Thin Polar Bears Called Sign of Global Warming

Environmental News Service ^ | 05/16/2002

[cogitator]

Thin Polar Bears Called Sign of Global Warming

WASHINGTON, DC, May 16, 2002 (ENS) - Hungry polar bears are one of the early signs that global warming is impacting Arctic habitat, suggests a new study from World Wildlife Fund. The report reviews the threats faced by the world's 22,000 polar bears and highlights growing evidence that human induced climate change is the number one long term threat to the survival of the world's largest land based carnivores.

Global warming threatens to destroy critical polar bear habitat, charges the report, "Polar Bears at Risk." The burning of coal and other fuels emits carbon dioxide (CO2) and other gases that blanket the earth, trap in heat and cause global warming.

According to the Intergovernmental Panel on Climate Change (IPCC), climate change in the polar region is expected to be the greatest of anywhere on Earth.

"The WWF report shows that polar bears in Hudson Bay are being impacted by climate change," said Lynn Rosentrater, coauthor of the report and climate scientist at the World Wildlife Fund's (WWF) Arctic program. "The polar bear's basis for survival is being threatened by the reduction of the sea ice."

"Since the sea ice is melting earlier in the spring, polar bears move to land earlier without having developed as much fat reserves to survive the ice free season," Rosentrater explained. "They are skinny bears by the end of summer, which in the worst case can affect their ability to reproduce."

Increasing CO2 emissions have caused Arctic temperatures to rise by five degrees Celsius over the past 100 years, and the extent of sea ice has decreased by six percent over the past 20 years. By around 2050, scientists now predict a 60 percent loss of summer sea ice, which would more than double the summer ice free season from 60 to 150 days.

Sea ice is critical to polar bears' survival because it is the platform from where they hunt their primary prey - ringed seals and bearded seals. Diminishing ice cover and longer ice free periods limit the time the bears have on the ice to hunt and means that they have fewer fat resources to survive during the longer summer season.

Lower body weight also reduces female bears' ability to lactate, leading to fewer surviving cubs. Already, fewer than 44 percent of cubs now survive the ice free season.

As early as 1999, Canadian researchers noticed that polar bears in the Hudson Bay region were having trouble finding enough seals to eat due to the earlier breakup of sea ice. The scientists from the Canadian Wildlife Service found that weight for both male and female polar bears was declining, and female bears were having fewer cubs.

The impacts of global warming come on top of problems that polar bears already face from hunting, toxic pollution and oil development in the Arctic. The Arctic region is contaminated by pesticides and other chemicals carried by air and condensation from industrialized areas far to the south.

The pollutants enter the food chain, and animals at the top of the chain, such as polar bears, can carry tremendous body burdens of toxic chemicals. Research on polar bears has shown a link between high contaminant levels and reduced immune system function.

Due to the rapid pace of change in the Arctic, there is no time to lose in reducing emissions of greenhouse gases, WWF argues. The group says major reductions can be achieved by using existing technologies to increase the energy efficiency of homes, businesses and automobiles, and by using renewable energy sources instead of fossil fuels.

Bipartisan support has grown in Congress for a renewable portfolio standard that would ensure that 20 percent of U.S. energy comes from renewable energy by 2020. However, President George W. Bush has opposed the proposal.

World leaders will discuss a similar proposal at the World Summit for Sustainable Development in South Africa this summer. The WWF is calling on President Bush to support this initiative in Johannesburg.

"Arctic nations that are home to most of the world's polar bears should be leading the charge against global warming," said Jennifer Morgan, director of WWF's climate change program. "Instead, the United States - the world's largest global warming polluter - is essentially ignoring this problem. All eyes will be on President Bush at the upcoming World Summit on Sustainable Development in South Africa this August to test his commitment to sustainable energy solutions for climate change."

The WWF has created a new Web site: http://www.panda.org/polarbears with extensive information about polar bears and their Arctic domain. The site includes satellite tracking of two female bears, Louise and Gro, as they roam the ice pack in search of prey.

[Rita289]

Thin Polar Bears Called Sign of Global Warming.

Maybe it's all that Diet Pepsi.

[ancient_geezer]

But you need a mechanism for cooling.

Albedo(clouds & dust),

IR irradiation from surface absorbed in 1st hundred feet of atmosphere where it is predominately dissipated as kinetic energy.

