For the record, I linked to those sources more of as a tease. I thought you'd realise that you keep making arguments by referring to secondary sources. Let's keep this scientific and use primary sources only, okay? Similarly, third party refutations of third party refutations are... well... I think you see the problem, and it begins with an H.
As for the sourcewatch, I don't see how they specifically refute what I was referring to. They also don't give a very detailed background information, and is all cherry picked info and just a sentence or two on each topic. How can a sentence sufficiently reply to a book length study? It doesn't mention Spencer's awards and commendations by NASA or the Nat. Meterological Assoc., and seems to try to downplay the fact that he's an IPCC contributor and lead author on UN reports. He has hundreds of peer reviewed articles in journals such as Science and Nature and yearly sits on climate change panels, and has testified over a dozen times in the US House and Senate. The presence of one's name on such a biased website is more a testament to the fear of actual argumentation by distinguished and well cited scientists than a refutation of any claims made by the individuals. Also, if you look at the citations you'll have a laugh - they just refer to other secondary and tertiary sources. So let's just focus on the facts okay?
Kim O'Hara wrote:
Here's something which is highly relevant to those points and to your Feynman quote. Please read it. It finishes thus:
“To conclude, a projection from 1981 for rising temperatures in a major science journal, at a time that the temperature rise was not yet obvious in the observations, has been found to agree well with the observations since then, underestimating the observed trend by about 30%, and easily beating naive predictions of no-change or a linear continuation of trends. It is also a nice example of a statement based on theory that could be falsified and up to now has withstood the test. The “global warming hypothesis” has been developed according to the principles of sound science.”
There’s a more technical discussion of the same paper at http://skepticalscience.com/lessons-from-past-predictions-hansen-1981.html
if that isn’t enough.
See it all at http://www.realclimate.org/index.php/archives/2012/04/evaluating-a-1981-temperature-projection/
Well, as you will probably know Hansen actually dropped this model in 1988. But to give you the benefit of the doubt, so I had a look at the article on JSTOR. It's actually quite cute how he thought we could phase out fossil fuels by 2000. I wonder whether the review you posted bothered to read the article at all.
His low-range prediction was a 0.3C increase by 2010. But averages from satellite and balloon data show that we have had a 0.22C increase (Jansen et al., Ch. 6, Palaeoclimate, Section 220.127.116.11: What Do Reconstructions Based on Palaeoclimatic Proxies Show?, pp. 466–478, in IPCC AR4 WG1 2007) (Goddard Institute Surface Temperature Analysis (GISTEMP)) (GISTEMP 2011 Analysis: Global Temperature, Trends, and Prospects). Which disproves the main thesis, that "the anthropogenic carbon dioxide warming should emerge from the noise level of natural climate variability by the end of the century." (957)
Note that the key isn't at all anything to do with predicted temperature rises or models, but the question of whether CO2 "causes" a rise in temperature in the real atmosphere. The assumptions on how this works are found if you follow citation 6 to: National Academy of Sciences, Carbon Dioxide and Climate: A Scientific Assessment (Washington, D.C., 1979). There you will see the source of the first claims about the 2-3.5C increases at surface temperature, with greater increases at high latitudes, due to CO2. You will also see that the argument is based upon these premises: that 50% of CO2 emissions in 1979 are man made,that temperature increases are due to CO2 emissions, the CO2 increase is manmade (since 1800s levels were 290ppm and now they are 334ppm), and that cloud coverage will not vitiate the predictions.
For the 1st claim, it's quite funny, but maybe reliant upon old data. Of course, we assume to know how much CO2 was produced in the 19th century based upon the increase. According to David J. C. MacKay, Sustainable Energy —Without the Hot Air (Cambridge: UIT, 2008), the burning of fossil fuels sends seven gigatons (3.27 percent) of carbon dioxide into the atmosphere each year, while the biosphere and oceans account for 440 (55.28 percent) and 330 (41.46 percent). So, the roughly 45% increase in ppm since 1800 is probably due to natural causes. This explanation is consistent with ice core data from 1980-2011, as per Global and Planetary Change, Volume 100, January 2013, Pages 51–69. "Ice cores show atmospheric CO2 variations to lag behind atmospheric temperature changes on a century to millennium scale, but modern temperature is expected to lag changes in atmospheric CO2, as the atmospheric temperature increase since about 1975 generally is assumed to be caused by the modern increase in CO2. ... The maximum positive correlation between CO2 and temperature is found for CO2 lagging 11–12 months in relation to global sea surface temperature, 9.5-10 months to global surface air temperature, and about 9 months to global lower troposphere temperature."
As for the cloud coverage claim, they do, to be fair, evaluate quite even handedly the data they had at the time in 1979 - which was almost nothing. But despite admitting possible negative feedback, and that "the modeling of clouds is one of the weakest links in the general circulation modeling efforts," they now have that data. (JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 115, D16109, doi:10.1029/2009JD013371, 2010)
As for the Hanson 1988 model, it doesn't differ immensely from 1981, he lowers his lowest estimate to 0.29, and gives a wild high estimate of 0.9. What more do I need to say? Temperatures showed a natural deviation from CO2 levels. (Dr. Pieter Tans, NOAA/ESRL and Dr. Ralph Keeling, Scripps Institution of Oceanography (scrippsco2.ucsd.edu/).) CO2 has increased at a constant rate.
Kim O'Hara wrote:
Global temperature has in recent years increased more slowly than before, but this is within the normal natural variability that always exists, and also within the range of predictions by climate models – even despite some cool forcing factors such as the deep solar minimum not included in the models. There is therefore no reason to find the models faulty. There is also no reason to expect less warming in the future – in fact, perhaps rather the opposite as the climate system will catch up again due its natural oscillations, e.g. when the Pacific decadal oscillation swings back to its warm phase. Even now global temperatures are very high again – in the GISS data, with an anomaly of + 0.77 °C November was warmer than the previous record year of 2010 (+ 0.67 °), and it was the warmest November on record since 1880.
ZL wrote:Just for the record, since it was overlooked by repliers, my argument depends on assumptions made about the effects of feedbacks, such as how increased cloud coverage influences temperatures.
Just for the record, you're shifting ground by saying that. It isn't very long since you said,
Where I differ [from AGW believers] is that I don't believe in treating CO2 as a problem.
Not that I mind, so long as you're shifting towards a more accurate perception.
Firstly, 30 year monthly GISS anomalies have an average of 0.22. I am not sure why AGW proponents do exactly what they don't like to hear in opponents. Whenever there's a hot anomaly, they claim it's global warming, but whenever AGW opponents claim that a cold anomaly is a contradiction to global warming they say that they don't understand the fact that global warming is an average trend. Well, AGW opponents only do that to tease AGW proponents about this -- just take 1998 for instance. How many times have in 1998 did you hear the AGW proponents take this as their proof? Of course, having a warmest year on record means nothing for the AGW case. I will argue in averages, if you argue in averages too.
As for the absence of the deep solar minimum in the models, yes, granted. But I think you know well that it's unscientific to say that there's "no reason to find the models faulty." And also, "There is also no reason to expect less warming in the future." I thought this was science? Shouldn't we say "let's wait and see?" if it is a matter of evaluating a model that one is claiming will balance back out? Of course, I don't blame them for this. Everyone wants to make their argument look more believable.
As for not treating CO2 as a problem, I don't see how this is a shifting position. This is based on my conclusion. Don't mistake conclusion for the theory. We can talk more about conclusions another time, but CO2 shouldn't be treated as a problem, it's beneficial as a whole to life on earth to have more CO2 - but we really don't have the power to increase it significantly.
Kim O'Hara wrote:As for feedbacks, they are addressed in the overview I have just referred you to. In support of your (new) position, yes they are an area of uncertainty. On the other hand, the limits of the uncertainty are such that no conceivable combination of cooling feedbacks is strong enough to counterbalance the CO2-driven warming.
I think this opinion is dealt with sufficiently in what I have written before. Perhaps you misunderstand 'how' they calculate what the feedbacks are.