Global Warming Man-Made, Will Continue

ABC News ^ | Feb 2, 2007 | SETH BORENSTEIN

[cogitator]

And apparently the Dust Bowl was a local phenomenon; your link mentions the connection between a cool tropical Pacific and droughts.

The 1930s were warm globally, though.

[cogitator]

Slightly tangentially, I was checking to see what RealClimate had to say about the IPCC SPM today, and found this:

Quick pre-SPM round up

"However, tucked away at the end was a rather confused section, where it appears that Lindzen bet Nye that ice cores don't have a resolution better than 2000 years. Now this is an odd claim, and an odder thing to bet on, since Greenland cores (GRIP, GISP2) and Antarctic cores (EPICA DML) have sub-annual resolution in many cases for the isotope (temperature) records, and at least decadal resolution (Law Dome, Siple Dome) for the greenhouse gases (CO2, CH4). It's true that the very longest records (Vostok and Dome-C) have coarser resolution, but surely Lindzen doesn't think they are the only ones that exist?"

Based on that, it would appear that some ice cores could provide data indicating 80-100 ppm CO2 excursions on the century scale -- if they ever happened. Note that this includes EPICA, the 650,000 year long core.

[cogitator]

This reversal means that seawater is absorbing a lot more anthro CO2 than I outlined in post 7.

OK, it should be. Thanks for checking.

[cogitator]

Sorry, I don't know (and don't have time to check right now) -- EPICA DML may not be the same as the EPICA 650,000 year long core.

I probably won't be able to reply again until late Monday; have a nice weekend.

[palmer]

It's true that the very longest records (Vostok and Dome-C) have coarser resolution, but surely Lindzen doesn't think they are the only ones that exist?"

The realclimate threads like this: http://www.realclimate.org/index.php?p=221 they always dance around the resolution issue. Your quote from them is a perfect example of the oft-repeated fallacy of juxtaposing high res records onto low res ones to make political points. Obviously their statement that CO2 is the highest in 650,000 years (the first major point in their report) is not supported by ice core evidence because, as Lindzen correctly points out, the old cores have 2k resolution in many cases. It's just the same old song and dance from them.

[ancient_geezer]

I have been in the field of science for some time now and I have not been aware of the term "very likely" translating to "more than 90% certainty."

It probably came from IPCC "Summary for Policymakers" footnotes, as it does for the Third Assessment Report.

specifically: http://www.grida.no/climate/ipcc_tar/wg1/fnspm.htm#7

"In this Summary for Policymakers and in the Technical Summary, the following words have been used where appropriate to indicate judgmental estimates of confidence: virtually certain (greater than 99% chance that a result is true); very likely (90-99% chance); likely (66-90% chance); medium likelihood (33-66% chance); unlikely (10-33% chance); very unlikely (1-10% chance); exceptionally unlikely (less than 1% chance). The reader is referred to individual chapters for more details."

UN/IPCC defines terms to suit their purposes. It definitely pays to check their footnotes and glossary of terms they put into their documents, their use of language is very deliberate and often leaves traps for the unwary, especially when they make statements as to uncertainty of an prognostication. Of course such usage just begs the question of how do they go about assessing the uncertainty to assign such phraseology.

In light of the very high probability that such assessements are essentially bayesian in character and assigning express percentages to such terms is very reminecent of what would come of applying the concepts expressed in this paper authored by Steven Schneider, (one of the historical heavy lifters in the anthropogenic global warming crew), I would say so:

http://stephenschneider.stanford.edu/Publications/PDF_Papers/UncertaintiesGuidanceFinal2.pdf

"A final note before turning to the specific recommendations themselves-the paper assumes that for most instances in the TAR, a "Bayesian" or "subjective" characterization of probability will be the most appropriate (see, e.g., Edwards, 1992, for a philosophical basis for Baysian methods; for applications of Bayesian methods, see e.g., Anderson, 1998; Howard et al., 1972). The Bayesian paradigm is a formal and rigorous language to communicate uncertainty. In it, a "prior" belief about a probability distribution (typically based on existing evidence) can be updated by new evidence, which causes a revision of the prior, producing a so-called "posterior" probability. Applying the paradigm in the assessment process involves combining individual authors' (and reviewers') Bayesian assessments of probability distributions and would lead to the following interpretation of probability statements: the probability of an event is the degree of belief that exists among lead authors and reviewers that the event will occur, given the observations, modeling results, and theory currently available. When complex systems are the topic, both prior and updated probability distributions usually contain a high degree of (informed) subjectivity. Thus in the TAR, we expect Bayesian approaches to be what is most often meant when probabilities are attached to outcomes with an inherent component of subjectivity or to an assessment of the state of the science from which confidence characterisations are offered."

