California Drought – A Novel Statistical Analysis of Unrealistic Climate Models and of a Reanalysis That Should Not Be Equated with Reality

Guest post by Bob Tisdale

UPDATE: See the update at the end of the post.

In the post The Obvious Failures of Climate Science That Mainstream Media Ignores, I promised to discuss the paper behind the National Science Foundation press release Cause of California drought linked to climate change. That paper was Swain et al. (2014) “The Extraordinary California Drought of 2013/2014: Character, Context and the Role of Climate Change”. It is included in the Special Supplement to the Bulletin of the American Meteorological Society (BAMS report) Vol. 95, No. 9, September 2014, Explaining Extreme Events of 2013 From A Climate Perspective.

Swain et al. (2014) begins:

California’s driest 12-month period on record occurred during 2013/14, and although global warming has very likely increased the probability of certain large-scale atmospheric conditions, implications for extremely low precipitation in California remain uncertain.

Basically, Swain et al. (2014) are saying that human-induced global warming increased the likelihood of the atmospheric conditions that caused the 2013/14 drought, but they have no idea what will happen in the future.

The NSF press release provides a brief overview of the Swain et al. (2014) (my boldface):

Climate scientist Noah Diffenbaugh of Stanford University and colleagues used a novel combination of computer simulations and statistical techniques to show that a persistent region of high atmospheric pressure over the Pacific Ocean–one that diverted storms away from California–was much more likely to form in the presence of modern greenhouse gas concentrations.

A “novel combination of computer simulations and statistical techniques”?

Let’s see, looking at the paper, Swain et al. used climate models stored in the CMIP5 archive, but those models have no bases in reality. The models stored in the CMIP5 archive cannot simulate (hindcast) global or regional surface temperatures or precipitation. We discussed and illustrated those failings in a series of posts in 2013 in advance of the IPCC’s 5th Assessment Report. Topics discussed included:

Those posts were also cross posted at WattsUpWithThat. And I expanded on that series and presented the model faults in my book Climate Models Fail.

Swain et al. also used a reanalysis (computer model that has data as inputs). But a reanalysis is not reality. It is not the same as observations-based data. It’s a specialized climate model.

The National Center for Atmospheric Research (NCAR) presents the limitations of reanalyses at the end of the Summary of their webpage titled Atmospheric Reanalysis: Overview and Comparison Tables. There they write (my boldface):

Key Limitations:

  • Reanalysis data sets should not be equated with “observations” or “reality”
  • The changing mix of observations, and biases in observations and models, can introduce spurious variability and trends into reanalysis outpu
  • Observational constraints, and therefore reanalysis reliability, can considerably vary depending on the location, time period, and variable considered

Yet Swain et al. treated the reanalysis they used as if it represented reality.

Out of the more than 3 dozen climate models stored in the CMIP5 archive, Swain et al. (2014) cherry-picked 3 (GISS-E2-H, HadGEM2-ES, NorESM1-M) for their study.

We discussed the recent high sea surface temperatures in the eastern extratropical North Pacific in the post On The Recent Record-High Global Sea Surface Temperatures – The Wheres and Whys. Figure 1 is Figure 15 from that post. The eastern extratropical North Pacific is the region with the recent persistent hot spot that contributed to the California drought. That region of the North Pacific cooled, not warmed, based on the linear trend from January 1989 to December 2012. That’s almost 2.5 decades where the sea surface temperatures cooled, before the unusual upswing.

Figure 1

Figure 1

And even with the addition of the most recent data, Figure 2, the sea surface temperatures of the eastern extratropical North Pacific show no warming since January 1989, based on the linear trend. (That was Figure 16 in the earlier post.)

Figure 2

Figure 2

We also showed in that post that the sea surfaces of the North Pacific as a whole had not warmed from January 1989 to December 2012, the year before the unusual warming episode. Figure 5 from that post is shown below in Figure 3.

Figure 3

Figure 3

Let’s take a look at how well the models simulated those absences of warming. Wanna guess?

According to the models selected by Swain et al (2014), the surfaces of the eastern extratropical North Pacific should have warmed more than 0.65 deg C from January 1989 to July 2014 if they were warmed by manmade greenhouse gases. That’s based on an unrealistic warming rate of more than 0.25 deg C/decade. See Figure 4. But, as shown above in Figure 2, based on the linear trend of the data, they didn’t warm.

Figure 4

Figure 4

And as shown in Figure 5, based on the models selected by Swain et al., the surfaces of the North Pacific as a whole should have warmed more than 0.60 deg C from January 1989 to December 2012 if they were warmed by those nasty little manmade greenhouse gases. But once again, referring to Figure 3, based on the linear trend of the data, there was no warming.

