Ross McKitrick has a new discussion paper out. This is an extension to the McKitrick, McIntyre and Herman paper that came out last year. In the earlier paper, MMH found evidence that climate models were overstating warming, particularly for observations that were right up to date. The new paper looks at the so-called "Pacific Climate Shift" of 1977-8 and develops a new method to determine confidence intervals when this shift is taken into account in the statistical model.
As our empirical findings show, the detection of a trend in the tropical lower- and midtroposphere data over the 1958-2010 interval is contingent on the decision of whether or not to include a mean-shift term at January 1978. If the term is included, a time trend regression with error terms robust to autocorrelation of unknown form indicates that the trend observed over the 1958-2010 interval is not statistically significant in either the LT or MT layers. Most climate models predict a larger trend over this interval than is observed in the data. We find a statistically significant mismatch between climate model trends and observational trends whether the meanshift term is included or not. However, with the shift term included the null hypothesis of equal trend is rejected at much smaller significance levels (much more significant).
Or in Ross's layman's terms summary:
Controlling for the 1977 Pacific Climate Shift we find the trends are insignificant from 1958-2010 and the discrepancy with climate models is highly significant.