Warming since 1950s partly caused by El Niño
HUNTSVILLE, Ala. (Nov. 11, 2013) – A natural shift to stronger warm El Niño events in the Pacific Ocean might be responsible for a substantial portion of the global warming recorded during the past 50 years, according to new research at The University of Alabama in Huntsville (UAH).
“Our modeling shows that natural climate cycles explain at least part of the ocean warming we’ve seen since the 1950s,” said Dr. Roy Spencer, a principal research scientist in UAH’s Earth System Science Center and the new study’s lead author. “But we also found that because the globe has had more frequent La Niña cooling events in the past ten or fifteen years, they are canceling out some of the effects of global warming.”
The paper detailing this research, “The Role of ENSO in Global Ocean Temperature Changes During 1955-2011 Simulated with a 1D Climate Model,” is scheduled for publication in the Asia-Pacific Journal of Atmospheric Science, and is available online at:
http://link.springer.com/article/10.1007/s13143-014-0011-z.
The results also suggest the world will warm by 1.3 C (about 2.34° F) from a doubling of atmospheric CO2, which is only one-half of the warming expected by most climate researchers.
General circulation climate models — such as those used to forecast global climate change — do not reproduce the tendency toward 30 year periods of stronger El Niño or La Niña activity, as are seen in nature.
Spencer and co-author Dr. Danny Braswell used all of the usual climate modeling forcings — including carbon dioxide and other greenhouse gas enrichment — in their study, but also plugged the observed history of El Niño ocean warming and La Niña ocean cooling events into their model to calculate the 61-year change in global ocean temperature averages from the sea surface to a depth of 2,000 meters.
“We used the observed ENSO (El Niño Southern Oscillation) history since the 1950s as a pseudo forcing factor of the model,” Spencer said.
When they ran their ocean model without ENSO, they arrived at the same general conclusions as the more complex general circulation climate models. When they added data from past El Niño and La Niña events as only a change in ocean mixing, the model indicated a climate system that is slightly less sensitive to CO2-induced warming than has been believed.
But the biggest change was when the model was allowed to change cloud cover with El Niño and La Niña in the same way as has been observed from satellites. The results suggest that these natural climate cycles change the total amount of energy received from the sun, providing a natural warming and cooling mechanism of the surface and deep ocean on multi-decadal time scales.
“As a result, because as much as 50% of the warming since the 1970s could be attributed to stronger El Niño activity, it suggests that the climate system is only about half as sensitive to increasing CO2 as previously believed”, Spencer said.
“Basically, previously it was believed that if we doubled the CO2 in the atmosphere, sea surface temperatures would warm about 2.5 C,” Spencer said. That’s 4.5° F. “But when we factor in the ENSO warming, we see only a 1.3 C (about 2.3° F) final total warming after the climate system has adjusted to having twice as much CO2.”
It was previously known that Pacific Ocean warming and cooling events come and go in roughly 30-year periods of predominance, where El Niño warming events are stronger than La Niño cooling events for approximately 30 years, followed by roughly three decades where the reverse is true.
During the period of this study, cooling events were dominant from the 1950s into the late 1970s. That was followed by a period of strong El Niño warming activity that lasted into the early 2000s. The current phase has seen increased La Niña cooling activity.
Spencer said it is reasonable to suspect that the increased La Niña cooling might be largely responsible for an ongoing “pause” in global warming that has lasted more than a decade. If that is the case, weak warming might be expected to revive when this phase of the El Niño-La Niña cycle shifts back to a warmer El Niño period.
The study was the result of a debate over whether clouds can be part of an active forcing mechanism for global warming, or are just a passive response to temperature change.
“What we found is, to explain the satellite data we had to invoke a change in clouds nine months before the peak of either an El Niño or a La Niña,” Spencer said. “When the clouds change, it takes time for that to translate into a temperature change.
“We get the best fit to the observations when we let clouds cause some of the temperature change. These cloud changes are occurring before the temperature starts to respond, so they can’t be caused by the temperature changes.”
Before an El Niño Pacific Ocean warming event, global cloud cover decreases, allowing more solar energy to reach the Earth’s surface and be converted into heat. On the flip side, before a La Niña Pacific Ocean cooling event, cloud cover increases, shading more of the Earth’s surface and reflecting an increased amount of solar energy back into space.
While changes in cloud cover intensify the warming or cooling of these ocean events,
Spencer and Braswell still found that two-thirds of the sea surface temperature changes during both El Niño and La Niña events are driven by changes in ocean mixing. But the one-third forcing by clouds turns out to be an important component, substantially changing our interpretation of how sensitive the climate system is to CO2 emissions.