Figure 5

Figure 5

It’s tough to employ climate models so you can claim that manmade greenhouse gases caused the California drought, when the models used by Swain et al. can’t simulate the lack of warming of one of the key metrics associated with it.

In summary, Swain et al. performed “novel” statistical techniques on dubious climate models and on a reanalysis that should “not be equated with ‘observations’ or ‘reality’”. Swain et al. also failed to note or consider that the sea surface temperatures of the eastern extratropical Pacific cooled from 1989 to 2012 and that the North Pacific as a whole showed no warming for that same time period, while the climate models they employed showed the oceans warming drastically during those periods.

And some people wonder why climate skeptics are skeptical of climate science.

SOURCE

The Reynolds OI.v2 sea surface temperatures and the outputs of the CMIP5-archived models used by Swain et al. are available through the KNMI Climate Explorer.

UPDATE

Based on a comment on the thread of the cross post of this article at my blog Climate Observations, some persons might be wondering why I compared models of sea surface temperature to data, when Swain et al (2014) focused on geopotential height (see note below). My reply:

The large scale atmospheric circulation patterns are in part dependent on local sea surface temperatures. The oceans and atmosphere are coupled. If the models cannot simulate the sea surface temperatures properly, then they are not simulating atmospheric circulation properly.

Let’s confirm that.

Lead author Swain also wrote an article for The California Blog at WeatherWest titled Special update: The Extraordinary California Drought of 2013-2014: Character, Context, and the Role of Climate Change. In it, he acknowledged the relationship between ocean and atmosphere a number of times. On page 2 of his article, Swain wrote (my boldface):

Several recent studies have examined precisely this possibility in assessing cause of the extraordinary persistence of the Ridiculously Resilient Ridge in 2013 and 2014. Wang et al. (2014) find that tropical West Pacific SST warm anomalies (associated with the West Pacific Warm Pool that acts as a precursor of El Niño) played a leading role in causing the strength and longevity of the Triple R by generating a recurring series of atmospheric “Rossby waves” that propagated from west to east across the Pacific Basin. Wang and Schubert (2014) find that the North Pacific SST warm anomalies during early 2013 created a “predilection” for dry conditions during the second half of the 2013-2013 “rainy season” in California, and Funk et al. (2014) also report that the observed Pacific SST anomalies during 2013-2014 contributed to the extremely low precipitation that was observed during 2013-2014.

However, Funk et al. also note that it’s possible the record-breaking warmth in the North Pacific (discussed further below) was actually a geographically remote response to the changes elsewhere in the Pacific–similar to the mechanism considered by Wang et al. It’s even possible that that the Triple R played a role in sustaining itself by reducing North Pacific storm activity and preventing vertical mixing of cooler sub-surface ocean water, culminating in a self-reinforcing feedback loop by which atmospheric ridging led to warm SSTs , which in turn led to more ridging, and so on. Regardless of whether the record-breaking warmth in the North Pacific was the primary cause of the Triple R or merely a secondary one, it’s pretty clear that Pacific SST anomalies contributed to the persistent northeastern Pacific ridging and extremely low California precipitation observed in 2013-2014.

Swain confirmed that the sea surface temperatures of the eastern extratropical North Pacific and atmosphere above it are interrelated, and that the warm sea surface temperatures contributed to the California drought.

Looking back now at my post above, Figures 1 and 2 showed that the sea surface temperatures of the eastern extratropical North Pacific had not warmed for 2.5 decades, and had cooled prior to the unusual warming…while the climate models employed by Swain et al, Figure 4, showed the sea surface temperatures of that region should have warmed more than 0.65 deg C in those 2.5 decades if they were warmed by manmade greenhouse gases.

In other words, the climate models employed by Swain et al are not realistic representations of climate in the eastern extratropical North Pacific. This further indicates they have no value when attempting to determine the cause or causes of the California drought, and no values when trying to attribute that drought to manmade factors.

Note: If the term geopotential height is new to you, see the ECMWF webpage here.

 

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Just a quibble on the last sentence…. We may be skeptical of a lot of the climate science we see… But I am not sure that we are ‘climate skeptics’.

johnmarshall

Most of us know that climate changes, always has it is the cause that is the problem and that is not CO2.

latecommer2014

I wonder that they’d imply that greenhouse gas could warm the oceans.

schitzree

I prefer the term CAGW Skeptic. Catastrophic Anthropogenic Global Warming. I usually pronounce it the same as Kaiju.
Because Godzilla has just as much chance of rising from the ocean depths and destroying us as Trenberth’s missing heat.

