Ross McKitrick

CORRECTION to MMH10: In 2010 Steve, Chad and I published a paper that applied panel and multivariate (VF) methods to test the significance of trends and of model-obs differences in the tropical troposphere. There were a couple of typos, and also Chad discovered an error in the GISS data as archived at the PCMDI (not a huge one, just an error splicing pre- and post-2000 runs together). We re-did our analyses and used the updated versions of the observational data for the purpose. The correction has been published:

• McKitrick, Ross, Stephen McIntyre and Chad Herman (2011) Correction to "Panel and Multivariate Methods for Tests of Trend Equivalence in Climate Data Series" Atmospheric Science Letters October 7 2011, DOI: 10.1002/asl.360. 

The GISS correction and data revisions strengthen all our original findings, reducing the observational trends and raising (slightly) the model trends. (a) The combined MSU trends have a p-value just over 0.05; still significant but "marginal". (b) The HadAT 1979-2009 trend in the LT drops from significance to marginal. (c) The average 1979-2009 MT trend across all observational series drops to insignificance. (d) The RICH 1979-2009 MT trend drops to insignificance. (e) The RSS 1979-2009 MT series is now significantly different from models in the panel regression test. For the 1979-2009 interval, all observational series individually and jointly are significantly below models at both the LT and MT layers. (f) Over the 1979-1999 interval the model-obs differences are still marginally significant but in the MT layer it is now at about the 6% level, so it is nearly significant. 


SENATE TESTIMONY: December 15 2011 I testified before the Senate Standing Committee on Energy, Environment and Natural Resources in Ottawa. Unlike in the US, our Senate has little formal power, but does play an advisory role to the House of Commons in the formation and passage of legislation ("sober second thought" as the tradition goes). 


REPORT ON THE IPCC: FIX IT OR NIX IT, so to speak. I have published a report through the UK Global Warming Policy Foundation that reviews the assessment procedures of the IPCC and makes a series of recommendations for reform. The report is available here. I have also published an op-ed in the Financial Post describing the report. The report would have been an important point of discussion in any case, but in light of the release today of the  Climategate II emails, it is even more timely. 



SIMPLIFIED WEB ADDRESS: I finally got around to upgrading my weebly account so that the domain for this site is now simply rossmckitrick.com, without the 'weebly' in the middle.


BEIJING FORUM: I was invited to speak to the 2011 BeiJing Forum being held at Peking University, November 4-6. My presentation is here. I also presented on State-Contingent Emission Fees at the Peking University School of Engineering and Environmental Science and the Central University of Finance and Economics. 


THIRD AGE LEARNING SOCIETY: I made a presentation to a large group of retirees on campus (Sept 28 2011) at the Arboretum, entitled "Global Warming: Who's Disagreeing with What?" My slides are here in PDF format. 

TROPOSPHERIC TRENDS: MODELS vs OBSERVATIONS ROUND II: In fall 2010 I published a paper with Steve McIntyre and Chad Herman comparing climate model-generated predictions to observations from satellites and weather balloons in the lower- and mid-troposphere over the tropics, a key region for assessing climate model validity. That paper applied two methods, the panel model, which is a fairly well-known econometric method, as well as the Vogelsang-Franses multivariate trend estimation method, a less-well known but superior alternative which adapts the general HAC method to the estimation of robust confidence intervals for linear trends. The data set used in MMH spanned 1979 to 2009. I extended the data set to include weather balloon data back to 1958 for the purpose of comparing observed lower- and mid-troposphere trends in the tropics to climate model predictions. A challenge in this case is that the 1977-78 Pacific Climate Shift introduces a step-like change in the mean of the data which causes a spurious increase in the estimated trend. But controlling for the step-change affects the VF critical values. Tim Vogelsang has extended the theory behind the VF method to yield robust trend variances in the presence of autocorrelation of unknown form when a step-change occurs at a known point in the sample. In our new paper, just released as a Discussion Paper and en route to a journal, Tim and I present a detailed explanation of the HAC approach to trend comparisons, including the relevant asymptotics and a bootstrap method for generating empirical critical values, then we apply the method to the Hadley and RICH balloon data for the tropical troposphere. 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.