Transport of heat from the surface to the upper atmosphere by convection dominated by

• N2 & H2 kinetic energy &
• watervapor(latent heat of vaporization/sublimation)

released radiant energy to stratosphere and on into space.

downward directed re-radiant IR is absorbed in the upper region of the atmosphere dissappated as kinetic energy not returning to the surface except by convection of cold air.

The role of CO2 is minimal by virtue of the near total absorption of IR in a very short path of troposphere. Adding more CO2 does not increase the capacity of air to absorb more IR at CO2 wavelengths, its just more molecules in the mass, same is true of NH4 & CFC's. Watervapor(latent heat), N₂ & O₂ kinetic energy are the dominant and overwhealming factors transporting heat from the surface to the statosphere where re-radiative loss becomes the dominant transport to space.

Shine a light an opaque sheet of paper, it is all absorbed. Add a second sheet behind it, no additional effect. the 1st hundered feet of atmosphere extinguishes IR absorbable by atmospheric CO2. There is nothing left to render an effect on global temperature by increasing the level of CO2 or other minority GHG gases.

[VOA]

Thin Polar Bears Called Sign of Global Warming

As for herds of Polar Bears that look like they just escaped a concentration camp...
I'd say what Enrico Fermi said in his skepticism about extra-terrestrials:
"So, why aren't they here?"

The only skinny polar bear I've seen on television has been the one on the Greenpeace fund-
raising infomercial.
All the ones I see (even in one major TV news story about skinny polar bears)
looked fairly beefy to me.
And all the others in "nature" documentaries are NOT malnourished.

If the polar bears are, in reality, going hungry, I more suspect that some fish that
the seals eat has probably been over-fished by the Japanese and/or to put
on the plate of yuppie seafood restaurants in San Francisco or Paris.

Or, global warming is such a hoax that the ice is too thick and the bears can't
get at their food...

[ancient_geezer]

Hansen thinks that absorption outweighs shading.

And therein lay the problem. Others of the same and even greater stature in the fields applicable to the study global climate and the impact of the "Greenhouse Theory" have a concern about "thinking" something as opposed to establishing it in a scientifically convincing manner.

Personally I am merely a retired programmer with computer sciences & physical chemistry background, long long ago and in a galaxy far far away, as some might put it.

For me the issue is not merely one of a proposed theory or a projection of possibilities for academic consideration. The issue has been made one having substantial political and global economic consequence out of political decisions based on belief in the validity of unproven models and the basis on which they are founded.

When world economies, national sovereignty and personal standard of living are at stake it behooves us to stand back and take a critical and closer look at concepts pushing for major political changes on the basis of the UN/IPCC global warming premises.

All sides of the issue need to presented and evaluated, there is scientific opinion other than that of the IPCC, their modelers and enviro-proponents in this. Thus far the counterpoint has been virtually drowned out by IPCC proponents. It is time for experimental verification and a full and open evaluation of the IPCC's GCMs which thus far has not be forth coming.

From a conservative view I see a strong and substantive dissent to the storyline projections and models from which they have been derived. Frankly, the dissent's objections are fully warranted as far as my abilities to determine such is concerned. I am all too familiar with physical modeling to be snookered in by the IPCC's variety upon which the global warming assessments rest. Such models may be wonderful tools for learning, but like an rms curve fit of a polynomial to a dataset. They cannot be relied upon the beyond the dataset they mimic, they make great interpolators and unreliable predictors.

The dissent's objections, at the least, deserve a full and open scientific hearing and debate, not the blowoff I have seen come from too many quarters with a finger in the political and money pots. It is that latter the concerns me deeply, and raises many red flags when I see the dissenting opinion virtually washed out in a deluge of media blather on global warming.

I'll continue to go along with these folks, until there is a clear and convincing demonstration of the validity the IPCC's Global Warming bandwagon. That clear and convincing demonstration answering the counterpoints has yet to surface, and mere academic creditials bolstering yet more words in not going to do it.

ANTI-GLOBAL WARMING PETITION PROJECT:

During the past 2 years, more than 17,100 basic and applied American scientists, two-thirds with advanced degrees, have signed the Global Warming Petition.

***

Nearly all of the initial 17,100 scientist signers have technical training suitable for the evaluation of the relevant research data, and many are trained in related fields. In addition to these 17,100, approximately 2,400 individuals have signed the petition who are trained in fields other than science or whose field of specialization was not specified on their returned petition.

