What Do We Think About Climate Change

[Jimbo1490]

Thomas,

Go to the Christy lecture on Youtube, and fast forward to 21:00. There he explains the corresponding negative feedback. First, he acknowledges the positive feedback of water vapor and CO2 concentrations you pointed out in your citation. He then explains the negative feedback which results, which is that cloud albedo changes, reducing the radiative budget more than the resulting greenhouse feedback increases it. It's described in a paper by Roy Spencer, et al. I mentioned the existence of this same feedback mechanism about 25 pages back in the thread, but I did not link to the paper at that time.

Jimbo

[Jimbo1490]

Excerpted from the paper cited above:

[21] "The composite of fifteen strong intraseasonal oscillations
we examined revealed that enhanced radiative cooling
of the ocean-atmosphere system occurs during the
tropospheric warm phase of the oscillation. Our measured
sensitivity of total (SW + LW) cloud radiative forcing to
tropospheric temperature is 6.1 W m2 K1. During the
composite oscillation’s rainy, tropospheric warming phase,
the longwave flux anomalies unexpectedly transitioned
from warming to cooling, behavior which was traced to a
decrease in ice cloud coverage. This decrease in ice cloud
coverage is nominally supportive of Lindzen’s ‘‘infrared
iris’’ hypothesis. While the time scales addressed here are
short and not necessarily indicative of climate time scales, it
must be remembered that all moist convective adjustment
occurs on short time scales. Since these intraseasonal
oscillations represent a dominant mode of convective variability
in the tropical troposphere, their behavior should be
considered when testing the convective and cloud parameterizations
in climate models that are used to predict global
warming."


Jimbo

[Boston]

the official view of the American Physical Society
http://www.google.com/url?q=http://w...dIzxgI5agn6XxQ

Emissions of greenhouse gases from human activities are changing the atmosphere in ways that affect the Earth's climate. Greenhouse gases include carbon dioxide as well as methane, nitrous oxide and other gases. They are emitted from fossil fuel combustion and a range of industrial and agricultural processes.
The evidence is incontrovertible: Global warming is occurring. If no mitigating actions are taken, significant disruptions in the Earth’s physical and ecological systems, social systems, security and human health are likely to occur. We must reduce emissions of greenhouse gases beginning now.
Because the complexity of the climate makes accurate prediction difficult, the APS urges an enhanced effort to understand the effects of human activity on the Earth’s climate, and to provide the technological options for meeting the climate challenge in the near and longer terms. The APS also urges governments, universities, national laboratories and its membership to support policies and actions that will reduce the emission of greenhouse gases.

[Boston]

seems like a few of you aren't listening no mater what gets said or who says it
we have been over this hole Christy thing and it only flies with the agnotologysts

The truth is that even John Christy no longer believes the claims that he once made, and that desperate Republicans still bring him out of the closet to defend their energy policies. As more evidence has accumulated, Christy has conceded that global climate change is happening. Christy has also conceded that global climate change is at least to some degree due to human activity, saying, "It is scientifically inconceivable that after changing forests into cities, turning millions of acres into farmland, putting massive quantities of soot and dust into the atmosphere and sending quantities of greenhouse gases into the air, that the natural course of climate change hasn't been increased in the past century."

First, he denied that global climate change is really taking place. Then, he had to admit that global climate change exists, and so denied that the observed global climate change was the result of human activity. Now, it seems, he has abandoned that position too. At present, Christy's position is merely that global climate change will not be catastrophic.

[Jimbo1490]

One of the supporting papers:

http://www.cdc.noaa.gov/people/dezhe...JC-revised.pdf

An excerpt:

"ABSTRACT:

By comparing the response of clouds and water vapor to ENSO forcing in nature with that in AMIP
simulations by some leading climate models, an earlier evaluation of tropical cloud and water vapor
feedbacks has revealed two common biases in the models: (1) an underestimate of the strength of
the negative cloud albedo feedback and (2) an overestimate of the positive feedback from the
greenhouse effect of water vapor. Extending the same analysis to the fully coupled simulations of
these models as well as other IPCC coupled models, we find that these two biases persist. Relative
to the earlier estimates from AMIP simulations, the overestimate of the positive feedback from
water vapor is alleviated somewhat for most of the coupled simulations."

