Recently the Associate Press reported a story about an enormous ice island that broke off from the Greenland ice sheets. The Petermann Glacier is four times the size of Manhattan.
Representative Ed Markey, Chairman of the Energy Committee, says that the island should serve as a home for global warming skeptics. This is known as rational debate. The existence of the island is said to show the truth of global warming. The Petermann glacier “may symbolize a warming world like no other.”
Further into the article we find that this glacier is the largest since — 1962.
I’ve been digging into the theory of man-made global warming, and I keep getting steered in circles; it seems the principal argument is, the Earth is warmer than the black-body temperature would predict given energy received from the Sun and that radiated back out to outer space. Since the Earth is too warm, something has to account for it. The only thing the climatologists believe can account for it is greenhouse effect — which certainly seems to have heated Venus — and therefore it must be the explanation since we have no other.
I have had an AGW “believer” lecture to me in what amounts to baby talk — assuming that if he talks real slow I will understand — and that was his principle argument: the Earth is too warm, greenhouse effect explains Venus, and it’s all we have to explain the excess heat on the Earth. The computer models all say that’s what’s happening and no one has anything better. Therefore we accept AGW. That, my boy, is science.
Again I may sound as if I were parodying the argument but in fact I am not.
At this point I thought, “I’ve written most of this before” and went looking for when. The result is that I dug it out of another conference. The discussion was a lot longer than what I am giving you here, and what follows is pretty long. I post it because I am still interested in the debate, and the discussion in this other conference didn’t get me very far. Apologies for the length, but the question is one of importance, and rational debate isn’t always brief. Alas, I am not sure the debate got me very far, but I tried. My partner in the debate is a Ph.D. physicist, reasonably well known, and very clearly a believer in human-caused global warming.
After a number of interchanges in a conference of fairly smart people, the physicist apologist for AGW replied to me as follows:
Once more: The greenhouse effect is part of the laws of physics. The reason that scientists pretty much dismiss the skeptics out of hand is that, as far as I’m aware, NONE of them have come up with a plausible alternative explanation for why adding carbon dioxide should *not* increase the temperature of the Earth.
(Let me remind you that the natural greenhouse effect is about 30 degrees C: without an atmosphere, the Earth’s radiative equilibrium temperature would be below freezing. The anthropogenic contribution is, in fact, a pretty small perturbation).
It’s fine enough for amateurs to pick through the enormous data record of climate science and say “wait, what about this curve? How about this one?”, but this, actually, is not science. The correct way to do science would be to try to fit those curves to a model, and see how they fit.
Is there a model in which carbon dioxide does NOT cause greenhouse effect warming WHICH FITS THE CURRENT DATA?
Here is the greenhouse effect physics, in a nutshell:
1. the warm Earth emits infrared radiation.
2. some portion of that infrared is absorbed by (infrared-absorbing gasses in) the atmosphere.
3. the atmosphere re-emits that absorbed energy in the from of infrared, isotropically.
4. Some of the infrared radiation emitted from the sky is absorbed by the Earth.
These are all pretty straightforward physical processes (that have been known for a century); if you like you can measure the downwelling infrared with an infrared bolometer, and even spectroanalyze it. This is not new physics. It is covered, for example, in book-length detail in the copy of _Introduction to Atmospheric Radiation_ (1980) on my bookshelf, not to mention dozens of other texts.
Let’s suppose that there is, actually, some (as yet invisible) reason to be skeptical. I will suggest that the current crop of “skeptics” have *damaged* our ability to find it. Overall:
- they ignore back-of-the-envelope physics calculations
- they don’t believe detailed physics calculations based on integrating the absorption spectrum
- they dismiss all the detailed numberical-integration atmospheric models
- they discard the measurements when they doesn’t agree with the conclusion they started with.
Basically, once you discard all the tools that they don’t like the results of, there aren’t any tools left to do science with.
I was tempted to reply in the same tone, but what I said was:
So: we have a serious statement by a serious person, who wants to discard the skeptics and get on with what to do about it since the science is settled.
