Archive for December 2011
I gave the sky dragons a platform, several threads in fact, it didn’t go very well for them as their arguments were debunked. The sky dragon group has been severely marginalized by those threads, which wouldn’t have happened if we followed your strategy.
– Judith Curry
When I have a technical post, there is generally some good albeit limited discussion, but comments invariably want to veer onto broader topics. The greenhouse effect remains of enduring interest. On some of the threads, physical chemists and molecular physicists showed up to provide their insights and clarify understanding. But these misconceptions remain in the dragonslayer group, although that group seems to be shrinking.
– Judith Curry
[T]he atmosphere does not act as a ‘blanket’ reducing the surface infrared cooling to space as maintained by the current GH theory, but is in and of itself a source of extra energy through pressure. This makes the GH effect a thermodynamic phenomenon, not a radiative one as presently assumed!
Together Equations (6) and (8) imply that the chemical composition of an atmosphere affects average air density through the molecular mass of air, but has no impact on the mean surface temperature.
Global surface temperature is independent of the down-welling LW flux known as greenhouse or back radiation, because both quantities derive from the same pool of atmospheric kinetic energy maintained by solar heating and air pressure.
– Ned Nikolov, Ph.D. & Karl Zeller, Ph.D.
“An excellent submission for peer 2 peer review”
“Uh-oh.. physics at last. Congratulations.”
“What a wonderful end-of-year present. Dr Nikolov has neatly and convincingly explained what others (e.g. ‘The Slayers’) have been broadly asserting for some time but without, in my opinion, providing an intelligible or convincing argument.”
“I applaud the efforts to help rectify physical inconsistencies in the current GH concept.”
“Nice update to the science debate.”
“Exciting times to live in and WUWT is in the lead in providing a sounding board for alternative ideas. Congratulations.”
“Thermodynamics of an ideal gas. The greenhouse effect is INDEPENDENT of the chemical composition of the atmosphere.
“Very good and understandable reasoning.”
“This is what I call a “killer” publication.
As the “Unified Theory of Climate” provides us with a great explanation how atmosphhic pressure determines our climate the principal AGW doctrine is completely destroyed by these conclusions”
“Could this be Game Set and Match?.
This is the most sensible theory I have heard to explain how the total atmosphere works.”
“If this pans out then Nobel Prizes (at least) are in order.”
“Although much of the math is beyond me, this looks to me like an entirely new climate paradigm and is a major game-changer!”
“It’s a very pretty poster. Visually balanced between the left and right sides, and colors are well thought out.”
“Thank you Drs Nikolov & Zeller for this real science. Well done.”
Fred, I reread the Huber/Knutti paper with the intention of starting a thread on this, but I really can’t see any merit or conclusions of interest here. It is a weak methodology that agrees with a bunch of previous studies, so there is no surprising result. I can do a post that tears the paper apart, but since I don’t think this is a very significant paper, i don’t think it is worth the effort?
– Judith Curry
Von Storch refers to Hulme’s analysis as “remarkable.” I agree. In fact I give this paper a “wow.” For those of you wondering when/why I give something a “wow,” it implies that the paper or whatever significantly changes the way I think about something. This does not necessarily imply a belief change, but it changes the way I think about a subject. What is a “wow” for me may not be relevant for someone else. This particular paper provides some important insights, and I really like the phrase and concept of “epistemic slippage.” This paper deserves to be widely discussed, and I look forward to interesting discussion here.
– Judith Curry
I just finished listening to Murry Salby’s podcast on Climate Change and Carbon. Wow. […] If Salby’s analysis holds up, this could revolutionize AGW science. […] While all this is frustratingly preliminary without publication, slides, etc., it is sufficiently important that we should start talking about these issues.
