Noah Diffenbaugh of Stanford is a well-known source of papers claiming alarming things about weather and climate. He churns out a paper about 2-3 times a year, with the typical bent of climate change is causing “X”. This one is no different. A few caveats:
Diffenbaugh only shows the worst photos with the press release, like these that were included:
What he won’t show you are photos like this one:
Thanks to Hank Hansen for the pictures. (via Kris Kuyper of Action News Now)
Or graphs like this one:
Here is the press release:
Atmospheric patterns linked with drought occurred more frequently in recent decades
NATIONAL SCIENCE FOUNDATION
Atmospheric scientists have found that California’s highest temperatures are almost always associated with blocking ridges, regions of high atmospheric pressure than can disrupt wind patterns – including one known as the Ridiculously Resilient Ridge. The Triple R, as it’s called, is also linked with California’s drought.
In new research published online this week in the journal Science Advances, a team of researchers led by Stanford University scientist Noah Diffenbaugh analyzed the occurrence of large-scale atmospheric circulation patterns that occurred during California’s historical precipitation and temperature extremes.
“Atmospheric circulation patterns are associated with various weather and climate events, ranging from flash floods caused by single-day downpours to multi-year, continent-wide droughts,” Diffenbaugh said.
Diffenbaugh, Stanford researcher Daniel Swain and other coauthors investigated whether atmospheric pressure patterns similar to those that happened during California’s historically driest, wettest, warmest and coolest years have occurred more frequently in recent years.
Implications for water resources, agriculture, energy
“Improved understanding of the drought in California has implications for water resources management, agriculture, hydropower and energy,” said Anjuli Bamzai, program director in the National Science Foundation (NSF) Division of Atmospheric and Geospace Sciences, which funded the research.
Bamzai said that while the region has recently experienced relief in snowfall and rainfall.
“The epic drought is far from over. These scientists show that the frequency of atmospheric circulation patterns that worsen drought conditions has increased over the long-term.”
The study focused on the northeastern Pacific Ocean and far western North America, encompassing the winter “storm track” region from which the vast majority of California precipitation originates.
The researchers used historical climate data from U.S. government archives to investigate changes during California’s rainy season, from October to May.
They identified the specific North Pacific atmospheric patterns associated with the most extreme temperature and precipitation seasons between 1949 and 2015. The analysis revealed a significant increase in the occurrence of atmospheric patterns linked with certain precipitation and temperature extremes over the 67-year period.
In particular, the scientists found increases in atmospheric patterns resembling what has happened during the latter half of California’s ongoing multi-year drought.
“California’s driest and warmest years are almost always associated with some sort of persistent high pressure region, which can deflect the Pacific storm track away from California,” said Swain. “Since California depends on a relatively small number of heavy precipitation events to make up the bulk of its annual total, missing out on even one or two of these can have significant implications for water availability.”
The “Ridiculously Resilient Ridge”
The scientists concluded that one such persistent ridge pattern was diverting winter storms northward and preventing them from reaching California during the state’s drought.
In 2014, the researchers published findings showing that the increasing occurrence of extremely high atmospheric pressure over this same part of the Northeastern Pacific is very likely linked with environmental change. But the group wanted to know whether the particular spatial pattern associated with the Triple R has become more common — a question not asked in the 2014 study.
The new study provides a more direct answer to this question. “We found that this specific extreme ridge pattern associated with the ongoing California drought has increased in recent decades,” Swain said.
Despite the fact that the number of very dry atmospheric patterns in California has increased, the number of very wet atmospheric patterns hasn’t declined.
“We’re seeing an increase in certain atmospheric patterns that have historically resulted in extremely dry conditions, and yet that’s apparently not occurring at the expense of patterns that have been associated with extremely wet patterns,” Swain said. “We’re not necessarily shifting toward perpetually lower precipitation conditions in California — even though the risk of drought is increasing.”
That might sound contradictory, but it’s not, the scientists say.
Imagine looking at a 10-year period and finding that two of the years are wet, two are dry, and the rest experienced precipitation close to the long-term average. Now imagine another decade with three very dry years, three very wet years, and only four years with near-average precipitation.
“What seems to be happening is that we’re having fewer ‘average’ years, and instead we’re seeing more extremes on both sides,” Swain said. “This means that California is starting to experience more warm/dry periods, punctuated by wet conditions.”
The role of temperature
Another important contributor to drought is temperature. Diffenbaugh previously found that higher temperatures during periods of low precipitation in California doubled the risk of drought.
The researchers also discovered that the long-term warming of California has substantially increased the number of hot years, thereby increasing the risk that low precipitation periods produce drought.
“The current record-breaking drought in California has arisen from both extremely low precipitation and extremely warm temperature,” Diffenbaugh said. “We found clear evidence that the extreme atmospheric pattern associated with these unprecedented warm and dry conditions has become more likely in recent decades.”
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I was struck by the almost absurd nature of Diffenbaugh et al’s position and the one represented by the Cook et al cartoon graphic. I found a recent Cook et al paper that appears to be the source of the latter. It appears to be a very thorough piece of analysis. I then checked to see how Diffenbaugh referenced Cook in his 2015 paper on unprecedented drought. One of his Cook references leads to the following paper. The key for me is that Cook comes to a similar conclusion IF he uses GCM based projections based on the 8.5 IPCC Scenario. Critiquing Diffenbaugh, therefore, requires a critique of GCMs and their projections.
http://advances.sciencemag.org/content/advances/1/1/e1400082.full.pdf?ijkey=0c572bd99f8c2cb4894d0aad814b445e2a8a1fce&keytype2=tf_ipsecsha
This itty bitty drought in California is not ‘unprecedented’ at all. There have been terrible long, 100 year long droughts in the past which is why so many plants and animals have evolved long, long ago, to deal with these drought conditions.