My first critique is simple:
Historically, warming precedes rises in CO2. This is in accord with normal theory. While it is certainly true that a ‘greenhouse effect” influences climate, historically, CO2 levels have not caused warming; the CO2 levels follow a temperature rise, not precede it.
Arrhenius thought:
(1) that temperatures were rising and had been since 1800. Correct. Historical data. Not a prediction. Observed through the 1800′s.
(2) They would continue to rise as they had been rising. This was more or less projection of an existing trend. That would be about a degree per century. As it happened, the observed temperature rise decelerated (and had been decelerating for a few years) when Arrhenius made that prediction, but temperatures did rise. The NOAA data show 1880 as -.2 below the 1940 “normal” of 0, and “normal” or 0 in 1940. That’s not the 0.5 predicted in 1900 but the trend is in the right direction.
(3) Arrhenius predicted that there would be an “extra” rise of about 2 degrees over a century if CO2 levels doubled. This is theory.
It is now 110 years since he made that projection. We have had under 2 degrees rise in that time period according to the NOAA data.
That is, from 1940 to 2003 it went up about 0.4 degrees. There is a sort of “hockey stick” sharp rise from 2000 to 2009 but these data are a bit controversial. We can agree on about 0.7 C rise =~ to 1.7 F from Arrhenius to now. It’s less than expected, but it is a rise. Call it a full degree C (1.8 F) rise if you like.
(4) you may ascribe that 1 C rise to CO2 if you like, in which case you have to throw out the projection of a continued “normal” 1 C rise that would have happened without CO2. You may ascribe that 1 C rise to the “normal trend” that has been taking place since the end of the Little Ice Age. You don’t get both, because the data show only the 1 C rise, at least as close as I can read the NOAA charts.
[You can see the temperature graphs here. The most often used graph shows the temperature in 1880 as about 0.4 below the "normal" of 0 in 1940 and about that above the normal in the year 2000, giving a rise of about 1 degree in 120 years.]
Why? We don’t have a good theory as to why; but those are the data, and the usual practice in science is that theory has to account for data, not data have to be forced to fit the theory.
Now about the simple back of the envelope accounts: As Dyson points out, CO2 can have an effect only in COLD DRY AREAS. There isn’t much room for “greenhouse” warming in moist areas. Greenhouse effects may — indeed must — be involved in the temperature of the Earth, but clearly we don’t have a good quantitative handle on which ones do what: but surely we can agree that CO2 isn’t what’s happening.
Or: if it is CO2, then the fears of the 1970-1984 doomsters who feared a coming Ice Age are very well founded and the CO2 is what saved us. This is sort of what Niven, Flynn, and I projected in Fallen Angels. That was a work of fiction, and as I have often said, novelists need only be plausible: we don’t have to marshal all the arguments for our case as do advocates, and we certainly do not have to account for all the data. Scientists, however, do have to account for all the data, and none of current models do that.
One theory common in the 1970′s was that warming brought out more moisture, which moved more water vapors around, which was increasing snow falls and that was what was causing the new disastrous coming New Ice Age and Global Cooling that had scared Schneider and Margaret Meade and others, and dominated big science conferences during the 70′s and early 80′s.
What we must conclude is that the models have not predicted what we have observed; nor have we found the stratospheric hot spots that CO2 driven warming predicts we will find. This is not a confirmation of the accuracy of the theories, all of which more or less predict the same results — which results have not been found so far.
For decades we have had two kinds of climate scientists: theorists and observers. The theorists are all pretty strong Global Warming advocates. The observers are a mixed lot, but none of them see what the models predict. The believers among them say “we have not seen them yet.”
More theory: if I want to put CO2 into the atmosphere, I can burn coal and oil, but if I really want to run the CO2 levels up I should warm the seas. I want to bring up a lot of cold water to the surface and warm that. Warming the oceans will really raise the
CO2 levels; how much CO2 for how much temperature rise is calculable, but getting that circulation going is a bit more complicated, and we don’t seem to be able to predict El Nino and La Nina events which have great effects on ocean surface temperatures. As a first cut, if I want more cold water to come higher, I’ll turn on the heat down at the bottom — otherwise known as volcanic events.
And if I want something to worry about, I’ll worry about how to remove a great big lot of CO2 that we could get if the oceans warm.