Of the 19,700 signatures that the project has received in total so far, 17,800 have been independently verified and the other 1,900 have not yet been independently verified. Of those signers holding the degree of PhD, 95% have now been independently verified.

 

And what did they sign?

Global Warming Petition

We urge the United States government to reject the global warming agreement that was written in Kyoto, Japan in December, 1997, and any other similar proposals. The proposed limits on greenhouse gases would harm the environment, hinder the advance of science and technology, and damage the health and welfare of mankind.

There is no convincing scientific evidence that human release of carbon dioxide, methane, or other greenhouse gasses is causing or will, in the foreseeable future, cause catastrophic heating of the Earth's atmosphere and disruption of the Earth's climate. Moreover, there is substantial scientific evidence that increases in atmospheric carbon dioxide produce many beneficial effects upon the natural plant and animal environments of the Earth.

You have claimed I take a minority view:

"Again, you are taking a minority view."

I would submit there has been a majority view that has be silenced for all practical purposes by endangerment of funding and career when one is too vocal in their dissent touching environmental topics in academic circles today.

[Number_Cruncher]

From a website on boreholes:

"Whereas the depth of a temperature perturbation is related to the timing of surface changes, the shape of the perturbation reveals details of the surface temperature history. Positive temperature perturbations signify past warming; negative anomalies indicate cooling. The amount of surface warming or cooling can not be read directly from the temperature profile because of the attenuating and smearing features of heat conduction. Instead, the magnitude of surface temperature excursions that caused the subsurface anomaly are found by calculating perturbations for models with different surface temperature histories. A ground surface temperature history is selected that best explains the observed subsurface perturbation."

If the surface record is not properly calibrated, the borehole record will not be properly calibrated. The borehole records are not completely independent of the surface record, but Pielke's pressure measurements are independent and they show very little warming in the surface layer.

[Number_Cruncher]

More evidence of no global warming for 1980-1995 (from www.co2science.org):

Glacier Mass Balance Trends: Up or Down?

Reference

Braithwaite, R.J. 2002. Glacier mass balance: the first 50 years of international monitoring. Progress in Physical Geography 26: 76-95.

What was done

The author reviewed and analyzed mass balance measurements of 246 glaciers from around the world that were made between 1946 and 1995.

What was learned

Braithwaite's analysis reveals "there are several regions with highly negative mass balances in agreement with a public perception of 'the glaciers are melting,' but there are also regions with positive balances." Within Europe, for example, he notes that "Alpine glaciers are generally shrinking, Scandinavian glaciers are growing, and glaciers in the Caucasus are close to equilibrium for 1980-95." And when results for the whole world are combined for this most recent period of time, Braithwaite notes "there is no obvious common or global trend of increasing glacier melt in recent years."

What it means

"From the results of modeling," Braithwaite writes, "it seems almost certain that higher air temperatures, if they occur, will lead to increasingly negative mass balances." In terms of a global glacier mass balance trend over the period 1980-95, however, none is apparent. Hence, one is left to wonder whether (a) the modeling results are wrong, (b) there has been no global warming over the last two decades of the 20th century, or (c) a and b are both correct.

[cogitator]

Interesting in light of this:

DECLINE OF WORLD'S GLACIERS EXPECTED TO HAVE GLOBAL IMPACTS OVER THIS CENTURY

"The great majority of the world's glaciers appear to be declining at rates equal to or greater than long-established trends, according to early results from a joint NASA and United States Geological Survey (USGS) project designed to provide a global assessment of glaciers. At the same time, a small minority of glaciers are advancing."

and this:

GREENLAND ICE SHEET FLOWS FASTER DURING SUMMER MELTING

"New measurements show that the flow of ice in the Greenland ice sheet has been accelerating since 1996 during the summer melt season. The results suggest that the ice sheet may be responding more quickly to the warming climate than previously thought."

Note that the study cited in your post analyzed data through 1995.

Interesting world we live in, isn't it?

[cogitator]

First of all, I want to thank you and congratulate you for finding an explanation of how borehole temperature logs are used to generate a surface temperature record that is much easier to understand than anything I could find. With that in mind:

Instead, the magnitude of surface temperature excursions that caused the subsurface anomaly are found by calculating perturbations for models with different surface temperature histories. A ground surface temperature history is selected that best explains the observed subsurface perturbation."