Another fact of life: nearly all trees in Los Angeles are alien transplants brought in since 1850. Virtually no one sees any native plants there and this includes tumble weeds which were brought in by settlers. They are not native, either, indeed, most ‘weeds’ are alien things brought in by humans who came in since 1900.
One of the native plants are greasewood bushes. That, and grasses of various sorts that have very deep roots and can survive long droughts. These are all called ‘weeds’ and ruthlessly uprooted when houses are built.
Bernie1815 – “… Based on the IPCC 8.5 scenario…”
Is there anybody left, even in climate science, that still believes that 8.5 is viable? Look at the sensitivity to CO2 in that scenario – I see no proof in any recent studies that 8.5 is plausible, yet the alarmists keep dragging it out when trying to support some improbable outcome. When I see a study based on an 8.5 model, it gets round-filed immediately.
So what would a 67 year span look like on this graph of swings that have likely affected Africa over the past oh, million years?
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4697375/figure/fig02/
People who study California with regard to 67 years are a bit childish and like to study miniature things.
Grown ups study this: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4697375/
Pamela,
Great citation, thanks. It does seem like science is being done in places, and this data-rich study seems an excellent example. Others will hopefully aspire higher, and if peer review actually worked, there’d be forced to.
We checked out Lake Shasta last weekend (20 minute drive from our home) and while it’s not quite brim full it’s pretty darn close. Lovely to see. It must really tick off the environazis who hate it when Mother Nature doesn’t listen to their stupid childish whining.
Most of the reservoirs are here.
http://cdec.water.ca.gov/reservoir_map.html
I’ve been watching them for some time.
Many have Facebook pages as well.
Campers and boaters are giddy. https://www.facebook.com/Shasta-Lake-273241804440/
There’s ongoing controversy over water dumping at Trinity Lake.
http://northtrinitylake.com/
“The Trinity Center ramp is usable down to about 2,295′, so the lake only has to come another 11′ to reach the bottom of the ramp. But they will start dumping the lake in late April or early May, so then the question will be if the snow melt can keep up with their aggressive dumping of the lake. Hopefully the Trinity Center ramp touches water for a least a few weeks.
The next week is critical — if we get much rain, the Bureau will declare this a “wet” year and dump the lake in May. Nominally, they make their determination on April 1, appropriately enough, but they won’t really announce it until after the TMC meeting April 6/7. However, the early word is that they are going to start dumping the lake down the river earlier in April this year than in recent years.
In a “wet” year, they dump about 62 feet of lake elevation down the river for their failed “restoration” project. This doesn’t count the water they send down the river for the “boat dance”, the “avoid-a-fish-kill-on-my-watch” dumping of the lake, the Humboldt 50,000 af “take”, or any other special interest group nonsense in August. In a “normal” year, the dump is about 56 feet. In “critically wet” years, the dump is 74 feet, in “dry” years (like 2015), the dump is 37 feet, and in “critically dry” years, it is 32 feet.
Of course, they dump an equal amount over the hill for Westlands Water District and more fish nonsense in the Sacramento. So double the above numbers to estimate how much they will take from the lake in total. Most of the fish dump occurs before, and early in, boating season.”
And Trinity Lake is not doing as well as the others.
http://cdec.water.ca.gov/cdecapp/resapp/resDetailOrig.action?resid=CLE
53% of Total Capacity
67% of Historical Avg. For This Date
maybe so, but are fossil fuel emissions to blame?
http://papers.ssrn.com/sol3/papers.cfm?abstract_id=2725743
“He churns out a paper about 2-3 times a year”. look, even ignoring the issue that this article is a bit unfair in giving Diffenbaugh ALL the credit/notoriety for what actually appears to be a paper written by his PhD student (the actual 1st author of the paper) if you are going to refer to their science, maybe you ought to at least do the math before belittling someone’s track record in public? Look, I appreciate that this is a blog. Anyone (particularly the blog owner/moderator) can write pretty much whatever comes into their head and expect that some will read it. I appreciate that, which is why I still come here hoping to glean something useful from the alternate views on vigorous debates that will hopefully lead (eventually) to some mutual acknowledgement that there is misinformation and misinterpretation happening on both sides. But my day job is as a scientist. Sure, not a climate scientist but part of my job still requires me to frequently assess other people’s research track records (usually in the context of job or grant applications). So I take issue with Anthony’s claim here . Call me part of a system that pays homage to worthless scientists if you like, but a cursory look at the Thomson ISI database (the “Web of Science” – the most ‘choosy’ of the scientific bibliographic databases ) lists 31 articles with Diffenbaugh as co-author in 2013-15. I make that at least 10 per year in recent years (and many of those in better journals than I’ve been able to manage publishing in). No doubt Google would list more…..
The last period where Negative PDO dominated was 1940ish – 1978. Far lower demand on water systems back then. Also, significantly, Pat Brown wisely fostered major water infrastructure improvements mid century. All the previous Negative PDO periods were back when almost no one was here, so N/A. Now we have another overall Negative period (I know, I know, some claim it flipped Positive for a few years more recently but the overall period since the beginning of the Century is negative). We are essentially in unknown territory – Negative PDO with no substantial infrastructure increase since the middle of the last century.