UPDATE: Even Trenberth is critical of the Cai et al. (2013) study. See the update at the end.
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My apologies to the writers of Mel Brooks’ Blazing Saddles for the title of the post.
Hedley Lamarr: My mind is aglow with whirling, transient nodes of thought careening through a cosmic vapor of invention.
Hedley Lamarr: “Ditto?” “Ditto,” you provincial putz?
Blogger “Andrew” advises that the twitter-sphere is filled with discussions of a new paper claiming that the strengths of the late 20th Century El Niño events were caused by global warming. This argument has been around for years and keeps getting resurrected. Blogger “nevket240” provided a link to the Sydney Morning Herald article by Tom Arup Major El Nino events likely to double in next century, which appears to have initiated the discussions.
The new paper is Cai et al (2013) Increasing frequency of extreme El Niño events due to greenhouse warming. The abstract reads:
El Niño events are a prominent feature of climate variability with global climatic impacts. The 1997/98 episode, often referred to as ‘the climate event of the twentieth century’, and the 1982/83 extreme El Niño, featured a pronounced eastward extension of the west Pacific warm pool and development of atmospheric convection, and hence a huge rainfall increase, in the usually cold and dry equatorial eastern Pacific. Such a massive reorganization of atmospheric convection, which we define as an extreme El Niño, severely disrupted global weather patterns, affecting ecosystems, agriculture, tropical cyclones, drought, bushfires, floods and other extreme weather events worldwide. Potential future changes in such extreme El Niño occurrences could have profound socio-economic consequences. Here we present climate modelling evidence for a doubling in the occurrences in the future in response to greenhouse warming. We estimate the change by aggregating results from climate models in the Coupled Model Intercomparison Project phases 3 (CMIP3; ref. 10) and 5 (CMIP5; ref. 11) multi-model databases, and a perturbed physics ensemble. The increased frequency arises from a projected surface warming over the eastern equatorial Pacific that occurs faster than in the surrounding ocean waters, facilitating more occurrences of atmospheric convection in the eastern equatorial region.
A REANALYSIS CONTRADICTS THE MODELS
These are similar to the claims in Power et al. (2013) Robust twenty-first-century projections of El Niño and related precipitation variability. We discussed that paper in the post Will Global Warming Increase the Intensity of El Niño? To save myself some time, I’ll copy parts of that post:
However, Ray & Giese (2012) Historical changes in El Niño and La Niña characteristics in an ocean reanalysis found that El Niño events had not become stronger, or lasted longer, or occurred more often (among other things) since 1871. And manmade greenhouse gases are said to have caused global warming during that time period. The Ray & Giese (2012) abstract ends:
Overall, there is no evidence that there are changes in the strength, frequency, duration, location or direction of propagation of El Niño and La Niña anomalies caused by global warming during the period from 1871 to 2008.
So one wonders how climate models could simulate a future change in ENSO when there have been no changes in almost 140 years.
MODELS CAN’T SIMULATE BASIC ENSO PROCESSES
Additionally, we know climate models can’t simulate ENSO. Here’s another portion of that earlier blog post:
Because ENSO is the dominant mode of climate variability at interannual time scales, the lack of consistency in the model predictions of the response of ENSO to global warming currently limits our confidence in using these predictions to address adaptive societal concerns, such as regional impacts or extremes.
In other words, because climate models cannot accurately simulate El Niño and La Niña processes, the authors of Guilyardi et al. (2009) have little confidence in climate model projections of regional climate or of extreme events.
Bellenger, et al. (2013) “ENSO Representation in Climate Models: From CMIP3 to CMIP5,” is a more recent confirmation of how poorly climate models simulate El Niños and La Niñas. (Preprint copy is here.) The section titled “Discussion and Perspectives” begins:
Much development work for modeling group is still needed in order to correctly represent ENSO, its basic characteristics (amplitude, evolution, timescale, seasonal phaselock…) and fundamental processes such as the Bjerknes and surface fluxes feedbacks.
“Amplitude” refers to the strengths of ENSO events.
“Evolution” refers to the formation of El Niños and La Niñas and the processes that take place as the events are forming.
“Timescale” can refer to both the how long ENSO events last and how often they occur.
“Phaselock” refers to the fact that El Niño and La Niña events are tied to the seasonal cycle. They peak in the boreal winter.
“Bjerknes feedback,” very basically, means how the tropical Pacific and the atmosphere above it are coupled; i.e., they are interdependent, a change in one causes a change in the other and they provide positive feedback to one another. The existence of this positive “Bjerknes feedback” suggests that El Niño and La Niña events will remain in one mode until something interrupts the positive feedback.
In short, according to Bellenger, et al. (2013), the current generation of climate models (CMIP5: used by the IPCC for their 5th Assessment Report and by Power et al (2013)) still cannot simulate basic coupled ocean-atmosphere processes associated with El Niño and La Niña events–basic processes.
DATA CONTRADICT THE FLAWED MODELS
And, of course, to further contradict the models, ocean heat content data and satellite-era sea surface temperature data indicate ocean warming was caused by strong naturally occurring, sunlight-fueled El Niño events, not vice versa as claimed by the modelers…who still can’t simulate basic ENSO processes.
If the subject of the natural warming of the global oceans is new to you, refer to my illustrated essay “The Manmade Global Warming Challenge”(42MB). The way data portrays how the oceans warmed may come as a surprise to you, especially with all we’ve been told about human-induced global warming. If you like audio-video presentations, see my two-part YouTube video series “The Natural Warming of the Global Oceans”. Part 1 is here and Part 2 is here. Also see An Illustrated Introduction to the Basic Processes that Drive El Niño and La Niña Events.
And a whole lot more information about El Niño and La Niña can be found in my ebook Who Turned on the Heat? which has been lowered in price to U.S.$5.00. A free preview in pdf format is here. The preview includes the Table of Contents, the Introduction, the first half of section 1 (which was provided complete in this post), a discussion of the cover, and the Closing. Take a run through the Table of Contents. It is a very-detailed and well-illustrated book—using data from the real world, not models of a virtual world.
Who Turned on the Heat? is only available in pdf format…and will only be available in that format. Click here to purchase a copy. Thanks. Unless I can find funding for my research, it will be book sales and tips/donations that allow me to return to blogging full-time.
NOTE: With my new job, I may be a little slow responding to questions. Sorry.
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Brian Kahn also covered Cai et al. (2013) in his ClimateCentral post Climate Change Could Double Likelihood of Super El Ninos. (Thanks again Andrew for the link to the post at HockeySchtick.) Brian Kahn’s article included the following and a remarkable quote from Kevin Trenberth:
The core of Cai’s results, that more super El Ninos are likely, was disputed by Kevin Trenberth, a senior scientist at the National Corporation [sic] for Atmospheric Research.
He said some of the models used in the study overestimate the past number of El Nino events by a wide margin and do a poor job of representing them and their impacts.
“This seriously undermines the confidence that the models do an adequate job in ENSO (El Nino-Southern Oscillation) simulations and so why should we trust their future projections?” he said in an email.
Trenberth also said that some long-range climate models also fail to adequately simulate other natural climate patterns that influence El Nino let alone how they might also shift in a warming world.
I’m beginning to enjoy Kevin Trenberth again. (sarc on) I’m sure he’ll be pleased. (sarc off)
OOPS, forgot to thank Andrew and nevket240. Thank you!