The rise in temperatures along the U.S. West Coast during the past century is almost entirely the result of natural forces — not human emissions of greenhouse gases, according to a major new study released today in the Proceedings of the National Academy of Sciences.
Northeast Pacific coastal warming since 1900 is often ascribed to anthropogenic greenhouse forcing, whereas multidecadal temperature changes are widely interpreted in the framework of the Pacific Decadal Oscillation (PDO), which responds to regional atmospheric dynamics. This study uses several independent data sources to demonstrate that century-long warming around the northeast Pacific margins, like multidecadal variability, can be primarily attributed to changes in atmospheric circulation. It presents a significant reinterpretation of the region’s recent climate change origins, showing that atmospheric conditions have changed substantially over the last century, that these changes are not likely related to historical anthropogenic and natural radiative forcing, and that dynamical mechanisms of interannual and multidecadal temperature variability can also apply to observed century-long trends.
From a Seattle Times newspaper story: (h/t Dale Hartz)
The vast majority of coastal temperature increases since 1900 are the result of changes in winds over the eastern Pacific Ocean, the authors found. But they could find no evidence that those weather patterns were themselves being influenced by the human burning of fossil fuels.
…
Since the ocean is the biggest driver of temperature changes along the coast, the authors tracked land and sea surface temperatures there going back 113 years. They found that virtually all of the roughly 1 degree Celsius average temperature increase could be explained by changes in air circulation.
“It’s a simple story, but the results are very surprising: We do not see a human hand in the warming of the West Coast,” said co-author Nate Mantua, with NOAA Fisheries Southwest Fisheries Science Center. “That is taking people by surprise, and may generate some blowback.”
Source: http://seattletimes.com/html/localnews/2024601865_climateweatherstudyxml.html
The paper:
Atmospheric controls on northeast Pacific temperature variability and change, 1900–2012
James A. Johnstone and Nathan J. Mantua
Abstract
Over the last century, northeast Pacific coastal sea surface temperatures (SSTs) and land-based surface air temperatures (SATs) display multidecadal variations associated with the Pacific Decadal Oscillation, in addition to a warming trend of ∼0.5–1 °C. Using independent records of sea-level pressure (SLP), SST, and SAT, this study investigates northeast (NE) Pacific coupled atmosphere–ocean variability from 1900 to 2012, with emphasis on the coastal areas around North America. We use a linear stochastic time series model to show that the SST evolution around the NE Pacific coast can be explained by a combination of regional atmospheric forcing and ocean persistence, accounting for 63% of nonseasonal monthly SST variance (r = 0.79) and 73% of variance in annual means (r = 0.86). We show that SLP reductions and related atmospheric forcing led to century-long warming around the NE Pacific margins, with the strongest trends observed from 1910–1920 to 1940. NE Pacific circulation changes are estimated to account for more than 80% of the 1900–2012 linear warming in coastal NE Pacific SST and US Pacific northwest (Washington, Oregon, and northern California) SAT. An ensemble of climate model simulations run under the same historical radiative forcings fails to reproduce the observed regional circulation trends. These results suggest that natural internally generated changes in atmospheric circulation were the primary cause of coastal NE Pacific warming from 1900 to 2012 and demonstrate more generally that regional mechanisms of interannual and multidecadal temperature variability can also extend to century time scales.
http://www.pnas.org/content/early/2014/09/16/1318371111.abstract
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It’s not just US West Coast. It’s global. There’s good correlation between PDO and global temperature in 20th century (Spencer, 2010)
Which is why the authors probably had to resort to the PNAS good-ole-boy network to get their paper published. Likely Nature journals and Science rejected because it upsets the dogma and climate cognoscenti.
The careful read and consideration of what they propose, even though they try to assuage Climate Change warmists, shows that these results argue the anthropogenic CO2 signal is being swamped by internal dynamical variability of the climate system over the world’s largest ocean. If the PDO pushes its effects global (and it does), then by extension, the anthropogenic signal is being swamped everywhere by dynamical variations.
This implicitly argues two things.
1) Climate change is unpredictable, and beyond the reach of computers and models to predict beyond half of a typical (aperiodic) PDO cycle (15-25 years), much less a full century.
2) no amount of anthropogenic CO2 reduction can measurably alter a Climate Change when that signal is already operating at nearly system noise levels.
“… the anthropogenic signal is being swamped everywhere by dynamical variations.”
Why this is not obvious to any sane rational person, but especialy scientists, is one of the great mysteries of the world, perhaps usurping the mystery of immaculate conception.
Could have saved a lot of taxpayer’s hard earned cash by buying Bob Tysdale”s book and republishing it.
That certainly would have made Bob some money. How much has Bob made off of the climate deniers conspiracy?
By my calcs, about 0.005% of how much Pope AlGore has made off of hockey sticks and MidEast sheikh oil money.
I am an optimist and just hope this is the first hint of a new climate science day revealing the bogey men for the imaginary monsters they are. The beginning of the end for souffle science?
My only question is when is Gore tar and feathered and run out of town on a donkey.
why waste a good donkey?
This is the answer to wriggle matching and number crunching. Get passed the numbers and start figuring out the mechanism. Leif and others have been working nonstop to deduce solar mechanisms behind the 11 year cycle and larger trends up and down. While that was in its infancy, others in the solar field continued to study just the numbers and make predictions on just the numbers. We all know how that ended up.