Here's what I think this means, and I invite your comment: the way that a surface temperature history is generated using borehole temperatures is to create different theoretical surface temperature histories and then to use these histories to generate a borehole temperature (subsurface temperature) model. Then the model temperature curve is compared to the actual borehole temperature curve. The surface temperature history that generated the closest-fit of modeled borehole temperature to actual borehole temperature is chosen as the borehole "surface temperature" history.

Do you think that is accurate? If so, there is no calibrated surface temperature data that is being used as a reference for comparison. The only actual temperature data that is being examined are the borehole temperature logs.

Now, it makes some sense that as a starting point a surface temperature history similar to what has been observed at the surface would be one surface temperature history to use. But I would hope that the researchers would use alternative histories to verify the results and establish error bounds (the borehole temperature curves I have seen have shown upper and lower bounds).

[cogitator]

Ancient_Geezer:

I'm going to try and answer one of your three May 31st repoies to me a day, today, Thursday, and Friday. You write a lot and bring up a lot of issues. Therefore, it's difficult to concentrate on salient points or even to determine what points you consider most salient. So I may miss or delete something that you consider important. I will do my best.

Which majority? IPCC's? I wasn't aware that the experimental science was subject to democratic rule.

Hug and Barrett's results are either revolutionary or stunningly wrong. I already posted (in #138) the summarized reply from Houghton that points out an apparent basic understanding of atmospheric dynamics by Barrett. You did not comment on this.

The more I investigate, the more I find that there may be something significantly wrong with the theoretical basis of the "Greenhouse Effect", as it had been proposed first to argue for high surface temperatures of Venus, much higher than measurement has since show Venus to actually have, and now to argue a potential rise in earths global temperatures in much the same manner as the original greenhouse debate regarding the surface temperature of Venus.

Question 1: what would be the alternative source of heat for Venus?

Are Hansen's radiative forcings wrong for CO2?

Hansen is merely repeating IPCC on that forcing he hasn't justified it by an experimental showing and there is strong experimental evidence against it.

No one seems to know where or how IPCC came up with the 4w/m2 per 300ppm change in CO2 comes from. It appears to be one of those numbers everyone points to someone else as saying, but no one seems to nail down the source and experimental or theorectical verification of it.

One of the first papers is Manabe and Wetherald, in 1967. Best I could do on this was here:

6.3.1 Carbon Dioxide

"IPCC (1990) and the SAR used a radiative forcing of 4.37 Wm-2 for a doubling of CO2 calculated with a simplified expression. Since then several studies, including some using GCMs (Mitchell and Johns, 1997; Ramaswamy and Chen, 1997b; Hansen et al., 1998), have calculated a lower radiative forcing due to CO2 (Pinnock et al., 1995; Roehl et al., 1995; Myhre and Stordal, 1997; Myhre et al., 1998b; Jain et al., 2000). The newer estimates of radiative forcing due to a doubling of CO2 are between 3.5 and 4.1 Wm-2 with the relevant species and various overlaps between greenhouse gases included. The lower forcing in the cited newer studies is due to an accounting of the stratospheric temperature adjustment which was not properly taken into account in the simplified expression used in IPCC (1990) and the SAR (Myhre et al., 1998b). In Myhre et al. (1998b) and Jain et al. (2000), the short-wave forcing due to CO2 is also included, an effect not taken into account in the SAR. The short-wave effect results in a negative forcing contribution for the surface-troposphere system owing to the extra absorption due to CO2 in the stratosphere; however, this effect is relatively small compared to the total radiative forcing (< 5%)."

and here's the reference list: http://www.ipcc.ch/pub/tar/wg1/259.htm

(removed references/Venus material)

Until such time as Hug's experimental result is shown to be wrong by actual measurements in the atmosphere or that the experiment itself was unquestionably flawed by being unable to reproduce his results.

That's fine. As far as I can assess right now, Hug's experiment doesn't reproduce the dynamics of the atmospheric system. It's a closed-system experiment. That minimal assessment is based on the Houghton comment previously mentioned. This also applies to your comment below.

Seeing as the experiment was carried out with the same mixture of gases as that found in the atmosphere that should be the least that is necessary to controvert his findings.

Does Hug suggest that the radiation absorption characteristics of CO2 be ignored?

Because of the overlap of water vapor IR absorption spectum and heat transferred to N2 & O2 by kinetic collision, yes. Read the article.

Thanks for the clarification and I also got that from the article. That's the clear departure from orthodoxy on which your argument rests. Now, departures from orthodoxy are great and welcome in science, but if I may quote:

"Alas, to wear the mantle of Galileo it is not enough that you be persecuted by an unkind establishment. You must also be right."

I cannot tell if Hug and Barrett are right or not. And I'm not a scientist that could make the necessary analysis.

Here's what has to happen. Hug/Barrett et al. will have to convince a scientist or group of scientists "in the mainstream" that their argument has merit. Publication is the first step. If their argument is picked up, then it will be suitably debated and either supported or refuted. I again note that Houghton published a reply to Barrett in which he noted what appears to be a basic misunderstanding of atmospheric dynamics. If that is still a core misunderstanding, then Hug and Barrett's results are still very questionable.

If so, are CH4 and CFCs not significant either (they are described in the literature as much more potent GHGs, but their radiative forcing contribution is less than CO2 because their concentrations are so much lower.)

Their IR spectums are overlapped by water vapor as well, heat transport is still dominanted by kinetic collisions with N2 & O2 and water vapor, rather than IR re-radiation and re-absorption by those molecules. Same effect as was demonstrated by the Hug experiment, can apply to the CH4 & CFCs as well. Their admitted lower effects simply do not require us to carry out that experiment in order to establish a problem in the basic theory applied by the global warming theorists as represented by the IPCC and their apologists.

Thank you.

Does this consider longwave radiation? Doesn't seem to.

IR radiation is the longwave radiation on which all this debate is about, DUH!

That is clearer now.

The bottom line of Hug & Barrett, is that IR(i.e. longwave) absorption is saturated within the 1st hundred feet of the surface, the energy absorbed is passed on to N2 & O2 molecules in kinetic collisions and re-radation to the broader band absorption of water vapor, rather than the re-radiation of IR at re-absorbable (CO2, CH4, CFC) wavelengths envisioned in the IPCC models.

I agree with your assessment of the "bottom line" here. I will be very curious to see if (as I noted above) they can convince scientists in the climate science community that they are correct.

GHG contributions are minimal because there is very little energy transported by re-radiation of IR from the lower atmosphere to the upper atmosphere, the IR energy absorbed at the surface is predominately and in fact overwhealmingly transferred to N2 & O2 through kinetic collisions, and transported as latent heat and the broad IR absorption of watervapor.

(removed material)

The experiment to disprove Hug & Barret is very simple. Measure 15micron radiant flux (from CO2 absorption spectum) at the surface, then measure it 300 feet up in the atmosphere. If the flux is substantially the same, IPCC & the GCMs are vindicated as IR reradiation would be the dominant mode of heat transfer on which the GCMs stand.

That does seem pretty simple.

If the 15micron flux at 300ft above ground is substantially different, then Hug & Barret are vindicated.

This contention is disputed by the observed cooling of the stratosphere in satellite data, you know.

The statosphere loses heat to space, and it is to thin to absorb radiant energy released from blackbody radiation and from release of latent heat of water vapor transported to the upper atmosphere.

Really! Then why did the stratosphere get warmer after Mt. Pinatubo erupted in 1991?

You are basically saying that radiative transfer is negligible (as far as I can tell).

In the troposhere, like in transport from the surface.

But the transfer of heat into and out of the stratosphere is only radiative, there are no significant convective processes.

When I speak of the atmosphere in the context of heat transport from the surface, I am speaking of the troposphere.

The stratosphere is indeed radiative transfer, simply because it does not impede the transmission of IR by absorption, the mean free path of molecules is too high, not many molecules in the way to absorb the outgoing IR radiation. The is very little in the stratosphere to "transport" heat.

But the molecules in the stratosphere do absorb (and radiate) IR. That's why it's possible to measure the temperature of the stratosphere.

The heat in the troposphere is transported predominately by convection and transport of latent heat in water vapor carried by hot air to the upper troposphere.

Yes, that's entirely correct.

Please do not confuse the issues with symantics. My statements have been clear. The Stratosphere is not anywhere near the 1st hundred feet of the surface of the earth where IR from the surface is absorbed and dissapated into molecular motion rather than radiant energy.