I think this is a very important point. We represent climate science, not climate politics. The use of propaganda terminology intended to discredit valid science is buying into the disinformation campaign promoted by frauds like Michael Mann, John Cook and the IPCC. We’re climate scientists; they’re climate politicians. We’re not deniers – we acknowledge that AGW-alarmism is a man-made concept, and we don’t deny that climate change is a political issue. I think it’s important to make a serious effort to adopt a positive description for supporters of valid climate science rather than adopting disinformation terminology.

Bloke down the pub

Just as long as they don’t try selling me an investment based on that sort of projection.

johnmarshall

Your usual good analysis of a non problem. Thanks Bob.
How long have we all been saying that climate models are based on the wrong assumptions?

joelobryan

The CA drought is definitely a very serious problem, and not just for Cal. Anyone in N. America who likes to eat fruits and vegetables are being impacted.
CO2 though at 400ppm in no honest way can be implicated as a casual factor. CO2 is the non-problem.

Twobob

Disney altered the fairy tales too.

Admad

http://youtu.be/-0BAh-n1_j8
“Swain et al. also used a reanalysis (computer model that has data as inputs). But a reanalysis is not reality. It is not the same as observations-based data. It’s a specialized climate model.
The National Center for Atmospheric Research (NCAR) presents the limitations of reanalyses at the end of the Summary of their webpage titled Atmospheric Reanalysis: Overview and Comparison Tables. There they write (my boldface):
Key Limitations:
Reanalysis data sets should not be equated with “observations” or “reality””

Gary Pearse

Why didn’t they use the observed temperatures? Do they explain? It is clear from the model they used that it needed a lot of novel statistics and reanalysis though.

Just an engineer

“And some people wonder why climate skeptics are skeptical of climate science.” would be more accurately stated
And some people wonder why “climate science” skeptics are skeptical of “climate science”.

ColA

And some people wonder why “climate science” skeptics are skeptical of “climate science”. would be more accurately stated
And some people wonder why “climate science” skeptics are so skepital of “CAGW climate scientists”

The other Ren

Bob – Please stop writing articles and essays with facts in them. It is totally unprofessional.

njsnowfan

Good post Bob.
A chart I pit together in July Lake Mead and PDO.
https://mobile.twitter.com/NJSnowFan/status/518023048415694848/photos
Alas, You mad a chart (not sure when) that someone poster on twitter with Sun spot number and PDO.
I found it very interesting how solar and PDO did opposites with strong cycles and they tracked close together during low solar like now.
With this cycle #24 only going to get weaker in time(Max is over and PDO spiked to positive) the PDO should continue to track solar and go negative again soon. That being said if next solar cycle#25 is low or lower like #24 CA and SW may be in some very longer drought times ahead?

Tom O

You can “try” to track Lake Meade water levels against anything you want, but unless you are factoring OUT the effects of population change, there is nothing you can show that will have any basis in reality. To tie the fluctuation in levels, especially the decline, to sunspots, the PDO, or CO2 is pointless. There are many “manmade” effects on climate, population growth and land stewardship being the most important, but how much gas we exhale – through either end – isn’t one of the ones that matter.

Cinaed Simson
LogosWrench

I would agree the California drought was caused by humans but not climate change but rather insane human caused policies with respect to water use and storage but instead of dealing with systemic policy issues, governor moonbeam is banning plastic bags.
Typical.

Newly Retired Engineer

Folks,
We need to kill this “banned plastic bags” canard – the bill bans one-time-use plastic bags, to be replaced with multi-use plastic bags over the next 15 months or so (with a subsidy to California plastic bag manufacturers to re-tool). And it requires charging for paper bags. In no way did the State of California “ban plastic bags”. We have some pretty loony policies here, but this just isn’t one of them.

Why does CA have to subsidize reuseable plastic bags when the one we now get are generally perfectly useable. Granted, sharp-cornered boxes or other containers sometimes poke a hole, but most times a “used” plastic grocery bag can be reused several times already.

With no plastic grocery bags, what am I going to use in my small wastebaskets – especially in the bathroom – re-useable bags?

schitzree

Got it, Moonbeam didn’t ban plastic bags. He banned CHEAP plastic bags. Then he gave money to plastic bag manufacturers to help them make EXPENSIVE plastic bags (with more plastic in them) that mostly won’t be reused anyway. Oh, and he made paper bags less affordable to insure we use the expensive plastic bags.

earwig42

As usual, clear,concise and honest. Thanks Bob.