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The role of ENSO in global ocean temperature changes during 1955–2011 simulated with a 1D climate model
Abstract
Global average ocean temperature variations to 2,000 m depth during 1955–2011 are simulated with a 40 layer 1D forcing-feedback-mixing model for three forcing cases. The first case uses standard anthropogenic and volcanic external radiative forcings. The second adds non-radiative internal forcing (ocean mixing changes initiated in the top 200 m) proportional to the Multivariate ENSO Index (MEI) to represent an internal mode of natural variability. The third case further adds ENSO-related radiative forcing proportional to MEI as a possible natural cloud forcing mechanism associated with atmospheric circulation changes. The model adjustable parameters are net radiative feedback, effective diffusivities, and internal radiative (e.g., cloud) and non-radiative (ocean mixing) forcing coefficients at adjustable time lags. Model output is compared to Levitus ocean temperature changes in 50 m layers during 1955–2011 to 700 m depth, and to lag regression coefficients between satellite radiative flux variations and sea surface temperature between 2000 and 2010. A net feedback parameter of 1.7Wm−2 K−1 with only anthropogenic and volcanic forcings increases to 2.8Wm−2 K−1 when all ENSO forcings (which are one-third radiative) are included, along with better agreement between model and observations. The results suggest ENSO can influence multi-decadal temperature trends, and that internal radiative forcing of the climate system affects the diagnosis of feedbacks. Also, the relatively small differences in model ocean warming associated with the three cases suggests that the observed levels of ocean warming since the 1950s is not a very strong constraint on our estimates of climate sensitivity.
What Roy Spencer has done is clearly a step forward from the IPCC model versions. But it’s still only a model, and the mechanisms behind ENSO are not known, so we should be very cautious with this paper.
On the plus side, the paper does explain a lot of the model’s logic, so we are able to make some sort of reasonable judgement of its findings.
On the negative side, there are a number of potentially important factors which are not mentioned, and which could invalidate the findings. One would be the hydrological cycle (evaporation, precipitation, etc) which is under-represented in climate models and presumably also in Roy’s. Roy appears to have added only clouds, not the full hydrological cycle. Another would be the major ocean cycles – AMO, PDO, etc – and no doubt there are other important omitted factors.
My feeling is that the major finding of the paper – a much smaller ECS – is too unreliable, and that we should continue with the null hypotheses that (a) we don’t know what the value of ECS is, and (b) we don’t even know if there is an ECS.
Steven Mosher says:
November 11, 2013 at 12:51 pm
2. CS for C02 cannot be zero or close to zero
>>>>>
Glad you left out “negative”….
DonV says:
November 11, 2013 at 12:43 pm
I agree and in one of my essays I deal with it.
The phase changes of water do indeed provide a more effective method of shifting energy than the adiabatic uplift and descent cycle that operates in the background.
The net effect of those phase changes is to enable system equilibrium to be maintained with less work needing to be done by the adiabatic cycle. In other words the necessary circulation changes can be less violent.
It is still the gas constant for our specific atmospheric mix of gases that controls it all though because it specifies the amount of kinetic energy needed at the surface to both hold up the weight of atmospheric mass AND achieve top of atmosphere radiative balance.
That kinetic energy also determines the size and speed of the water cycle so we come full circle.
Steven Mosher says:
November 11, 2013 at 12:44 pm
How did you derive ECS ~= 2*TCR?
Even IPeCaC shows, at least in this example, ECS ~= 1.75*TCR:
http://www.ipcc.ch/ipccreports/tar/wg1/fig9-1.htm
Steven Mosher says:
November 11, 2013 at 12:51 pm
Sure CS for a doubling of CO2 can be close to zero, if not for doubling from 280 to 560, then for from, say, 1200 to 2400, at which level any theoretical increase would be practically immeasurable.
@Mike Maguire –
Attempting to find middle ground between a position that is patently false (significant CO2 forcing in climate change) and one that is obviously correct (CO2 forcing indistinguishable from zero) is what is political. Sticking to our guns concerning the fallacy of AGW is not political – it’s simply honest.
I am reminded of how astronomer Tycho Brahe tried to compromise between an Earth-centric and a Sun-centric (i.e., Copernican) solar system by claiming that the Sun revolved around the Earth and the other planets orbited the Sun. Such compromises only produce garbage theories. Facts don’t bend, and you can’t be “half pregnant.”
To see a negative CO2 sensitivity over thousands of years see Fig 4 at
http://climatesense-norpag.blogspot.com
Stephen, you do not have a falsifiable entry point into your theory. If the correlations between solar indices and jet indices do not match, as you say is the case now and then, you retreat to the bottom up half of your theory, citing natural intrinsic variation as the source of climate/weather pattern variation trends. Okay so let’s talk about the half and half nature of your theory. So tell me, just how strong do the solar indices have to get before they can overtake intrinsic sources of temperature trends? Or if you want, how weak do the intrinsic sources of temperature trends have to get before solar indices take over? And do the two halves (top down and bottom up) of your drivers of temperature trend take on a double whammy when in sync? What does the data say about that?
Re my previous post above – would summarize by saying there’s no compromise possible between a lie and the truth – all you get is, at best, is a half-truth.
Mike Jonas says:
November 11, 2013 at 12:59 pm
But it’s still only a model, and the mechanisms behind ENSO are not known, so we should be very cautious with this paper.