I am clearer on your argument, which is based on the Hug and Barrett work. The problem is this: if there is no significant radiative transfer of heat from the lower troposphere to the stratosphere, then any changes in CO2 concentration in the lower troposphere would not affect the temperature of the stratosphere. The "standard" view is that increasing CO2 concentrations in the lower troposphere absorb increasing amounts of longwave (IR) radiation, preventing it from being radiated to the stratosphere. That process would result in stratospheric cooling. Stratospheric cooling is, in fact, observed. Thus, you have to account for the observed stratospheric cooling. Some of it, but not all, is attributable to ozone depletion. The remainder is currently attributed to GHG absorption of longwave radiation. For Hug and Barrett's work to be applicable, an alternative explanation for stratospheric cooling must also be provided.

[Scott from the Left Coast]

Find out their weight-loss secret and use it on American kids.

[RichInOC]

Ha! Actually, as anybody who's seen the commercials knows, polar bears prefer Coke.

[cogitator]

Find out their weight-loss secret and use it on American kids.

It's not a secret. They aren't eating as much as they need to.

[Rita289]

You're right! It's the Diet Coke! Polar bears are not part of the Pepsi Generation.

[ancient_geezer]

The problem is this: if there is no significant radiative transfer of heat from the lower troposphere to the stratosphere, then any changes in CO2 concentration in the lower troposphere would not affect the temperature of the stratosphere.

Precisely.

The "standard" view is that increasing CO2 concentrations in the lower troposphere absorb increasing amounts of longwave (IR) radiation, preventing it from being radiated to the stratosphere.

Which should give rise to Tropospheric warming according to the "standard" view, NO substantial warming in the Troposphere is occuring.

That process would result in stratospheric cooling. Stratospheric cooling is, in fact, observed. Thus, you have to account for the observed stratospheric cooling. Some of it, but not all, is attributable to ozone depletion.

Nothing to prevent additional water vapor from storing latent heat, it very efficiently picks up heat in evaporation as well as broadband IR absorption. Water Vapor is a couple of orders of magnitude better heat resevoir than CO2 is, as well as the fact that most of the heat held by water vapor is latent heat of vaporization & and fusion.

CO2 is a narrow band IR absorber and its latent heat characteristics are nul as far ast the atmosphere is concerned, which is why is fails do the job.

Stored as latent heat by water vapor, there is minimal temperature rise in the Troposphere,(could even fall under some conditions), allowing the Stratosphere to cool. Which is what we observe.

For Hug and Barrett's work to be applicable, an alternative explanation for stratospheric cooling must also be provided.

All that is needed is a mechanism for heat storage, water serves quite well and can explain why the Troposphere is not heating as expected in the "standard" view, and why the Stratosphere can cool, should ozone depletion not even required to explain cooling of the Stratosphere.

[ancient_geezer]

Question 1: what would be the alternative source of heat for Venus?

Remember it is not as hot as the greenhouse model ("standard" view) says it should be.

1) CO2 is not a "source" of heat in any case.

2) The only source of heat necessary is the sun, and being substantially closer provides considerable heat to assure Venus gets a sufficient supply of energy.

3) The atmosphere is 90 times as dense to act as thermal mass. That is all that is necessary, clouds are Sulfuric acid which provides an effective thermal mass as well.

[ancient_geezer]

Point is, all you have stated is predicated on a hypothetical role of anthropogenic CO2, with an apriori conclusion arising out of political agendas building on a manufactured crisis to legislate and garner political and economic power.

The sun and water vapor, cannot be made to fit that political role. CO2 being a byproduct of carbon burning, fits hat political "need" the environmental agenda provides. It isn't science that is driving the debate, it is pure and simple politics.

The Answer Lies Partly in a Better Understanding of Water's Role http://science.nasa.gov/newhome/headlines/essd06oct97_1.htm

A computer model is only as reliable as the physics that are built into the program. The physics that are currently in these computer programs are still insufficient to have much confidence in the predicted magnitude of global warming, because we currently don't understand the detailed physical processes of clouds that will determine the extent and nature of water vapor's feedback into the Earth's temperature. And the Intergovernmental Panel on Climate Change (IPCC) agrees: ``Feedback from the redistribution of water vapour remains a substantial uncertainty in climate models...Much of the current debate has been addressing feedback from the tropical upper troposphere, where the feedback appears likely to be positive. However, this is not yet convincingly established; much further evaluation of climate models with regard to observed processes is needed." - Climate Change 1995, IPCC Second Assessment

Images of the Earth, such as this one in the infrared, tell us much about the distribution of water vapor. Areas within the Earth's atmosphere that are extremely dry, especially in the tropics, can act as large "chimneys" that allow energy to freely radiate into space, enhancing the cooling of the Earth. The effects of the tropical dry troposphere are poorly understood, and currently are not well-incorporated into computer models of global warming.