Jimbo

Perspective. Here are US droughts and mega-droughts during the Holocene. megadroughts
worldwide happened in the past, will happen now and will continue to happen. This drought is just that. Nothing unusual and no evidence it’s been made worse by man’s greenhouse gases. It is pure speculation.
Here is what the IPCC observes.

IPCC
IPCC Fourth Assessment Report: Climate Change 2007
Multiple proxies, including tree rings, sediments, historical documents and lake sediment records make it clear that the past 2 kyr included periods with more frequent, longer and/or geographically more extensive droughts in North America than during the 20th century (Stahle and Cleaveland, 1992; Stahle et al., 1998; Woodhouse and Overpeck, 1998; Forman et al., 2001; Cook et al., 2004b; Hodell et al., 2005; MacDonald and Case, 2005). Past droughts, including decadal-length ‘megadroughts’ (Woodhouse and Overpeck, 1998), are most likely due to extended periods of anomalous SST (Hoerling and Kumar, 2003; Schubert et al., 2004; MacDonald and Case, 2005; Seager et al., 2005), but remain difficult to simulate with coupled ocean-atmosphere models. Thus, the palaeoclimatic record suggests that multi-year, decadal and even centennial-scale drier periods are likely to remain a feature of future North American climate, particularly in the area west of the Mississippi River.

Jimbo

Lets look at US drought now, 1934 and 1956. [Palmer Drought Index].
Can I hear “WE MUST ACT THEN!”
============
NOWcomment image
1934
http://stevengoddard.files.wordpress.com/2014/10/screenhunter_3260-oct-03-00-04.gif?w=640&h=496
1956comment image

Barry

Bob, if you read Chapters 3 and 4 of the BAMS report, they both indicate that the CA drought cannot be attributed to the long-term warming trend, which seems to align with your argument. The Swain et al. paper, though, does not make a case based on sea surface temperatures, but rather geopotential height and wind anomalies (the high pressure ridge).

Doug Proctor

Paul Ehrlich is a walking testament to the lack of accountability in the eco-green movement. Say what you will, if ut is for the Cause, you will get a pass on how things really are.
There is no accountability, but there is fame and money. We’ll never be free of these agitators until the likes of Al Gore are an embarrassment and grants for CO2-based funding ends.

In philosophical terms, the conclusion of the argument that is made by the paper of Swain et al is reached by application of the fallacy of misplaced concreteness. To be guilty of this fallacy is to reify (make real) an abstract object by treating it as if it were a concrete object.

wally

Why read a BAMS report when we have this?:
http://ecowatch.com/2014/10/02/tree-falls-forest-michael-mann-climate-change/2/
“The real problem is the lack of humility among some scientists when it comes to evaluating the potential impacts that climate change may be having on our environment. “

Great post, Bob, with good detailed analysis.
For those interested in the California drought, I have also done a (very simple) post regarding *actual* precipitation in the Northern Sierra region, available here:
http://climatereflections.wordpress.com/2014/09/30/northern-sierra-annual-precipitation-update-through-2014/

For a person wishing to know the likelihood of multiyear droughts in California it would be worth the effort to track down and read the final report of a study performed by Ron Christensen et al of Entropy Limited circa 1980. Using an information theoretically optimal pattern matching model it was found possible to predict whether a water-year would be wetter or dryer than average 1 to 3 years in advance. The Office of Water Research and Technology Contract number was 14-34-001-8409.

Pamela Gray

Current AGW climatologists are just like teenagers. No matter how many generations of teenagers have shown clear evidence of poor decision making skills compared to later in adult life, the current generation of teenagers think they know everything and have the wisdom of Job. History has no place in their brains.
After this California drought goes away the hordes of panicky scientists will too. Until the next drought comes along. At that point the current crop of AGW climatologists will once again be walking the hallowed halls of the Ivory Tower with tall signs saying the World Will End Lest We Repent. History has no place in their brains.

TRM

That is where a parent lovingly smacking them upside the head and saying “what were you thinking dumbass?” is so crucial to their long term development. It worked for me, both ways! 🙂

jmorpuss

Quoted by someone ” You’ll never know were your going if you don’t know were your been”

After the drought ends we will be able to say that carbon dioxide ended the drought, why not.

I think of it as Climate Reality And Programs effort by the mainstream scientific community… if the acronym fits…???? Wear it!

Henry Bowman

A “novel combination of computer simulations and statistical techniques”?

Most people call that “making it up”.

