A new paper in Nature: Scientific Reports by Santer et al entitled Tropospheric Warming Over the Past Two Decades begins with this:
After a recent Senate confirmation hearing, Scott Pruitt the new Administrator of the U.S. Environmental Protection Agency received a written question regarding observed warming estimates. In response, Mr. Pruitt claimed that over the past two decades satellite data indicates there has been a leveling off of warming. We test this claim here.
Now, exactly how does one scientifically test a claim of “leveling off of warming”?
First, the claim would have to have some unambiguous meaning which can be evaluated quantitatively. Does it mean that warming has decelerated in the last two decades, and is approaching zero? That would be my first interpretation of “leveling off”.
And by “two decades” did Pruitt mean exactly 20 years?
The wording is ambiguous. But the authors decided Pruitt meant “there has been zero warming” for exactly 20 years. They proceeded to evaluate this interpretation with a statistical analysis of the various satellite temperature datasets, as well as with climate models.
The result is a peer-reviewed study which took less than one month to sail through peer review.
Wow. If I only knew earlier that I could get peer-reviewed scientific papers by evaluating the silly climate claims made by politicians (Al Gore, Barack Obama, et al.) over the years.
Oh, that’s right. I’m on the wrong side of the issue. The reviewers would have said, “C’mon, that’s a politician generalizing. You can’t get a peer-reviewed scientific paper out of that!”
Why the Global Warming Pause (Hiatus, Leveling Off) is a Poor Metric
I’ve warned people not to place too much emphasis on the claim that there has been zero warming for the last x number of years.
First of all, when the next big warm El Nino occurs, the zero trend will end. And that’s exactly what happened, with the 2015-16 El Nino. A trend is very sensitive to what happens at the end of a time series, and a big (natural) warm blip from El Nino is just what the doctor ordered. No more zero trends.
Now Santer et al. can get the press saying, in effect, “See? Those silly global warming skeptics are wrong.” Of course, the authors know full well that the reason the pause/hiatus/leveling-off ended was due to a NATURAL event (El Nino). So, they fault Pruitt on a technicality, straining a gnat while swallowing a camel.
This then distracts attention from the real issue: that the climate models on average produce about twice as much warming as has been observed over the last few decades.