island," see http://www.realclimate.org/index.php/archives/2007/07/no-man-is-an-urban-heat-island/ and references therein.
Baum says ludicrous things like "Since then the hockey stick was invalidated."
Anyway, this is just to help after glancing over Baum's web page. It seems to me that Baum is merely recycling all the contrarian arguments, which are known and repudiated by active climate scientists, but which get repeated over and over again online because there is no scientific review of online content.
It looks like the URLs I posted are chopped off. To find the pages I found, simply use realclimate's search function, typing in "troposphere", "cosmic rays", "urban heat island", and such... and scroll down for the best hit.
The ratio of badness of a Type I error and a Type II error wrt climate change is so apocalyptically asymmetric, I have no idea why we're even still discussing whether it's 100% certain.
From the point of view of risk management, this dynamic of skeptics taking pot shots at climate modeling seems way off base. Uncertainty in the outcome of modifying CO2 levels is not a good argument for continuing to modify CO2 levels. If someone has an airtight proof that unrestrained CO2 emissions will have no disastrous consequences, then that would be worth exploring.
There is nothing ludicrous about the statement, "Since then the hockey stick was invalidated."
For example, the hockey stick controversy has its own Wikipedia article:
http://en.wikipedia.org/wiki/Hockey_stick_controversy
For a physicist's take on the hockey stick, view this blog where the author produces the hockey stick from Brownian thermometers. You can even inspect his Mathematica code.
http://motls.blogspot.com/2008/12/ccnet-eight-articles-about-climate.html
Obviously climate modeling is primitive. That's not the issue.
For me the interesting thing is that the actual warming/melting, etc. is progressing *faster* than the models have been predicting. The cycle is like: scary model announced, new data is gathered, modelers shocked by scope of change, model revised to be scarier.
It's possible, of course, that the real climate process will suddenly do a big U-turn for reasons that haven't been captured in the existing models. But to set policy by that, you would need to have even greater confidence in these hypothetical U-turn generating processes than we do in the current scary models.
It's true that we need to assess the potential costs of avertable global warming along with the probability that those models are in fact correct.
However, it is not at all obvious that the cost of such warming will be greater than the inefficient, political, and fundamentally costly regimes necessary to contain that warming. Humans are both better able to adapt to changing environments and much worse at making sound public policy than most environmental advocates would like to admit.
Let's take a look at the argument that "Mars, Jupiter, Triton, Neptune, and Pluto have recently been observed warming", as a simple example. An obvious question, which I'd expect any scientist to ask, is what is happening on Mercury and Venus--why aren't they on the list? Perhaps there's some good reason for their absence, but I'd expect to see that addressed in a serious argument.
Worse, looking at the planets that are listed, Pluto's climate is completely dominated by its orbital eccentricity of 0.25--if Pluto is getting warmer, it's because it is getting closer to the sun, as there's no plausible level of solar variability that could beat its eccentricity. The same is true to a lesser extent of Neptune, with an eccentricity of 0.01 (Uranus is 0.04, so statistically it's no big surprise to find 2 out of 3 getting warmer), and Jupiter's climate is dominated by internal gravitational heating.
Obviously I cherry-picked that as the simplest example, but the same lack of seriousness pervades the piece. It's a polemic, not a serious scientific argument.
why does anyone care? it is as irrelavent as how many angels can fit on the head of a pin. all environmental problems have the same cause, too many people.
http://www.springerlink.com/content/au9x40l201105273/fulltext.pdf
A basic point of physics:
1) the oceans are warming
2) the oceans interface with the
atmosphere and pass on this extra
heat flux
3) the atmosphere disperses it throughout area which delivers the
most excess heat flux to the ground
at high latitudes
4) temperature increases since the
mid 1970's are most pronounced
at high latitudes
Eric (Baum?), you would do well not to invoke anything on Lubos Motl's blog, if you want to be taken seriously.
Can't help with the climate business, but thought you might be interested in this:
Can science help solve the economic crisis?
A major weakness in the GCMs is their treatment of cloud physics, which is an important part of the CO2-water vapor feedback. Since the cloud physics operates on a scale much smaller than a resolution cell of a GCM, the modelers must use a collection empirical approaches with tunable parameters. Who knows if these empirical models are even correct?
John A. Wheeler once said that a physicist should never calculate anything he doesn't know the answer to. In other words, running computer models should act as a refinement on something you already understand with the model. The IPCC has turned Wheelers dictum around. Do we really want to damage the world's economy on the basis of computer models?
After you've checked out the AGW polemics at realclimate you should do a reality check at www.climateaudit.org.
I presume this is in your neck of the woods and you may recognise some of the signatories
http://www.petitionproject.org/gwdatabase/GWPP/Seitz_Letter.html
Additional essays on climate change as well as critiques of the IPCC are available at http://gemarsh.com Click on Global Warming.
All this nitpicking about climate model details really misses the point. Rather than discussing the degree to which humans are responsible, we should be discussing our response - even if humans are not at all responsible, the fact remains that climate is changing and we must adapt accordingly.
An interesting framework for such a discussion appears in Bjorn Lomborg's latest book "Cool It". It's a short read and worth it.
PT, that's like saying, "I don't care whether or not it's the smoking that is making me ill, the question is what I can do about my yellow teeth, chest pains, and worsening cough."
Steve-
I would like start by agreeing with you that Baum is a bright guy and appears to be objectively approaching the question. Two it appears that the consensus on warming is cooling rapidly. Three
I fear that a few of the comments being posted suffer from serious ideological biases that leave their expertise in "risk" management worthless. Third realclimate.com is not an objective source given that they have an openly advocacy position and squelch debate from credible scientists.
Many global warming theorists have gravitated to the precautionary principle. This principle is largely a rhetorical device. To invoke it when making claims leaves a material question unanswered, what is probability of cooling?
What is the evidence that "the consensus on global warming is cooling rapidly"? My impression is, every year that passes the support only becomes stronger. It was just last year that the latest IPCC report basically strengthened all conclusions on this matter.
How does realclimate.org squelch debate from credible scientists? It seems to me they criticize 'analyses' that they find seriously flawed, and have an open comment section for responses. I have always found their arguments more compelling than their opponents'.
I say we just keep up with business as usual. After all, if we turn out to be wrong, we can always ask Mother Nature* for a bailout. I'm sure she'll be happy to give us one. :)
[* By the way, does anybody have her contact information?]
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