– Judith Curry
The 20th century aerosol forcing used in most of the AR4 model simulations (Section 188.8.131.52) relies on inverse calculations of aerosol optical properties to match climate model simulations with observations. […] Schwartz (2004) notes that the intermodel spread in modeled temperature trend expressed as a fractional standard deviation is much less than the corresponding spread in either model sensitivity or aerosol forcing, and this comparison does not consider differences in solar and volcanic forcing. This agreement is accomplished through inverse calculations, whereby modeling groups can select the forcing data set and model parameters that produces the best agreement with observations. While some modeling groups may have conducted bona fide forward calculations without any a posteriori selection of forcing data sets and model parameters to fit the 20th century time series of global surface temperature anomalies, the available documentation on each model’s tuning procedure and rationale for selecting particular forcing data sets is not generally available.
– J.A. Curry and P.J. Webster, “Climate Science and the Uncertainty Monster”
1) The authors claim that ‘The 20th century aerosol forcing used in most of the AR4 model simulations (Section 184.108.40.206) relies on inverse calculations of optical properties to match climate model simulations with observations’ and thus claim ‘apparent circular reasoning’. This is incorrect. The inverse estimates of aerosol forcing given in 220.127.116.11 are derived from observationally based analyses of temperature and are compared in Chapter 9 with “forward” estimates calculated directly from understanding of the emissions in order to determine whether the two are consistent. But it is critical to understand that such inverse estimates are an output of attribution analyses not an input, and thus the claim of ‘circular reasoning’ is wrong. The aerosol forcing used in 20C3M (see http://www-pcmdi.llnl.gov/projects/cmip/ann_20c3m.php) climate model simulations was based on forward calculations using emission data (Boucher and Pham, 2002; references in Randall et al., 2007). Further, detection and attribution methods determine whether model-simulated temporal and spatial patterns of change (referred to as ‘fingerprints’) that are expected in response to changes in external forcing are present in observations. For example, the aerosol fingerprint shows a spatial and temporal pattern of near-surface temperature changes that varies between hemispheres and over time (see Hegerl et al., 2007 section 18.104.22.168). […] These patterns make the response to solar and aerosol forcing distinguishable (with uncertainties) from that due to greenhouse gas forcing. The amplitude of those fingerprint patterns is estimated from observations. Therefore, attribution of the dominant role of greenhouse gases in the warming of the past half-century is not sensitive to the uncertainties in the magnitude of aerosol forcing, or of other forcings, such as solar forcing. […] Thus, Curry and Webster misrepresent the role of forcing magnitude uncertainties in attribution, and do not appreciate the level of rigour with which physically plausible alternative explanations of the recent climate change are explored.
– Gabriele Hegerl, Peter Stott, Susan Solomon and Francis Zwiers, “Comment on Climate Science and the Uncertainty Monster by J.A. Curry and P.J. Webster.”
Our overall concerns about the IPCC AR4 attribution statement and uncertainty analysis are best illustrated in the context of the recent publication by Gent et al. (2011), showing simulations of the 20th century climate of the NCAR Community Climate System Model Version 4. Figure 1 [the link downloads the file] compares the results of the CCSM3 (used in the AR4) with the CCSM4 simulations (for the AR5). In spite of using a better model and better forcing data for the CCSM4 simulations, the CCSM4 simulations show that after 1970, the simulated surface temperature increases faster than the data, so that by 2005 the model anomaly is 0.4oC larger than the observed anomaly. By contrast, the CCSM3 simulations show very good agreement with the surface temperature data. The critical difference is that the CCSM4 model was tuned for the pre-industrial period and used accepted best estimates of the forcing data, whereas the CCSM3 model was tuned to the 20th century observations and each modeling group was permitted to select their preferred forcing data sets. The contrast between the CCSM3 and CCSM4 simulations illustrate the bootstrapped plausibility of climate model simulations that influenced the AR4 attribution assessment.
– J. A. Curry and P.J. Webster, “Reply to Hegerl et al.’s Comment on “Climate Science and the Uncertainty Monster”” (draft)
Abstract. Hegerl et al.’s comment provides us with a further opportunity to emphasize and clarify our arguments as to why the treatment of uncertainty in the IPCC AR4 assessment regarding attribution is incomplete and arguably misleading.