The inclusion of the very warm 1998 El Nino year at the end (or start) of either of those two periods only has a significant
effect on the trend over the shorter period.
Global economic changes were also having
an effect on the trends.
Nothing to celebrate here... it simply underscores his ignorance of the field, as it has been known for years now that slicing and dicing the data many different ways, or using unadjusted vs. adjusted data (as he discusses), has virtually
no effect on the trend.
And
that effect on trend is stated as clear as day in the quote above from the ERSST.v4 paper.
Bias corrections which are stable over time will have a big effect on time averages, but
no effect on trends.
I have done a calculation here which I think shows
the effects on trend for both the SST and the land / sea averages.
So, for example, recent data will show smaller positive anomalies with respect to the 1981 — 2010 reference period than it will with respect to a (cooler) 1961 — 1990 reference period, but this has
no effect on trends (as illustrated in Figure 6).
The difference between the two creates
the effect on the trend.
Apple's abandonment of the headphone jack on the iPhone last year and the increasing adoption of jack-less designs from its Android rivals might also be starting to have
an effect on this trend.