[ancient_geezer]

The newer estimates of radiative forcing due to a doubling of CO2 are between 3.5 and 4.1 Wm-2 with the relevant species and various overlaps between greenhouse gases included.

As regards the forcing issue, again the number used it is merely to force inadequate models to approximate temperature of the troposphere by changing a coefficient, and is not based or derived from fundamental physics and science of CO2 thermal activity.

Adjusting a polynomial coeffecient to make its curve match a dataset range does not in any way imply a physical basis in interpolating a dataset's values. Likewise adjusting a coefficient to make a GCM fit a dataset does not imply the coefficient has a physical reality unless the entire model is truly an accurate representation of the real world. The GCMs "assessed" by IPCC do not have that fundamental characteristic. They have gross inadequecies, which is why the coefficient are changed. If IPCC GCM CO2 forcing coefficients were based in science & physics the coefficient would not be changing. There would be no "newer estimates".

The atmospheric CO2 concentration is known, the number applied for forcing should be a fixed value if it were derived from basic science, as opposed to making a model fit.

[ancient_geezer]

Then why did the stratosphere get warmer after Mt. Pinatubo erupted in 1991?

The effect of Volcanoes on the Stratosphere has nothing to do with hypothetical CO2 concentrations increasing forcing in the Troposphere. It has a great deal to do with the aerosols injected into the stratosphere which absorb radiant energy inducing higher molecular motion(i.e. raising temperature) of the stratosphere.

http://climate.envsci.rutgers.edu/robock/rogabs.html

"By scattering some solar radiation back to space, the aerosols cool the surface, but by absorbing both solar and terrestrial radiation, the aerosol layer heats the stratosphere."

As heat absorbing aerosols drop out of the statosphere or are otherwise removed through chemical interations with ozone and breakdown by ionizing radiation & UV, the stratosphere cools back down hence a dominant source of cooling of the statosphere becomes apparent. Hence the rise in statospheric temperature from El Chichon in '82 and cooldown of the troposphere from shading induced by stratospheric aerosols, and again, with an even greater impact, by Mt Pinatubo in '91.

[cogitator]

I'm combining a couple of your posts here.

The stratosphere loses heat to space, and it is to thin to absorb radiant energy released from blackbody radiation and from release of latent heat of water vapor transported to the upper atmosphere.

To which I replied via query about the observed warming of the stratosphere after the Mt. Pinatubo eruption.

Your reply: The effect of volcanoes on the stratosphere has nothing to do with hypothetical CO2 concentrations increasing forcing in the Troposphere. It has a great deal to do with the aerosols injected into the stratosphere which absorb radiant energy inducing higher molecular motion(i.e. raising temperature) of the stratosphere.

So first you've said that the stratosphere is too thin to absorb radiant energy, and then you note that it isn't, i.e., the injected aerosols impart a warming via greater molecular motion. I prefer the latter. The stratosphere warms and cools radiatively. You're a physical chemist, and while I couldn't pass the maths required for Berkeley graduate school P-chem, I know enough to say this: temperature is a measurement of the kinetic energy of the molecules in a gas, liquid, or solid. Right?

OK. Now you've proposed something quite interesting, which is that water vapor can explain a lot of what's not explained. That's quite consistent with the current state of knowledge regarding clouds and water vapor in the atmosphere.

All that is needed is a mechanism for heat storage, water serves quite well and can explain why the Troposphere is not heating as expected in the "standard" view, and why the Stratosphere can cool, should ozone depletion not even required to explain cooling of the Stratosphere.

The interesting thing about this to me is that the water vapor feedback is one of the primary positive feedbacks of GHG-induced warming. So, if you've got GHG-induced warming, and a water vapor feedback, then that's pretty much in-line with the mainstream view. Your major contention is still with the CO2 energy absorption.

[cogitator]

You might be interested in this, which apparently is a work-in-progress:

Arbiters of Energy