I welcome critical reactions to my recent video, which I put together as a layman’s summary of the science of the skeptic’s position (if you have sent me criticisms, I have read them even if I have not gotten back to you — my real life has been crazy lately).
If you have not seen the video, and are a frequent reader of this site, I encourage you to do so. But to understand what follows, I need to share a bit of a summary of the video.
The video begins by accepting that CO2 acts as a greenhouse gas and that increased atmospheric concentrations can cause some incremental warming, on the order of magnitude of 1C per doubling of concentrations. But while I accept that CO2 causes incremental warming, I challenge the notion that there is a high climate sensitivity to CO2, driven by positive feedbacks, that multiply this warming to 3,5, even 10 degrees (thus the title of the video “Catastrophe Denied.”)
So, much of the video looks at alarmist arguments that sensitivity to CO2 is high, or in other words, that CO2 is acting as the main driver of world temperatures, that it is the dominant factor in recent temperature increases and its effect dwarfs all other effects.
In challenging this proposition, I took on 3 arguments:
- That ice core analysis (as shown by Al Gore in his movie) shows that for hundreds of thousands of years, CO2 and temperatures have moved together, demonstrating that CO2 is the main thermostat of the Earth
- That Michael Mann’s hockey stick (as given prominence by both the IPCC AR3 and AR4 as well as Al Gore in his movie, though incorrectly labeled as Dr Thompson’s Thermometer) shows that absent man, Earth’s temperatures were incredibly flat and stable and that only the introduction of manmade CO2 recently upset this stability
- That climate models are unable to replicate recent warming (ie in the last 50 years) using only natural forcings and only the introduction of CO2 into the models allows them to replicate history correctly
I am not going to deal with these arguments here (go watch the movie!) but several comments I have received are all of a single theme. Basically, the comments state that neither numbers 1 or 2 above are arguments any climate scientists are using and, further, just to demonstrate what a silly straw-man-erector I am, they were never used as proof of high climate sensitivity to CO2. This former may or may not be true, but the latter is just BS, and it represents a typical alarmist tactic. Make an argument, defend it like a mother bear (arguing skeptics are bad people for even questioning such obvious and settled science), and then when the argument finally gets shot down in flames, claim that it doesn’t matter and that it was never a serious argument anyway. The virtue of this tactic is not only that it can help paint skeptics as raising straw men, but it can also hide the fact that the science is so week that supporters must lurch from justification to justification, from thin limb to thin limb, trying to find a new branch of the tree to support them before the old branch breaks.
One commenter insisted to me, for example, that the ice core analysis from Al Gore’s movie was never meant to show a direct cause and effect relationship between CO2 and warming but to show proof of CO2 positive feedback (ie higher temps cause more CO2 to be driven out of the oceans which increases its concentration in the atmosphere which causes more warming). I have no doubt that is how it is used today, but it is just Stalinist revisionism to claim that this was Gore’s argument in the movie.
Steve McIntyre had an interesting example of this approach in a recent post (actually, Steve could write a book on the defend-defend-defend-defend-It doesn’t matter style of debate). For years, in response to questions about siting issues and uncorrected biases in the surface temperature record, James Hansen has claimed that the GISS has solved all that by using computer algorithms that compared sites to other nearby sites and used sophisticated statistical approaches (way beyond the ability of mere skeptics to understand) that corrected out all these biases. Some of us Luddites continued to argue that they weren’t correcting the biases in this homogenization approach, but were merely spreading the error around multiple stations like peanut butter (Anthony Watt has a lot more in his new book).
But then we find this from the FOI’e emails from the GISS:
The next morning (Aug 7), Ruedy sent Hansen and Gavin a draft reply to my email. He reported a US error of 0.15 deg C (a bit lower than my estimate the previous night.) The draft reply satirized the idea (then being promulgated by Rabett and Tamino) that GISS software could “fix” defects in surface data:
I had no idea what code you are referring to until I learned from your article “Hansen’s Y2K Error (which should really be Reto’s Y2K error) that GISS is in possession of some magical software that is able to “fix” the defects in surface data. No wonder you would like to get your hands on that – so would I. Unfortunately your source totally misled you in that respect. I’m a little amazed that you uncritically present it as a fact given that a large part of your web site is devoted to convincingly prove that such software cannot possibly exist.
And there is the technique in a nutshell, don’t just abandon the analysis when challenged, but deny it ever existed, and paint the challenger as somehow defective in his approach by “uncritically” suggesting such a straw man
This form of argument is a feature of all ideologues who have an agenda to promote and try to advance it through a tenuous link to some fabricated impending catastrophe.
Recent US politics gives a number of brazen examples: the TARP boondoggle, the “Stimulus” and socializing health care are all topical debates in which the same, or similar, techniques have been used ad nauseum.
In fact, the presence of this precise tactic is one of my leading litmus tests for sniffing out a hidden agenda in an argument, and for this reason I was an AGW skeptic long before I familiarized myself with some of the science. Many of the arguments either way are beyond my ken (I can follow the logic, but cannot judge whether factual relationships are necessarily as presented), but there is a clear pattern of slippery argumentation on the side of the AGW proponents that I have not been able to detect on the part of AGW opponents.