That could really cause a runaway hockey stick temperature rise. Could. It’s not inevitable. I’d think some investment in developing engineering methods to really clean out CO2 from the atmosphere would be prudent. We may not need the techniques, but if we do, we are going to need them bad.
So: I don’t think Dyson and Baliunas and Singer and the other skeptics are ignoring the back of the envelope calculations: but they are pointing out that the data don’t seem to be reconciled with the theory. As to “-they dismiss all the detailed numberical-integration atmospheric models” perhaps they should until the detailed numerical models can take a set of initial conditions and generate a good fit to what actually happened.
As to the greenhouse effect itself, who ever thought there wasn’t one? And perhaps that is what is saving us from living on a ball of ice. Perhaps not. But I fail to see how investing in better models — they get better when questioned, and I doubt they get better by setting up “peer review” so that anything that doesn’t approve of the -the detailed numberical-integration atmospheric models  gets ignored.
Present policy seems to be to spend billions in ways that will have a pretty small effect on the CO2 released into the atmosphere and even less effect on the actual warming — this according to the detailed numberical-integration atmospheric models which show that Kyoto would have had the effect of preventing well under 1 C of the projected temperature rise. The costs run to the trillions.
That’s not good policy. Prudent policy would try to understand what is going on before spending big money to change the entire economy.
JEP
The reply I got was:
This is a war of words that the creationists invented– if you keep repeating that “it’s just a theory” and “it’s just models,” the public will say oh, it’s not real. And I am afraid that the scientists are losing this war.
It’s something that non-scientists don’t quite understand: Science is all about models. When we scientists say “model,” what we mean is, this is our best understanding of the world. The fact that models get refined, and improved, is something that the creationists, and their ilk, attack as if it were a flaw, but it is, in fact, a feature of the scientific method, not a flaw.
What science is very, very good at is discriminating against competing models.  When scientists ask the so-called skeptics to come up with a viable model by which carbon dioxide in the atmosphere does NOT cause warming, this *is* the scientific method. Basically, by not having any good model by which the basic physics of the greenhouse effect can be circumvented, the skeptics have pretty much abandoned the idea of science, although they still maintain the pretense.
Of course it’s all about data. That’s what science does. That’s why science credits in the greenhouse effect, because the model fits the data.   (There are about 20,000 climate scientists in the world– do you seriously believe that none of them ever actually look at data?  What do you think they do?)
The greenhouse effect is very simple. The Earth emits infrared radiation. Greenhouse gasses in the atmosphere absorb this infrared radiation. They then re-emit the infrared in all directions. Some of the re-emitted infrared returns to the ground. This downwelling infrared radiation heats adds heat to the Earth.
Which part of this physics do you not credit?
If you don’t believe the model, you can take the data yourself. Find a LWIR spectrometer– a good university should have one– and measure the spectrum of the downwelling infrared radiation coming from the sky.  Then see if you can fit the data to a model that in which carbon dioxide does not cause global warming.
As far as I can tell, however, the climate-change “skeptics” have little interest in any data that does not fit their already pre-determined conclusions. *No* amount of data will ever change their opinions, because they will only pay attention to data if it fits their previously formed conclusions.
At which point I gave up since I learned nothing from the last reply, and it was getting clear that this renowned physicist wasn’t going to address my specific points. I have had similar dialogues with other AGW believers, but quoting them would make this already too long discussion even longer.
The part of the physics I don’t credit is that the predictions are that we should be seeing more temperature rise than we have observed. A second part of the physics I don’t credit is the accuracy of the measurements. I do not believe we know the temperature of the Earth in the time of Arrhenius to anything like a single degree of accuracy, and for that matter I am not convinced that we know it now to that accuracy. I don’t have any pre-determined conclusions. As an old Operations Research guy I do like to have some confidence in both theory and observations before I spend a lot of money on remedies to problems that are predicted by models.
I think I have been through all this several times.
Myself when young did eagerly frequent
Doctor and Saint, and heard great argument
About it and about: but evermore
Came out by the same door where in I went.
A longer version of this article is available here.
More at jerrypournelle.com.
