The title is blatantly stolen from the Climate Etc. Blog. There is uncertainty and there is uncertainty or ignorance. The "Pause", is the climate shift that started in 1995 though it probably started in 1990 and was interrupted by Pinatubo. So the "significance" of the "pause" is now the new rehash on Climate Etc.
Sequential Linear Regressions (SLR) is a way to "Gut Check" a trend significance. Scientist don't like that kinda talk, they want peer reviewed proof, but once again into the lack of peer reviewed breach.
The difference between 0.12 and 0.013 is small, indicating that there is not enough statistical difference between 15 year trends and 20 year trends for this portion of the "average" of this time series, to worry about.
There are plenty of other "peer reviewed" methods that can be used, but this is a very simple, "gut check" method that is in keeping with, Exploratory Data Analysis (EDA), which is basically, LOOKING at the data.