The United Nations panel of climate science experts mentioned it in a 2013 report, scientists have published more than 200 papers analyzing it, and climate deniers said it was proof that climate change didn’t exist, but in reality the global warming “pause” or “hiatus” never occurred.
That is the conclusion of a pair of studies, published Tuesday in the scientific journal Environmental Research Letters, based on statistical reassessments of a recent 10-year period that appeared at the time to evince a flattened warming curve.
These are the latest of several assessments to caution that the hiatus theory has no real significance either for climate science or for science-based policy. Even so, they seem unlikely to stamp out the discussion, which has become a deeply embedded meme in some circles.
“In hindsight, with current GMST [Global Mean Surface Temperature] datasets, there is no statistical evidence for a ‘pause,'” concluded one of the two studies, which reassessed temperature monitoring from the late 1990s and early 2000s.
The second study, which focused on what appeared to be a difference in observed temperatures and earlier projections from climate models, reached a similar conclusion.
“There was a natural slowdown in the rate of warming during roughly the decade of the 2000s due to a combination of volcanic influences and internal climate variability, but there was no actual ‘hiatus’ or ‘pause’ in warming,” Michael Mann, director of the Earth System Science Center at Pennsylvania State University and an author of the climate modeling study, said.
I clobbered Senator Ted Cruz for his parroting of the “pause” talking point.
A Lack of Arctic Data
The notion of a pause in warming from approximately 1998 to 2012, was fueled in part by incomplete data and erroneous projections that have since been corrected, the studies conclude.
It’s long been obvious that if there had been any blip in the trends it was temporary. The years that followed have hit new temperature records.
And new evidence has made clear why some were fooled.
Scientists know, for example, that the Arctic is warming at a faster rate than the planet as a whole, but there weren’t enough temperature observations from the Arctic in the early 2000s to accurately measure the changes that were occurring there. As a result, data sets on global temperature tended to omit the Arctic until recently, when researchers came up with a better way to extrapolate data from the region.
“We simply didn’t have all the information available at the time,” Stephan Lewandowsky, a researcher at the University of Bristol and lead author of the climate modeling report said.
Natural phenomena, including increased volcanic activity and decreased solar activity, also masked human-caused warming during the late ’90s and early 2000s, seemingly deviating from what climate models had projected, Lewandowsky said.
When scientists noticed a difference between observed temperatures and temperatures projected in climate models, they dug deeper into the science.
“When things don’t look quite how you expect, you dive into it,” said Gavin Schmidt, a climate scientist and director of the NASA Goddard Institute for Space Studies. “People looked into it, and it turned out to be nothing.”
I interviewed an all star panel on this in 2013.
There are tons of studies arguing that the 1998-2012 “hiatus” was a result of fluctuation. But the amplitudes of fluctuation are also getting larger with the rising amout of energy in the climate system.
Two articles, two different approaches coming to a similar result:
https://www.nature.com/articles/s41598-017-00319-0
https://www.theguardian.com/environment/climate-consensus-97-per-cent/2018/aug/29/global-warming-is-intensifying-el-nino-weather
More energy pulling on mother nature’s forces makes the oscillation larger. My 50 cents.
You might be right about the oscillation increasing. Tamino was pointing out the same thing, regarding Arctic sea ice, at his Open Mind blog.
https://tamino.files.wordpress.com/2017/11/anomaly.jpg
I saw a general talk on this topic a few years ago. I don’t recall whether any reason was hypothesized but it was noted that systems in general that are moving from one steady state to another tend to have increasingly large fluctuations until they switch.
Sort of like a giant “hit and miss” engine—-gets “goofy” just before it stops and then the various governors/feedbacks get it going again.
https://youtu.be/0w5OII6h504
Anyway, the “hiatus” is history and we’ve seen temperatures rising in giant steps.
We won’t hear the end of it. The 2016 +1.55C will be the new start point for climate denialists….
“Look! Global Warming ended 2 years ago! We’re cooling!! Look out for the Ice Age! We NEED MORE CO2 to save us!”
This one is playing with the semantics because Wally Broecker’s global warming with its diverse collection of amateurish definitions doesn’t ever include OHC anomaly. Still the coal/oil shills likely haven’t obtained an enforceable copyright on playing with words for the best for their team so it’s all fair game if that’s what interests you. If you’re interested in actual physical science I’ve already pointed you to what happened and it started 1990 AD (I think that might even be on Cheng’s OHC plot).