And the intent of the use of such terms:

"It is certainly true that "science" itself strives for objective empirical information to test theory and models. But at the same time "science for policy" must be recognized as a different enterprise than "science" itself, since science for policy (e.g., Ravetz, 1986) involves being responsive to policymakers' needs for expert judgment at a particular time, given the information currently available, even if those judgments involve a considerable degree of subjectivity. "

 

[ancient_geezer]

P.S.

Mix polling & concensus politics with a the cloak of "science" one should not be surprised at what comes out of it. Add the knowledge that this is driven by general assembly UN politics at its core, the result is a foregone conclusion before the first draft report is it is even begun.

[avacado]

Thanks for both of those posts. That was very informative. So basically they have a way of giving an answer "on demand" to policy makers that is based on subjectivity.

[avacado]

This begs the question that if you have liked minded people on the belief of global warming then the variables are not random, and therefore, the result of certainty is contaminated?

[ancient_geezer]

In an an echo chamber, consensus is guaranteed.

The use of computer model output in such an environment, virtually to the point of giving it the status of empirical observation, becomes a particularly seductive and pernicious exercise in circular reasoning and self validation.

[palmer]

even if those judgments involve a considerable degree of subjectivity.

And apparantly it's ok to lie (withold that information). Thanks for your update. The real tragedy is not some stupid socialist carbon policy but the eventual shattering of public trust in science.

[ancient_geezer]

Speaking of models, here's an interesting assessment of the current ensemble of global climate models selected for the upcoming IPCC fourth assessment report as they compare in their responses to step changes in CO2 doubling and the hypothesized 20% increase in atmospheric water vapor associated with that doubling.

Gives one a idea of the standard deviation of the distributions these assessments apply to. It is also useful to note what the real gorilla in atmospheric physics is and where it the atmosphere it each has the most weight.

 

Radiative forcing by well-mixed greenhouse gases:
Estimates from climate models in the
Intergovernmental Panel on Climate Change
(IPCC) Fourth Assessment Report (AR4)
http://www.agu.org/pubs/crossref/2006.../2005JD006713.shtml

Collins, W.D., V. Ramaswamy, M.D. Schwarzkopf, Y. Sun, R.W. Portmann, Q. Fu, S.E.B. Casanova, J.-L. Dufresne, D.W. Fillmore, P.M.D. Forster, V.Y. Galin, L.K. Gohar, W.J. Ingram, D.P. Kratz, M.-P. Lefebvre, J. Li, P. Marquet, V. Oinas, Y. Tsushima, T. Uchiyama, and W.Y. Zhong 2006. Radiative forcing by well-mixed greenhouse gases: Estimates from climate models in the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4). J. Geophys. Res. 111, D14317, doi:10.1029/2005JD006713.

The radiative effects from increased concentrations of well-mixed greenhouse gases (WMGHGs) represent the most significant and best understood anthropogenic forcing of the climate system. The most comprehensive tools for simulating past and future climates influenced by WMGHGs are fully coupled atmosphere-ocean general circulation models (AOGCMs). Because of the importance of WMGHGs as forcing agents it is essential that AOGCMs compute the radiative forcing by these gases as accurately as possible. We present the results of a radiative transfer model intercomparison between the forcings computed by the radiative parameterizations of AOGCMs and by benchmark line-by-line (LBL) codes. The comparison is focused on forcing by CO₂, CH₄, N₂O, CFC-11, CFC-12, and the increased H₂O expected in warmer climates. The models included in the intercomparison include several LBL codes and most of the global models submitted to the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4). In general, the LBL models are in excellent agreement with each other. However, in many cases, there are substantial discrepancies among the AOGCMs and between the AOGCMs and LBL codes. In some cases this is because the AOGCMs neglect particular absorbers, in particular the near-infrared effects of CH₄ and N₂O, while in others it is due to the methods for modeling the radiative processes. The biases in the AOGCM forcings are generally largest at the surface level. We quantify these differences and discuss the implications for interpreting variations in forcing and response across the multimodel ensemble of AOGCM simulations assembled for the IPCC AR4.

*** SNIP ***

[12] The specifications for each of the calculations requested from the LBL and AOGCM groups are given in Table 1. The concentrations of WMGHGs in calculations 3a and 3b correspond to conditions in the years 1860 AD and 2000 AD, respectively. The concentrations in 1860 are obtained from a variety of sources detailed in IPCC [2001]. Differences among these calculations cover several standard forcing scenarios performed by all AOGCMs in the AR4, including (1) forcing for changes in CO₂ concentrations from 1860 to 2000 values (case 2a-1a) and from 1860 to double 1860 values (case 2b-1a), (2) forcing for changes in WMGHGs from 1860 to 2000 values (case 3b-3a), and (3) the effect of increased H2O predicted when CO₂ is doubled (case 4a-2b). In addition to the four forcing experiments listed above, there are three additional forcing experiments for combinations of CH4, N2O, CFC-11, and CFC-12. The changes in WMGHGs and H2O in these seven forcing experiments are listed in Table 2.

*** SNIP ***

*** SNIP ***

[Fraxinus]

The real tragedy is not some stupid socialist carbon policy but the eventual shattering of public trust in science.

I very much agree. So much of the global warming BS is based on computer models. It has been warming for the duration of records (from 1850-1870), however there is very little known about climate and solar cycles greater than 11 years. There is some newer (last 5-10 years) information about climate cycles in the 30 year range, however, It seems that supporters of global warming refuse to admit to the possibility of climate and solar cycles that are hinted at with periods of 1500+ years. Do land use changes by man in the past century affect climate? Most definitely. Is man causing global warming? Not as certain.

[ancient_geezer]

It seems that supporters of global warming refuse to admit to the possibility of climate and solar cycles that are hinted at with periods of 1500+ years.

That is probably the understatement of the year.

The following is typical of input data for modeling solar irradiation with regards projection runs (in the particular NASA's http://data.giss.nasa.gov/modelE/ ).

Note the lack of long term variation in solar component after 2000. No attempt is made to take even the well known 80-year Gleissberg or 200-year Suess solar cycles into account in projections the longterm solar irradiation is assumed constant with only a fixed period/magnitude sunspot cycle.

Data @ NASA GISS Earth's Energy Imbalance Simulations

Data @ NASA GISS Forcings in GISS Climate Model

Data @ NASA GISS Forcings in GISS Climate Model Solar Iradiance:

 

This figure summarizes data obtained from Judith Lean and used in GISS GCM runs.

postscript (154 kb), README, tabular data (420 kb)

Instantaneous forcing was computed continuously from 1850 to 2000 using Model E with 16 layers.

tabular data (2 kb), postscript (35 kb) postscript, 1850 to 2000 (35 kb)

[ancient_geezer]

Of course one might also wonder how such a low long term solar variation comes about.

When one makes aprior assumptions about the contribution of solar variation to change in global temperature since the Maunder minimum, selecting a dataset to fit a CO2 driven hypothesis becomes a snap.

Data archives are so illuminating when one digs around in them abit:

Index of -pub-data-paleo-climate_forcing-solar_variability

http://www1.ncdc.noaa.gov/pub/data/paleo/climate_forcing/solar_variability/bard_irradiance.txt

2. Data from Figure 3. Reconstructed Solar Irradiance Scaled against Maunder Minimum Total Solar Irradiance reductions of

• 0.25% (Lean et al. 1995),
• 0.40% (Zhang et al. 1994,
• Solanki and Fligge, 1998)
• 0.55% (Cliver et al. 1998), and
• 0.65% (Reid 1997)