Next topic:
Stefan-Boltzmann is first principles. It doesn't take into account positive feedback cycles, the most important of which is the increase in atmospheric water vapor that accompanies warming. I was so bothered by this the last time it came up on FR that I emailed Hansen and got an explanatory reply about it. That's why the increase due to CO2 (direct forcing) is less than the estimated total climate forcing.
If so, do you agree that the apparent range of estimated forcing for the increase in atmospheric CO2 from 1850 to present is 0.30 - 1.30 W m-2?
I will agree that global tropospheric temperature has increased less than 0.5 C since 1850 for numerous causes including changes in solar irradiation, albedo, & GHG's.
That's not what I asked. First you estimate forcing, then you try to assess the temperature change. As we both know, that's fraught with difficulty.
Hug's work is controversial and has yet to be assessed by the climate community. It essentially constitutes a lower-bound if it's correct. Reliance on lower- bound estimates is just as dangerous as reliance on upper-bound estimates. It's clear that the oft-quoted, very-stupid IPCC upper bounds are just as unlikely to be correct as the never-quoted, just-as-stupid lower bounds. Any legitimacy in prediction (which is questionable anyway) is going to be found where there is something of a convergence in independent model output.
So now I would refer back to post 100 in this thread, with the IPCC output projections. And this figure:
Global Warming: 4-7 Degree [F] Temperature Rise Likely by 2100
"An estimated global warming range of 2.5–10.4°F was announced earlier this year by the Intergovernmental Panel on Climate Change (IPCC), composed of hundreds of scientists around the world. But the likelihood that the earth's temperature would warm only 2.5° or as much as 10.4° is very low, say NCAR's Wigley and coauthor Sarah Raper of the University of East Anglia in England and the Alfred Wegener Institut for Polar and Marine Research in Germany."
Since it gets confusing to mix Fahrenheit and Celsius, the equivalent Celsius range for the IPCC ranges is 1.5 - 6.2 deg. C. So I'm comfortable, and I'm probably "riding with" Hansen, to think that the most likely warming in the next century will be on the order of 1.8 deg C.
Does that make me an alarmist? I don't think so. It's about 3x as much as happened this century. And according to ecological studies, it's just under the amount of change ecosystems can tolerate and adapt to before exhibiting significant detrimental effects.
That's all I have time for now. I may have one more shot at it Friday before a break until around June 12.
C:If so, do you agree that the apparent range of estimated forcing for the increase in atmospheric CO2 from 1850 to present is 0.30 - 1.30 W m-2?
AG: I will agree that global tropospheric temperature has increased less than 0.5 C since 1850 for numerous causes including changes in solar irradiation, albedo, & GHG's.
C: That's not what I asked. First you estimate forcing, then you try to assess the temperature change. As we both know, that's fraught with difficulty.
Since water vapor concentration and its effects on aldebo so tremendously outweigh all other considerations in atmospheric heat transport, the presumption of CO2 being a significant factor is tenuous at best.
As I have previously stated, CO2 concentration is predominately an effect of change in temperature and other causes, and not a substantive cause of temperature change.
The problem lay in the apriori attribution by some of CO2 as being a significant factor in the heat budget, and underplaying the role of H2O as a greenhouse gas and solar irradiation as the prime mover in the whole machine.
Hug's work is controversial and has yet to be assessed by the climate community. It essentially constitutes a lower-bound if it's correct.
So was Galileo's work.
Hug's work is a direct assessment of the actual IR absorption on which the CO2 greenhouse sensitivity depends. One experiment is worth a million words of controversy. Hug did the experiment, the CGM modelers and IPCC have offered only theoretical speculation as to what CO2 IR absorption ought to be under ideal (i.e. H2O free) conditions. Hug's result in the presense of H20 has established reality can be substantially different from the ideal speculations by up to 2 orders of magnitude. The global warming(i.e. IPCC etc.) folks have yet to provide any experimental evidence they are correct in their speculative assumptions nor do they in anyway controvert Hug's results.
Here is a summary Hug's response to the GW community's, 100's of "scientists" in regards IR absorption and other objections.
Hug & Barret,
DECHEMA colloquium, Frankfurt on 11th Oct, 2001
"An estimated global warming range of 2.5–10.4°F was announced earlier this year by the Intergovernmental Panel on Climate Change (IPCC)"
Problem is IPCC depends on the CGMs and the assumptions inherent in them, which are very clearly flawed and incomplete. Other estimates based in emperical and theretical concerns, not just IPCC's CGMs, range from 1.4oC(2.5oF) downward. With historical 100yr variability studies indicating a range of +1.4oC(2.5oF) upper probability(1s) boundry and -1.0oC(1s) lower boundry.
Frankly, as I have said, there very well be be a degree of warming going on. But the state of knowledge in atmospheric science, especially as regards the full roles of water vapor in the atmosphere, does not allow anyone to make predictions for the next 30days much less 100 yrs.
The UCAR pictorial of probability, is nothing more than a reflection of IPCC model variablility and does not reflect the natural variability of the real world, only the GW apriori assumptions that anthropogenic changes in GHG concentrations must cause substantive upward temperature change.
"New estimates of sulfur dioxide and other emissions, along with updated information on carbon storage, ocean circulation, radiation, and other components of the earth system have improved computer models of the earth's climate and led the IPCC to both raise and widen its estimated range of global temperature increase. The latest range of 2.5-10.4°F is up significantly from the panel's 1995 estimates of 1.4–6.3°."
This just a repeat of the same model outputs over again in another form, no indication they have impoved there water vapor models, which they have not done.
I repeat, others using both theoretical and empirical studies come up with an entirely different set of projections ranging downward from the IPCC low.
I find it interesting that out of all the range provided, the GW folks never present or even apparently consider the possibility that global climate temperatures can fall as well as rise. This is a telling note. They appear to be totally dedicated to demonstrating rising global temperture inspite of historical evidence that climates tempertures make excursions downward even with atmospheric CO2 concentrations much higher than even those assumed doublings of IPCCs GCM story lines.