The present study is following in the footsteps of Leif and others. Let’s figure out the mechanism instead of basing a wild ass guess on numbers and trends. The West Coast is clearly affected by oceanic-atmospheric teleconnected processes and this paper takes a good stab and working that out.
So do the same thing with sea ice. Stop tearing your hair out scientists and beating your back with chains (a religious ceremony to bemoan some kind of bad thing) and do what Leif et al. and the present authors of this paper have and are doing. Observe the oceanic-atmospheric teleconnected conditions that were present before and during Arctic ice trends then set up a model (CO2 and solar trends need not apply) to see if your conditions will cause sea ice trends. My hypothesis is that they will. But beware of such a hypothesis. You should approach the problem trying to prove that they won’t.
Alarmism is on its last legs. We may have, we meager lowly armchair hobby scientists, wrangled good science back out of the trash heap so enthusiastically thrown out by grant-grubbing psudo-scientists, and torn away the itchy wool universally pulled down upon the peoples of Earth by the same greedy rent-seeking bastards who need to be pink slipped ASAP.
Oh, Pamela, how I wish you were so right about alarmism being on its last legs. But given Barack the Usurper’s speech at the UN today and all of the hysterics and demonstrations taking place over the last few days, the alarmists don’t seem to want to go away. Someone is going to have to swat them down soon. But I remain somewhat pessimistic. Let us hope that all this recent activity is merely the dying gasp of a sinister power-grab movement.
Seattle Times: “They also noted that the wind changes consistently preceded the ocean surface temperature variations by about four months, showing the wind was causing the changes to temperature, not the other way around.”
This exactly what I’ve been saying, and what regional surface temps show, when you don’t mash them all together. Follow the link in my name to see what the real surface temps show.
Even the LA Times carried this article today. The first piece from them contrary to AGW in years.
How many regional stories and models does it take to make a globe?
James Johnstone will have to be placed in a witness protection program for his own safety.
http://www.climatecentral.org/news/west-coast-warming-natural-variability-18067?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+climatecentral%2FdjOO+Climate+Central+-+Full+Feed
The Warmists are ready to deploy the “yeah, but we’re still right” defenses.
“But, “this is not to say global warming is nonsense,” he added. As greenhouse gas levels continue to rise, Mass expects humanity’s greenhouse gas pollution to play a growing role in fiddling with the region’s thermostats.
“In certain places, natural variability is extremely large compared to the anthropogenic signal,” he told Climate Central. “That’s not going to necessarily be true in 50 or 100 years. The anthropogenic signal is going to amplify in time.””
So, just give it another 50 or 100 years, then we’ll see who’s right!
If it weren’t for these damned ‘Oscillations’ …
MinTruth needs to get on to that.
GregK September 22, 2014 at 6:02 pm
Lack of evidence certainly does not mean that human C02 emissions are not the root cause of this change in climate.
Similarly it does not mean that the prevalence of black cats, witches, surfers or cafes with good coffee are not the cause either.
Ah the fatal flaw in the analysis is to compare the presence of witches ….. — Because while witches often correlate with black cats [e.g. Salem MA during the week before November 1 ] — only surfers correlate both with both the coastal Mediterranean Climate and cafes by the sea shore with good coffee — e.g. Santa Monica, Seattle but not Salem — note the correlation doesn’t seem to be with cities whose names begin with the letter S either,
@WestHighlander September 23, 2014 at 2:39 pm”
Riddle me this. If there is no evidence, none and you acknowledge such, then what is the basis for belief?
The most important part of that abstract is the last sentence, in which the authors of the paper appear to confirm that variations between localities and regions can occur even on a long term scale as well as short term. What implications does this have for the idea that we can easily generalize about or make sensible conclusions about a “world-wide” temperature or a “world-wide” CO2 effect?
Pamela, I could not agree more that climate scientists should look at a broader range of fields other than CO2 science. However I still see a solar/climate link. If you are interested, print these two graphs.
http://sidc.oma.be/silso/monthlyhemisphericplot——the solar hemispheric bias
http://www.skepticalscience.com/Pacific-Decadal-Oscillation.htm—– the running mean of the PDO from the university of Washington data.
shrink/ expand/superimpose/whatever. If you cant see any link then I probably need a pair of glasses!
Then remember that due to the solar axial inclination, the Antarctic tends to face the northern hemisphere of the sun during the latter half of the ice-build cycle. Opposite for the arctic.
Sorry I have no idea how to do links–my bad
That’s okay. If you can’t find the link, why continue to dig for it? LOL!
I think observations alone right here on Earth adequately describes the pseudo-random nature of weather and the somewhat oscillatory behavior of weather pattern changes and trends. Of all the mechanisms capable of storing incoming solar heat and belching it back out again in patterns that predict these land temperature and weather trends, the oceans rise to the top.
Note to alarmists: Now don’t go all panicky into the streets saying that I said oceans are rising to the top.
Addendum to my comment related to your solar axial inclination. Axial tilt is an Earth sourced intrinsic driver. The sun doesn’t tilt, we do.
Thanks for getting back Pamela. I was merely trying to show a solar /PDO link. The inclination of the earth was noted to highlight that sea-ice gain/loss could be related to the strength of the solar wind from whichever solar hemisphere each pole is in during the latter half of sea-ice formation, indeed I think that the recent loss of arctic sea-ice is related to the strong southern solar hemisphere over the last 35-40 years. Thanks again.
Try these
http://www.skepticalscience.com/Pacific-Decadal-Oscillation.htm
http://sidc.oma.be/images/wnosuf.png