Regarding the ice-core temperature data graphs, typically the CO2 ranges from 180ppm to 280ppm. Temperature from -8 to +2 C – both figures approximate.
Assuming worst case sensitivity – derived from IPCC 2007 – temperature change due to CO2 would be
5.7 * ln(280/180) = 2.5C
So we can only assume that the remaining temperature change of 7.5C is unrelated to CO2. Or alternatively CO2 was at most responsible for 25% of the temperature change during ice-age transitions – and then with a lag of 800 or so years.
The warmist counter argument on CO2 lag is that it acts as an amplifier. But by the IPCC modeling it can only have amplified at most by 25%. And the IPCC modeling already includes a multiplier factor for CO2 of about 3.25 – presumably via changes in water vapor etc.
Based on the optical physics of CO2 alone, the ice-age CO2 contribution would be 2.5C / 3.25 = 0.76C or 7.6% of the observed change.
Warren,
Great video and I have a critique or two. (Being a critic is easy, you’ve really done a great job)
1. At one point you tell us that the Argo buoys haven’t shown any warming in the ocean, and somewhere else you tell us that historic sea level rise is due mainly to warming oceans. So are the oceans warming or not?
2. I do love your points about the Medieval Warm Period being a boon to European civilization and I think it ought to be stressed more. Indeed, it ought to be stressed that a warmer world would be a better world. Less ice and snow, longer growing seasons, more rain, more CO2 to enhance agriculture etc. Pro vs. con warmer is better, and you dealt with most negatives claimed for Global Warming already.
But what’s going to happen is world temperatures are going to go up again. I’d bet the farm on it, and when it does, you can take all your charts, graphs, analogies, smart remarks and take ’em out with last week’s rubbish, and Al Gore will be in the driver’s seat once again.
But the argument that a warmer world be a good thing will not be rubbish. Should public opinion regard a warmer world as a better world, all of Al Gore’s scare stories and hobgoblins won’t mean a thing and you won’t have to break a sweat updating your presentation.
Let me ask you this; where do most people go on vacation? Someplace warm or someplace cold?
And for those who tell you in response to the “warmer is better” argument that the tropics will burn up, remind them that the IPCC tells us that most of the warming will be in the winter time, night time and in the Arctic. Summer time, day time and in the tropics, not so much.
Thanks for reading
Steve Case
Brown Deer, WI
But we love the winters down here in the tropics.We hardly get any of the colder and more pleasant seasons.Please dont sell warmer winters and nights to those in the tropics -it is a horrible idea.
“I have no doubt that is how it is used today, but it is just Stalinist revisionism to claim that this was Gore’s argument in the movie.”
You might try looking up the same material in his movie-based book. I haven’t looked at it, but the phrasing may be more informative when trying to explain without the moving pictures.
“that the ice core analysis from Al Gore’s movie was never meant to show a direct cause and effect relationship between CO2 and warming but to show proof of CO2 positive feedback”
http://wattsupwiththat.com/2010/01/28/new-paper-in-nature-on-co2-amplification-its-less-than-we-thought/
“In this week’s Nature, David Frank and colleagues extend this empirical approach by comparing nine global-scale temperature reconstructions with CO2 data from three Antarctic ice cores over the period ad 1050-1800. The authors derive a likely range for the feedback strength of 1.7-21.4 p.p.m.v. CO2 per degree Celsius, with a median value of 7.7. The researchers conclude that the recent estimates of 40 p.p.m.v. CO2 per degree Celsius can be excluded with 95% confidence, suggesting significantly less amplification of current warming.”
There is a small predicted CO2 feedback. Somewhere between 5 and 50% of what IPCC thought….and surely no where near what Al Gore was trying to demonstrate.
What brother Al and others are guilty of is picking the worst case scenario’s from a number of poorly understood climate forcings and adding them all together. Pretty much anyone can create a disaster doing that.
Nice presentation. Thanks for that. You did not mention the absence of the famous hot spot, the AGW fingerprint. I find that a strong piece of falsifying evidence. But perhaps too complex for a laymen’s audience.
Furthermore, given the latest in temperature tweeking as described in the recent SPPI report, you might tone down your remarks on the reality of 20th century warming.
Anyway, mere detail, great work.
Ralf Dekker
Great summary (though occasionally a tad breathless …).
You asked for comments: your point on sea ice in terms of sea level rise is good, but the effect of losing the ice’s albedo is not addressed (and yes, it is partially, though not totally, offset by the growth of Antarctic sea ice).
Small issue, but if when you do the next version you might want to include it. (I also concur with Ralf’s point – while somewhat complex, it is visually easy to present, and it reinforces the problems with the models.)
The glacier point is really well done!
Great job, though!
“but it can also hide the fact that the science is so week that supporters must lurch from justification to justification, from thin limb to thin limb, trying to find a new branch of the tree to support them before the old branch breaks.”
Interesting, I have said virtually the same thing re: evolutionary theory (ies). Only I stated it as follows (here’s where it gets relevant):
It’s like Wile E Coyote staring down the RoadRunner. As the dust clears we see that the Coyote is standing on a rock suspended in mid air above a canyon. Coyote starts to run toward the Road Runner, only to find that each step is just on another rock, one that is just about to feel the influence of gravity.