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Pat Michaels: A Few Observations On The Latest BEST Kerfluffle And Recent Trends

The policy significance of BEST will be nil because the length of time it will take re-establish a warming trend since 1996 is too long to politically support any expensive intervention.

Observation #1: BEST, GISS, NOAA and CRU all use largely the same land data and, unless there’s some remarkable difference in analytical technique (BEST’s generation of trends after all discontinuities can’t make that much of a difference), they are pretty much going to show the same thing. BEST says the CRU data is the outlier in recent years.

Observation #2: A more independent adjudicator of recent times should not be a rehashing of tons of the same data. May I suggest the MSU and AMSU? In this case, the CRU data matches best (no double entendre’ intended).

Observation #3: The last ten years of the BEST data indeed show no statistically significant warming trend, no matter how you slice and dice them. The second-last data point is obviously wrong, but its removal still does not yield a statistically significant warming, in large part because the BEST data, being land data, are very noisy.

Observation #4: BEST is not about global temperature averages, and if we are interested in global temperature in recent years, let’s go back to global analyses, and use the MSU and the surface record it most corresponds to during the period in question, the CRU history.

Observation #5: Both records are in reasonable agreement about the length of time without a significant warming trend. In the CRU record it is 15.0 years. In the University of Alabama MSU it is 13.9, and in the Remote Sensing Systems version of the MSU it is 15.6 years.

Observation #6: A significant trend since these periods began is not going to emerge anytime soon. MSU temperatures are plummeting and are now below where they were at this time of the year in the 2008 La Nina. NOAA is predicting an extreme La Nina low in 2012. If the 1976-98 warming trend is re-established in 2013, post-1996 warming would not become significant until 2021.

Observation #7: While is not scientifically appropriate to start a trend analysis at one selected point, that is precisely what the political process will do. I do not see how any expensive policy is going to hold up against 24 years without a trend in the face of rapidly increasing atmospheric carbon dioxide concentrations.

In summary, while BEST finds the CRU data to be an outlier with regard to recent trends, the more independent satellite agrees more with the CRU data than NASA, NOAA, or BEST. The policy significance of BEST will be nil because the length of time it will take re-establish a warming trend since 1996 is too long to politically support any expensive intervention.