In Eli's continuing series from the replies to the EPA endangerment finding for CO2 pollution, we get the final work on Miskolczi and the majic humidifier. As Nick Stokes said, you can sum up Miskolczi as "the greenhouse effect doesn't exist, the proof is left as an exercise for the reader.
Commenter (3701.1) requests that EPA analyze Miskolczi's theory (Miskolczi 2007) that water vapor balances out CO2 forcing. Commenter 3535 submits a statement by Miskolczi that claims that the National Oceanic and Atmospheric Administration (NOAA) National Centers for Environmental Protection (NCEP)/National Center for Atmospheric Research (NCAR) reanalysis data show a slight decrease in global average absolute humidity in the past 61 years, which compensates for increases in GHGs.
Another commenter submits Paltridge et al. (2009), which also found decreasing absolute humidity at high altitudes from the NCEP data. Some (0798, 2982) cite Miskolczi (2007), which theorizes that water vapor will condense or evaporate as needed to maintain a constant greenhouse effect, citing a finite atmosphere used in calculations and observed decline in upper atmosphere humidity as validating factors. A number of other commenters (3323.1, 4003, 4041.1, 4932.1, and 5158) state that the lack of observed constant humidity levels are contrary to anthropogenic global warming theory and the IPCC
The hypothesis that increased CO2 forcing will lead to a counterbalancing decrease in water vapor is highly speculative, and is not supported by the vast body of scientific literature. Miskolczi claims that the greenhouse effect should maintain a balance, so that every increase in a GHG should lead to a corresponding decrease in water vapor (and vice versa), effectively implying a climate sensitivity of zero.
A climate sensitivity of zero is completely incompatible with historical temperature variations, as it would imply an unchanging climate in direct contrast to historically recorded temperatures changes on all timescales. Miskolczi also claims that “On global scale, however, there can not be any direct water vapor feedback mechanism, working against the total energy balance requirement of the system. Runaway greenhouse theories contradict to the energy balance equations and therefore, can not work.” This demonstrates a lack of understanding of feedback mechanisms in the climate (see response in Volume 4 for a discussion of runaway climate).
Several commenters also cite evidence for decreasing absolute humidity, in contrast to the IPCC conclusions (cited in the TSD) that “[a]lthough surface specific humidity globally has generally increased after 1976 in close association with higher temperatures over both land and ocean, observations suggest that relative humidity has remained about the same overall, from the surface throughout the troposphere (Trenberth et al., 2007).” The data from the NOAA NCEP/NCAR reanalysis for humidity has been questioned in other papers (Soden et al., 2005) (especially for the pre-satellite period), and a Dessler et al. (2009) review also contradicts this data. Even Paltridge et al. (2009), which relied on the NCEP reanalysis data, recognized that “[i]t is accepted that radiosonde-derived humidity data must be treated with great caution, particularly at altitudes above the 500 hPa [hectopascal] pressure level.”
Falling absolute humidity during a period of warming is also difficult to reconcile with theoretical understanding, model results, and historical temperature trends. The analysis in the IPCC (Trenberth et al., 2007) stated: “Due to instrumental limitations, long-term changes in water vapour in the upper troposphere are difficult to assess,” but nonetheless concluded: “To summarise, the available data do not indicate a detectable trend in upper-tropospheric relative humidity. However, there is now evidence for global increases in upper-tropospheric specific humidity over the past two decades, which is consistent with the observed increases in tropospheric temperatures and the absence of any change in relative humidity.”
No trend in upper- tropospheric relative humidity, and evidence for increases in specific humidity, are consistent with model predictions that relative humidity should stay fairly constant, implying increasing absolute humidity with increasing temperature, and therefore a positive feedback (see response on Volume 4 for more responses on relative humidity predictions in models).