There has been a bit of a mystery over the Norwegian climate sensitivity study that found evidence of low climate sensitivity. In particular, a number of commentators have noted that there doesn't appear to be a peer reviewed paper as yet.
It appears from the Twittersphere that the press release was issued by the Norwegian Funding body, based on an internal report on the project from the scientists concerned, and without the approval of the scientists.
While we wait for a paper (and the data and code), there is this magazine article about the study (from page 8). The lead researcher appears to be Ragnhild Bieltvedt Skeie. Here are the key conclusions:
The RF time series...have been used in a Bayesian approach to constrain the climate sensitivity in a recent PhD thesis from the Institute of Geoscience, University of Oslo (Skeie, 2012) in collaboration with the Norwegian Computing Center. The probability density function for the climate sensitivity in this study is tighter and with a lower posterior mean value (1.9°C) compared to previous studies using the instrumental record to estimate the climate sensitivity (Hegerl et al., 2007). Also, values of the climate sensitivity larger than 4.5˚C are excluded. The observed ocean heat content over the recent decade is found to be important for the better constrained climate sensitivity in this study, however the historical ocean heat content data series have large uncertainties. In addition to improved data for the storage of heat in the ocean, improved knowledge of how aerosols affect the clouds and how this effect has altered the energy balance over the last century is crucial in future work for constraining the climate sensitivity.