The green line shows the 25-year linear trend (0.19 ✬ per decade). The red line shows annual data, the larger red square a preliminary value for 2009, based on January-August. Global temperature according to NASA GISS data since 1980. 1990-1999, 1991-2000 and so on) have all been between 0.17 and 0.34 ✬ per decade, close to or above the expected anthropogenic trend, with the most recent one (1999-2008) equal to 0.19 ✬ per decade – just as predicted by IPCC as response to anthropogenic forcing.įigure 1. It does show up to some extent (no cooling, but reduced 10-year warming trend) in the Hadley Center data, but it does not show in the GISS data, see Figure 1. (2) It is highly questionable whether this “pause” is even real. Of course, the warming trend keeps going up whilst natural variability just oscillates irregularly up and down, so over longer periods the warming trend wins and natural variability cancels out. ~0.2 ✬) and can thus compensate for the anthropogenic effects. That simply is due to the fact that short-term natural variability has a similar magnitude (i.e. Even under conditions of anthropogenic global warming (which would contribute a temperature rise of about 0.2 ✬ over this period) a flat period or even cooling trend over such a short time span is nothing special and has happened repeatedly before (see 1987-1996). (1) This discussion focuses on just a short time period – starting 1998 or later – covering at most 11 years. Although we have discussed this topic repeatedly, it is perhaps worthwhile reiterating two key points about the alleged pause here.
#Pdo hockey full#
The blogosphere (and not only that) has been full of the “global warming is taking a break” meme lately.
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