One of the most annoying climate-denial memes has been the supposed “global warming hiatus.” It goes something like this: 1998 was a spectacularly hot year. It has not been as hot since then, thus global warming has stopped. Anyone with a passing familiarity with variance should see right through that one, but now we have a study in Science that pretty much nails it dead to rights:
Much study has been devoted to the possible causes of an apparent decrease in the upward trend of global surface temperatures since 1998, a phenomenon that has been dubbed the global warming “hiatus.” Here we present an updated global surface temperature analysis that reveals that global trends are higher than reported by the IPCC, especially in recent decades, and that the central estimate for the rate of warming during the first 15 years of the 21st century is at least as great as the last half of the 20th century. These results do not support the notion of a “slowdown” in the increase of global surface temperature.
And thus, in sum:
newly corrected and updated global surface temperature data from NOAA’s [National Centers for Environmental Information] do not support the notion of a global warming “hiatus.” As shown in Fig. 1, there is no discernable (statistical or otherwise) decrease in the rate of warming between the second half of the 20th century and the first 15 years of the 21st century. Our new analysis now shows the trend over the period 1950-1999, a time widely agreed as having significant anthropogenic global warming (1), is 0.113°C dec−1, which is virtually indistinguishable with the trend over the period 2000-2014 (0.116°C dec−1). Even starting a trend calculation with 1998, the extremely warm El Niño year that is often used as the beginning of the “hiatus”, our global temperature trend (1998-2014) is 0.106°C dec−1 – and we know that is an underestimate due to incomplete coverage over the Arctic. Indeed, based on our new analysis, the IPCC’s (1) statement of two years ago – that the global surface temperature “has shown a much smaller increasing linear trend over the past 15 years than over the past 30 to 60 years” – is no longer valid.
Note well: there is a problem with IPCC estimates: they underestimate the degree of warming. The game of climate denial whack-a-mole will continue, but in the meantime, cue Freddie Mercury: