Since 2000, there have been a number of very important new studies, increasing the estimated NIR absorption parameters of water vapor, stimulated by the discovery of the HITRAN-96 clerical errors, but amounting to significant increases over and above those errors. The increases seem to account for much missing atmospheric absorption. Again, the issue here is not the "greenhouse" effect of water vapor, but a type of anti-greenhouse effect of water vapor, whereby water vapor absorbs incoming solar radiation in near infra-red (NIR) and visible wavelengths, rather than absorbing outgoing IR wavelengths. This directly cuts into hypothesized positive feedback effects of increased IR absorption of water vapor by creating a negative feedback. Belmiloud et al  with a variety of blue-chip authors have a compelling cut-phrase:
There is another lesson to be learned. Making sure the database is valid is necessary foundation for all modelling of atmospheric radiation transfer, especially so when theory and observation fail to agree.
Here are some references: Djedjiga Belmiloud, Roland Schermaul, Kevin M. Smith, Nikolai F.Zobov, James W. Brault, Richard C. M. Learner, David A. Newnham, and Jonathan Tennyson , New Studies of the Visible and Near-Infrared Absorption by Water Vapour and Some Problems with the HITRAN Database, GEOPHYSICAL RESEARCH LETTERS, VOL. 27, NO. 22, PAGES 3703-3706, NOVEMBER 15, 2000 http://www.tampa.phys.ucl.ac.uk/jonny/papers/262.pdf
Abstract. New laboratory measurements and theoretical calculations of integrated line intensities for water vapour bands in the near-infrared and visible (8500-15800 cmà⣃ ’ ”¬’¢1) are summarised. Band intensities derived from the new measured data show a systematic 6 to 26% increase compared to calculations using the HITRAN-96 database. The recent corrections to the HITRAN database [Giver et al., J. Quant. Spectrosc. Radiat. Transfer, 66, 101-105, 2000] do not remove these discrepancies and the differences change to 6 to 38 %. The new data is expected to substantially increase the calculated absorption of solar energy due to water vapour
Roland Schermaul, Richard C. M. Learner, David A. Newnham, John Ballard, Nikolai F. Zobov, Djedjiga Belmiloud and Jonathan Tennysonz, The Water Vapor Spectrum in the Region 8600–15 000 cm-1: Experimental and Theoretical Studies for a New Spectral Line Database II. Linelist Construction, Journal of Molecular Spectroscopy 208, 43–50 (2001) http://www.tampa.phys.ucl.ac.uk/jonny/papers/270.pdf
The new laboratory measurements of R. Schermaul et al. (J. Mol. Spectrosc. 208), for the near-infrared and visible spectrum of water vapor, covering the 2º C ±, 3º, 3º C±, and 4º polyads, are combined with accurate calculations of weaker lines to provide a new, comprehensive linelist of water transitions for the spectral region 8600–15 000 cm¡1. The resulting ESA–WVR linelist reproduces the raw laboratory observations to a high level of agreement at all but the longest wavelengths. This linelist has been made available in a standard format for general use.
L. S. Rothman and J. Schroeder, Millennium HITRAN Compilation, Twelfth ARM Science Team Meeting Proceedings, St. Petersburg, Florida, April 8-12, 2002 http://www.arm.gov/publications/proceedings/conf12/extended_abs/rothman-ls.pdf Roman N. Tolchenova, Mizuho Tanaka, Jonathan Tennyson; Nikolai F. Zobova, Sergei V. Shirina, Oleg L. Polyansky, Ahilleas N. Maurellis, Water line intensities in the near-infrared and visible, Journal of Quantitative Spectroscopy & Radiative Transfer 82 (2003) 151–163 http://www.tampa.phys.ucl.ac.uk/jonny/papers/317.pdf
Water is the single most important molecule for models of the earth’s atmosphere but line parameters for water, particularly at shorter wavelengths, are dierent results. The experimental data used to construct the ESA-WVR linelist (J. Mol. Spectrosc. 208 (2001) 32) is re-analyzed with a focus on e>ects due to pressure determination in the cell, subtraction of the baseline and parameterization of the line pro=les. A preliminary re-analysis suggests that the line intensities given by the ESA-WVR study should be closer to those of Brown et al. (J. Mol. Spectrosc. 212 (2002) 57) used in the HITRAN. This shows the vital importance of validating the data for water by independent means.
P. Albert, K.M. Smith, R. Bennartz, D.A. Newnham, J. Fischer, Satellite- and ground-based observations of atmospheric water vapor absorption in the 940 nm region, Journal of Quantitative Spectroscopy & Radiative Transfer 84 (2004) 181–193 http://naftali.meteor.wisc.edu/~ralf/jqsrt_albert_line_absorption_2003.pdf
ments of direct absorption of solar radiation between 9000 and 13; 000 cmà⣃ ’ ”¬’¢1 (770–1100 nm) with a spectral resolution of 0:05 cmà⣃ ’ ”¬’¢1 are compared with line-by-line simulations of atmospheric absorption based on di:erent molecular databases (HITRAN 2000, HITRAN 99, HITRAN 96 and ESA-WVR). Di:erences between measurements and simulations can be reduced to a great amount by scaling the individual line intensities with spectral and database dependent scaling factors. Scaling factors are calculated for the selected databases using a Marquardt non-linear least-squares @t together with a forward model for 100 cmà⣃ ’ ”¬’¢1 wide intervals between 10,150 and 11; 250 cmà⣃ ’ ”¬’¢1 as well as for the water vapor absorption channels of the Medium Resolution Imaging Spectrometer (MERIS) onboard the European Space Agency’s (ESA) ENVISAT platform and the Modular Optoelectronic Scanner (MOS) on the Indian IRSP-3platform, developed by the German Aerospace Centre (DLR). For the latter, the scaling coeEcients are converted into correction factors for retrieved total columnar water vapor content and used for a comparison of MOS-based retrievals of total columnar atmospheric water vapor above cloud-free land surfaces with radio soundings. The scaling factors determined for 100 cmà⣃ ’ ”¬’¢1 wide intervals range from 0.85 for the ESA-WVR molecular database to 1.15 for HITRAN 96. The best agreement between measurements and simulations is achieved with HITRAN 99 and HITRAN 2000, respectively, using scaling factors between 0.9 and 1. The e:ects on the satellite-based retrievals of columnar atmospheric water vapor range from 2% (HITRAN 2000) to 12% (ESA-WVR).
Maurellis, A. N., Lang, R., Williams, J. E., van der Zande, W. J. Smith, K. Newnham, D. A.,Tennyson, J., Tolchenov, R. N., Weakly Interacting Molecular Pairs: Unconventional Absorbers of Radiation in the Atmosphere, Proceedings of the NATO Advanced Research Workshop, p. 259-272, 2003