Now we tackle, using newly available data, what may have caused the fictitious temperature trend in the latter decades of the 20th century. We first look at ocean data.  There was a great shift, after 1980, in the way Sea Surface Temperatures (SSTs) were measured (see Goretzki and Kennedy et al. JGR 2011, Fig. 2), "Sources of SST data."  Note the drastic changes between 1980 and 2000 as global floating drifter buoys geographic changes increasingly replaced opportunities for sampling SST with buckets. Data taken from floating drifter buoys increased from zero to 60% between 1980 and 2000.  But such buoys are heated directly by the sun, with the unheated engine inlet water in lower ocean layers.  This combination leads to a spurious rise in SST when the data are mixed together. In merging them, we must note that buoy data are global, while bucket and inlet temperatures are (perforce) confined to (mostly...(Read Full Post)