Jimbo

[Jimbo1490]

And another:

http://www.ecd.bnl.gov/steve/pubs/HeatCapacity.pdf

An excerpt:

"(3) The low equilibrium climate sensitivity λs
-1 inferred from (1) and (2) as λ τ s
− = 1 /C, 0.30 ± 0.14 K/(W
m-2), equivalent to equilibrium temperature increase for doubled CO2 ∆T2× = 1.1 ± 0.5 K. This value is
well below current best estimates of this quantity, summarized in the Fourth Assessment Report of the
IPCC [2007] to be "2 to 4.5 K with a best estimate of about 3 K and ... very unlikely to be less than 1.5
K"."

Jimbo

[Jimbo1490]

From this website:

http://ff.org/centers/csspp/library/...-15/trends.htm

"Dahl-Jensen et al. (1998) used temperature measurements from two Greenland Ice Sheet boreholes to reconstruct the surface temperature history of the ice sheet over the past 50,000 years. The data revealed that temperatures there during the Last Glacial Maximum approximately 25,000 years ago were 23 ± 2 °C colder than at present. After the termination of the glacial period, however, they rose to a maximum of 2.5°C warmer than at present, during the Holocene Climatic Optimum of 4,000 to 7,000 years ago. The Medieval Warm Period and the Little Ice Age were also documented in the record, with temperatures 1°C warmer and 0.5-0.7°C colder than at present, respectively. Finally, after the end of the Little Ice Age, they report that "temperatures reached a maximum around 1930," but that they "have decreased during the last decades." All of these observations clash with the hockeystick temperature history of Mann et al. (1998, 1999), which is used by the IPCC to make it appear that the Medieval Warm Period and Little Ice Age were mere fables and that 20th-century warming "during the last decades" was unprecedented over the past one to two millennia and caused by anthropogenic CO2 emissions."

Full text of the Dahl-Jensen paper is not available online (for free ) anymore.

Jimbo

[Landlubber]

The original do gooder claim was not Climate Change, it was Global Warming, this then went to Global Cooling, and because that did not work either, it was Global Climate Change......well of course the climate changes, people have been talking about the weather since we could first speak!
And of course people must have some alteration to this Climate Change, just how much....well that is yet to be decided, but when i fly iver the Indonesian Islands and see the volcano eruptions with black smoke clouds as far as we can see, it seem to me that Mother Nature may just do more to the big blue marble than all of us put together............

[Jimbo1490]

Excerpted from here:

"The additional anthropogenic greenhouse gases that have been introduced into the atmosphere increase the IR energy absorbed by the atmosphere, thereby exerting a warming influence on the lower atmosphere and the surface, and a cooling influence on the stratosphere [Peixoto and Oort, 1992; Ramanathan et al., 1985]."

Thomas,

Note that this directly contradicts Mann's explanation/prediction at realclimate.org of why Beer-Lambert does not apply to atmospheric CO2 concentrations on planet Earth. We can't have it both ways at once, now can we?

And again the question is asked, "where, oh where can be found the tropical tropospheric warming?"

If the feedback Christy makes a case for does not exist, then the tropical troposphere is exactly where the anomalous heating will occur, after all.

Jimbo

[Boston]

exerpts from Judge William Sessions III decision in which Christy testified for the automakers

There is widespread acceptance of the basic premises that underlie Hansen’s testimony. Plaintiffs’ own expert, Dr. Christy, agrees with the IPCC’s assessment that in the light of new evidence and taking into account remaining uncertainties, most of the observed warming over the last fifty years is likely to have been due to the increase in GHG concentrations. Tr. vol. 14-A, 145:18-148:7 (Christy, May 4, 2007). Christy agrees that the increase in carbon dioxide is real and primarily due to the burning of fossil fuels, which changes the radiated balance of the atmosphere and has an impact on the planet’s surface temperature toward a warming rate. Id. at 168:11-169:10.