Francisco

Back in the day (school) I would only plot all the know data and see if I could get a trend. What can be wrong with that here? we can’t get it any more wrong than the models, can we? (has anybody tried this? if not I call dibs!)

As an approach to building a model, curve fitting leaves a lot to be desired. Usually it mates up poorly with logic. A consequence from using it is to be unable to provide logical support for the model’s conclusion.

pat

BBC had Daniel Swain on World Service Radio last nite, but not documented yet. however, this headline is reminiscent of The Independent’s headline back in 2000 – ” Snowfalls are now just a thing of the past”:
29 Sept: BBC Earth: Is this the end of autumn as we know it
Catch this year’s autumn leaf spectacle, because it may not be back
Presented by Stephanie Pappas
http://www.bbc.com/earth/story/20140929-why-is-autumn-changing

RHL

The California Drought Web page has a link to this study on their bi-weekly drought report.
http://ca.gov/drought/pdf/Weekly-Drought-Update.pdf
where it states: “Historic California Drought Linked to Global Warming: A new study released on Monday, September 29, by Stanford University climate scientists states that the conditions contributing to the historic drought in California are “very likely” linked to human-caused climate change. The study was published as a supplement to this month’s issue of the Bulletin of the American Meteorological Society which is one of the most comprehensive studies to investigate the link between climate change and California’s ongoing drought.”
Once again, the state trumpets the AGW narrative at every opportunity.

Here’s an interactive map of CA dams. Maybe they can be utilized better the next time it rains.
As the song goes: “It never rains in California, but the girls, all they warn you – it pours, man it pours”:
http://www.kqed.org/news/science/climatewatch/waterandpower/map.jsp

stas peterson

Governor Moonbeam and his DEMOC-gogues have banded together with the Green Watermelons to knock down Dams and empty water impoundments.
They said, in the then wet years, they were un-necessary, completely ignoring why the reservoirs were constructed anticipating dry years. In short, typical shortsighted thinking and merely rushing to be in front of the unthinking mob, so they can pretend to lead it.
Now we have the inevitable dry years, and judging by the historic Sierra precipitation records, not all that dry in reality. But some communities actually have no water, and the list grows.
In a normal democracy these proven idiots would be pre-emptorily “retired” from Office and in some cases “tared and feathered”. Instead they re-inforce the stupidities with CARBite over each; and over wrought concern for some non-native minnows.
I pine for the good old days.

jmorpuss

Bob , Have you looked into this ,http://en.m.wikipedia.org/wiki/Ground_dipole
And what sort of atmospheric and ocean leakage takes place when man abuses this process?

what, What, WHAT???

barchester

The California drought is primarily caused by the Pacific Decadal Oscillation. The West Without Water, B.L. Ingram et al.

Proud Skeptic

“California’s driest 12-month period on record occurred during 2013/14, and although global warming has very likely increased the probability of certain large-scale atmospheric conditions, implications for extremely low precipitation in California remain uncertain.”
Since when is “has very likely increased the probability” science? Hey, Armstrong, Aldren and Collins…the changes made to the Apollo space capsule atmosphere “has very likely increased the probability” that there will be no more fires like with Apollo 1.
Bon voyage! Hope things work out for ya!
Pathetic

CRS, DrPH

Basically, Swain et al. (2014) are saying that human-induced global warming increased the likelihood of the atmospheric conditions that caused the 2013/14 drought, but they have no idea what will happen in the future.

….in other words, the science is settled.
Thanks, Bob!

Lars P.

I found this post about a month ago:
http://www.zerohedge.com/news/2014-09-06/west-without-water
It shows that in the past the droughts have been more severe – with a warning that it may get even worst, no need for global warming to do that:
“Dr. B. Lynn Ingram is a professor in the Department of Earth and Planetary Science at UC Berkeley, California. The primary goal of her research is to assess how climates and environments have changed over the past several thousand years based on the geochemical and sedimentologic analysis of aquatic sediments and archaeological deposits, with a particular focus on the US West.
She is the co-author of “The West without Water: What Past Floods, Droughts, and Other Climatic Clues Tell Us about Tomorrow” together with Dr. Frances Malamud-Roam, which received great reviews
L. Ingram: “My co-author and I decided to write this book because our findings, and those of our colleagues, were all showing that over the past several thousand years, California and the West have experienced extremes in climate that we have not seen in modern history – the past 150 years or so . Floods and droughts far more catastrophic than we can even imagine. We felt it was important to bring these findings to the attention of the broader public, as these events tend to repeat themselves. So we need to prepare, just as we prepare for large earthquakes in California.”