Bob Tisdale has already effectively dealt a death-blow to Michael Mann’s claims, here: On Steinman et al. (2015) – Michael Mann and Company Redefine Multidecadal Variability And Wind Up Illustrating Climate Model Failings
But, this recent press release deserves some exposure for the sheer audacity of the claims made by Mann in it. I wonder if Mann is even cognizant of just how AWOL the climate models were at predicting what he claims?
From Penn State:
Interaction of Atlantic and Pacific oscillations caused ‘false pause’ in warming
The recent slowdown in climate warming is due, at least in part, to natural oscillations in the climate, according to a team of climate scientists, who add that these oscillations represent variability internal to the climate system. They do not signal any slowdown in human-caused global warming.
“We know that it is important to distinguish between human-caused and natural climate variability so we can assess the impact of human-caused climate change on a variety of phenomena including drought and weather extremes,” said Michael Mann, Distinguished Professor of Meteorology, Penn State. “The North Atlantic and North Pacific oceans appear to be drivers of substantial natural, internal climate variability on timescales of decades.”
Mann, Byron A. Steinman, assistant professor of geological sciences, University of Minnesota-Duluth and a former Penn State National Science Foundation postdoctoral fellow and Penn State researcher Sonya K. Miller looked at a combination of real-world observational data and state-of-the-art climate model simulations used in the most recent report of the Intergovernmental Panel on Climate Change to understand the competing contributions to climate variability in the Northern Hemisphere during the historic era. They report their results today (Feb 26) in Science.
The Atlantic Multidecadal Oscillation (AMO) describes how North Atlantic sea-surface temperatures tend to oscillate with a periodicity of about 50 to 70 years. The Pacific Decadal Oscillation (PDO) varies over a broader range of timescales. The researchers looked only at the portion of the PDO that was multidecadal — what they term the Pacific multidecadal oscillation (PMO).
Using a wide variety of climate simulations, the researchers found that the AMO and PMO are not significantly correlated; they are not part of the global “stadium wave” oscillation, as some researchers had claimed. What they found was that the Northern Hemisphere was warming more slowly, not because of the AMO — which has been relatively flat — but because of a sharply down-trending PMO.
The researchers conclude that the down-trending PMO and the unusual slowing of warming over the past decade are tied to heat burial beneath the tropical Pacific and a tendency for sustained La Niña type conditions. While there is paleoclimate data suggesting that this type of response could come from subtle features of climate change itself that climate models do not currently capture, the researchers note that the most likely explanation is the random excursions of the AMO.
“Our findings have strong implications for the attribution of recent climate changes,” said Mann. “Internal multidecadal variability in Northern Hemisphere temperatures likely offset anthropogenic warming over the past decade.”
The researchers conclude that given past historical patterns of variation in the AMO and PMO, this situation will likely reverse and add to human induced warming in the future.
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I see nothing inconsistent with natural variation.
The Mann admits to natural climate variability. Well, that’s a start. Er, maybe it’s ALL natural variation and we have little to do with it.
You mean natural climate variations overwhelm man made climate variations? Is that different from what the skeptics have been saying all along? And doesn’t that say something about how well the climate modelers can model natural climate variations?
Piltdown Mann
Using their numbers the human fraction of 0.85 degree C warming is 0.3 degree, In reality it is less than 0.1 degree, but in the publicity it becomes 1.0 degree?
Mann:
Total poppycock. It is VERY important here to keep in mind the chronology of Mann’s 1998 paper and the education of the world about the PDO and AMO. The PDO was discovered in 1997 by BIOLOGIST Steven Hare. In 1998 the PDO was basically not even on the radar of climatologists.
What does that chronology mean? That all of the “WE KNOW EVERYTHING ABOUT THE CLIMATE” statements of 1998 (and evena few years past) were totally igronant of the elephant in the room – the PDO.
AND YET, since they KNEW EVERYTHING at that time (1998), there was nothing else TO know. Human activity was the end all and be all of anything affecting the climate. Outside of humans the climate was FLAT. This was the main theme of Mann’s 1998 paper, after all – the basically flat climate until humans started putting extra CO2 into the air. THE PDO WAS NOT PART OF THAT AT ALL.
And, as is done in so many sciences, whenever a paradigm of any sort is overthrown, it only takes weeks for the involved scientitst to all run around claiming, “We knew that all the time!”
Ahh, the brazenness. Mann is NOW saying, “WE KNEW THAT ALL THE TIME!”
But, no, Señor Mann, you did NOT. And stop running around pretending that you did.
Oh, the Slick Willie-ness of this, Slick Mickey. Or is it Tricky Mikey?
Note that he refers to a flat trend for about 18 years as “warming more slowly”. AS IN DANG NEAR NEGATIVE WARMING, SLICK MIKEY? Or as in Zero sure is warming more slowly.
And no again, Slick Mikey. ASSERTING that there is heat missing when you have (at best) ambiguous evidence of such heat is pretty much lying. Claiming it is down where it can’t be found or not found – that is only a sneaky way of pretending something is true long before it is proven to exist. Nothing can be “tied to anything” when the “anything” itself hasn’t proven unambiguously to exist. And, no, you or Kevin Trenberth wanting it to exist doesn’t make it exist.
False pause? Well at least it is not a fake pause.
Mr. Mann it is a well proven fact that the missing heat can be found in Uranus.
Did these conditions also occur from 1880 until 1910 and 1940 until 1970 when previous pauses occurred?