Christy also agreed that climate is a nonlinear system, that is, that its responses to forcings may be disproportionate, and rapid changes would be more difficult for human beings and other species to adapt to than more gradual changes. Id. at 175:2-174:11. He further agreed with Hansen that the regulation’s effect on radiative forcing will be proportional to the amount of emissions reductions, and that any level of emissions reductions will have at least some effect on the radiative forcing of the climate.

Christy criticized the Hadley and Canadian models, suggesting that they were extreme and were downscaled unreliably. Tr. vol. 14-A, 121:13-122:4 (Christy, May 4, 2007). Although Christy testified that he had used climate models, however, he did not claim to be an expert on climate modeling. Id. at 78:20-79:3. In fact, his view of the reliability of climate models does not fall within the mainstream of climate scientists; his view is that models are, in general, “scientifically crude at best,” although they are used regularly by most climate scientists and he himself used the compiled results of a variety of climate models in preparing his report and testimony in this case.

John Christy's testimony

A “forcing” is an imposed perturbation to the planet’s energy balance, measured in watts per meter squared. Greenhouse gases absorb heat radiation, so that an increase in the amount of these gases in the atmosphere is a mechanism for making the Earth’s surface warmer. Such warming can be measured in the same way as other causes of temperature change, such as changes in the sun’s brightness.

Since pre-industrial times, there has been a drastic increase in atmospheric concentrations of such gases, due primarily to fossil fuel burning.

The concentration of carbon dioxide in the ambient atmosphere in the present time, averaged over the world, is about 383 parts per million, compared with 280 parts per million in the pre-industrial era. This increase is due primarily to fossil fuel burning, which accounts for about eighty percent of the increase. To find carbon dioxide concentrations as high as current ones, it is necessary to look at a period two to five million years ago. Current annual increases in carbon dioxide emissions are two parts per million, up from one part per million when measurements began in 1958. They are predicted to rise to about four parts per million per year by the middle of the century under the business-as-usual scenarios of such gases, due primarily to fossil fuel burning.

for a complete transcript of the court records
http://www.columbia.edu/~jeh1/vermont_decision.pdf
were I think you will find pg 38 through 47 of particular interest
I would note that the Judges notes are also of particular interest

have a great night
B

body slam

[Meanz Beanz]

Originally Posted by Landlubber

The original do gooder claim was not Climate Change, it was Global Warming, this then went to Global Cooling, and because that did not work either, it was Global Climate Change......well of course the climate changes, people have been talking about the weather since we could first speak!

Have you heard "Climate Kaos" yet?

[Boston]

that was kinda funny
the real funny is that none of the detractors seem to even know what the real moniker is

it being repeatedly misstated as Global Warming

which is sooooo behind the times

its Rapid Global Climate Change trimmed down to Climate Change

have a field day

Agent 86
out

[Guillermo]

Jim et al.:
Have a look at this interesting work from Zbigniew Jaworowski, M.D., Ph.D., D.Sc., on the CCSP-USP Report, august 2008. Specially have a look at his comments on the lack of reliability from ice core CO2 data. (Dr. Jaworowski measured the concentration of CO2 in the atmospheric air at Spitsbergen and investigated the history of the pollution of the global atmosphere, measuring the dust preserved in 17 glaciers: in the Tatra Mountains in Poland, in the Arctic, Antarctic, Alaska, Norway, the Alps, the Himalayas, the Ruwenzori Mountains in Uganda, and the Peruvian Andes.)

http://www.21stcenturysciencetech.co...ate_Report.pdf

From there:
The foundations of the CCSP-USP Report, its “fingerprints” and “human influences,” are based on ice core studies of CO2. However, ice cores are a wrong matrix for reconstruction of chemical composition of the ancient atmosphere. No effort dedicated to improving analytical techniques can change the imperative pattern of polar ice as a non-closed system matrix. Because of this pattern of ice, the CO2 ice core data will always be artifacts caused by processes in the ice sheets and in the ice cores, with CO2 concentration values about 30% to 50% lower than in the original atmosphere.
The low CO2 ice-core concentrations during thepast interglacials, when the global temperature was warmer than now, suggest that either atmospheric CO2 levels have no discernible influence on climate, or that proxy ice core reconstructions of the chemical composition composition of the ancient atmosphere are false. Both propositions are probably true.
The scenarios in the CCSP-USP Draft Report are based on unreliable ice core data and on an incorrect presentation of the past climatic changes. They should not be used for global economic planning. Under the Information Quality Act’s terms, this document is not permissibly disseminated so long as it continues to reproduce
these false scenarios with the apparent imprimatur of the Federal government.
The requested changes are:
(1) to drop all the references to “human influences” and “fingerprints,” as they cannot be credibly validated and are in fact empty notions;
(2) to present the veritable fluctuation of climatic cold and warm phases over the past millennium;
(3) to review the recent cosmo-climatologic studies, and to reflect them in the conclusions and recommendations of the Report.
Without such corrections, the statements in this document fail to meet the authors’ claim of representing “the best available information” (p. 14), and “the best available evidence” (p. 15), and otherwise violate applicable objectivity requirements.


Cheers.

[bntii]

It's revealing to see how main stream skeptics address Jaworowski:

Steve McIntyre:
August 9th, 2006 at 2:24 pm
Out of all the issues to deal with CO2 measurements in ice cores are not something that particularly worry me and I do not believe that this evidence is "more shaky" than tree rings.

Posters keep bringing him up so need to be reminded....

• Beck and Jaworowski are ignored for cause. They are outer fringe and as a result cannot be discussed here by site rule. Citation of them as reliable sources means you cannot be taken seriously either.

Steve McIntyre:
October 7th, 2008 at 8:40 am
James G, this blog is about mainstream papers relied upon by IPCC. I've asked people not to discuss Beck and Jaworski here as, in my opinion, any issues that they may have raised have been adequately answered. I'm not interested in intervening myself into this sort of topic. But if I don't, this is interpreted elsewhere as acquiescence. So editorially I ask that you take this topic to some other venue.

"James, as Steve says, discussions on Beck and Jaworowski don't belong here. This is a serious blog on scientific matters."

"Jaworowski is a handwaving contrarian who is suggesting all sorts of errors in the ice cores but doesn't give any evidence that all these errors do really occur."

"As someone with long forgotten science training I was nearly taken in by Jaworowski. Can't say what it was that had my alarm bells ringing, but ringing they were. Wow, what a disservice to honorable skepticism."

"There are some results in the literature that are outrageously wrongheaded (for example Beck's trawling for old CO2 data, and the claim that humans are responsible for only 0.0000002% of CO2 emissions over GEOLOGICAL time) that one might suspect that they were planted by "the team" to discredit the skeptical movement.
Jaworowski falls for all of these, and adds a huge dose of paranoia, revealing that he lacks scientific judgment, and his skepticism is entirely one sided. At best he may have identified some second or third order effects in ice core gas concentrations, but discussion of these is mixed with egregious misunderstandings of the ice core data."

"Segalstad is a coauthor of Jaworowski, and the only thing either have proven is that you can find some scientist somewhere who will say just about anything."

[Jimbo1490]

Jaworowski's work is certainly interesting, but seems to lack sufficient stature at this time to call into serious question the provenance of nascent atmospheric CO2.

Christy's work, however, on the corresponding negative feedback, which arises from and more than offsets the positive feedback of CO2 with water vapor, does hold up, confirmed by (or confirming) Lindzen's 'Iris Effect'. As in any regulated system, there are still fluctuations around the 'set point' but these are not 'perturbations', per se. The fluctuations in a regulated system are not 'slop' or hysteresis either; that is something different. Rather it should be thought of as 'droop', a sort of proportionate 'micro response' to the stimulus, which would be much larger and unable to return to the un-perturbed state without the mitigating factor of the regulatory mechanism in place.

It also seems confirmed by the lack of warming in the tropics, and the overall lower observed climate sensitivity. The IPCC seems to consistently predict a climate sensitivity that is roughly double the actual observed sensitivity. This big negative feedback is missing from their GCM's which explains this discrepancy nicely.

Jimbo