It is worth noting that there is a correlation between the ENSO and the sub equatorial Pacific
http://www.vukcevic.talktalk.net/ENSO.htm
It is worth noting that there is a correlation between the ENSO and the sub equatorial Pacific tectonics
http://www.vukcevic.talktalk.net/ENSO.htm
I hate to ask a dumb question but I’m just starting to wade into the carbon dioxide emissions and global warming data. Just quickly looking at the absorption spectrum of carbon dioxide, it looks like it’s absorbing mostly longer wavelength (low energy) IR and in a relatively narrow band. As the concentration of CO2 increases you will get diminishing returns as you run out of photons to absorb in that radiation band. In addition, the pathlength of the atmosphere is pretty long so it can probably absorb most of the radiation at a pretty low concentration. It seems mathematically after a certain threshold concentration of CO2 is attained it’s contribution to additional warming should approach zero. How do the current models deal with this physical limitation?
“What Roy Spencer has done is clearly a step forward from the IPCC model versions. But it’s still only a model, and the mechanisms behind ENSO are not known, so we should be very cautious with this paper.”
And anything Dr. Roy says, in fact.
Just to compare the rock solid logic straightfroward of McIntyre the non professional, to Dr. Roy’s evasiveness, gives a clue.
Guys…..when negotiating, you don’t go all out to totally destroy your opponent. When its obvious that your adversary is flailing around, obviously lost, you offer him an open door to escape through with some form of self respect intact. This paper allows alarmists to mumble that they may have inadvertently overstated CO2 sensitivity, sorry, but we meant well. Hence it got published. Of course you did old chap, now, shuffle off through that open door, don’t call us, we will call you. Once they all mumble this, the next published paper goes further, dropping sensitivity even further. Baby steps folks, baby steps.
John, you ask “How do the current models deal with this physical limitation?”
I cannot answer the question, but one thing I can guarantee for you. If you ask the question on Judith Curry’s Climate Etc, you will get all sorts of answers. none of which I believe are true. Judith usually has an open thread each weekend. Why don’t you come over and try at the end of this week?
Roy Spencer’s blog post that discusses this paper is worth a read:
http://www.drroyspencer.com/2013/11/our-new-paper-el-nino-warming-reduces-climate-sensitivity-to-1-3-deg-c/
John: “As the concentration of CO2 increases you will get diminishing returns as you run out of photons to absorb in that radiation band.”
Not my bailiwick, but I’m told that the continued (albeit diminishing) reduction in long-wave-infrared escape occurs in the skirts of the rejection bands, where a great deal of concentration is required to result in a small amount of absorption. I.e., it’s true that there are bands at which the first kilometer of atmosphere is already essentially opaque, but there are adjacent bands where the probability of a photon’s traversing the entire atmosphere unmolested remains significant and sensitive to further CO2 concentration.
Steven \Mosher you write “2. CS for C02 cannot be zero or close to zero.”
I agree it cannot be zero, but I fail to understand why it cannot be close to zero, when it is impractical to measure it. All we have are guesses as to what it’s value is.
Mosher – it can be zero, if increased co2 increases the biosphere on both land, Ocean and in the air (spores/pollen, etc), which again changes albedo enough to offset the blackbody response of co2.
Not enoug Research here, i feel.
Roy
I appreciate that you have looked into this but I have to say as a trained physicist and a working engineer, I’m actually embarassed by physicists when it comes to Co2 forcing and this dubious concept of Climate Sensitivity.
Simply put the supposed effect is due to a given power density of 4W/m2 for Co2 doubling heating a surface (in fact, 4W/m2 is directly for water – 70% of the effect according to Jim Hansen)
So why do we not see characterisation curves for IR heating at 15 microns? Where are all the experiments starting for high power densities down to lower ones showing the heating of water. Where are the curves showing the relationship and the losses, the real effect? HIgher power densities have been tested on milk for making bacteria inactive but no holistic approach appears to have been taken to produce (as far as possible) a forcing curve. A REAL forcing curve, not the idealistic logarithmic emission curve with no corrections for real surfaces in an atmosphere.
Only when this is done do we start to link the concept of sensitivity to the climate because you have the data and the curves.You don’t work from the system downward. There are too many competing variables.
This is basic science. Start by looking at the parts then build it up.
If we as sceptics, keep trying to model the climate and do all this other XBox type stuff then we are just as bad as the theoreticians who have a grip on the current thinking and policy.
People need to start doing some experiments.
Joseph Bastardi says: @ur momisugly November 11, 2013 at 9:49 am
….How is this some brilliant finding.
Its amazing watching knowns, things observed years ago being funded and now somehow coming to light as a brilliant discovery. This is a known among nuts and bolts forecasters that have worked in this field for years.
Simply amazing
>>>>>>>>>>>>>>>>
Joe, we here at WUWT have been aware of this for years. And as you said it has been known among nuts and bolts forecasters for many years. Now we have a
Palan actual peer-reviewed paper to stuff in the Warmist’s faces complete with data.That it managed to get through peer-review is what is amazing. :>)
Darn it I did the strike off and it did not work…
@Gail (re: 2:05pm)… thus proving that such things (whatever the glitch, here) can happen even to the best of us.
To bring ENSO in as a cause of warming is nonsense. That multivariate ENSO index they use is a mishmash of empirically chosen variables that follow but do not predict ENSO activity. If you must track ENSO use Nino 3.4 that has a physical meaning. Secondly, ENSO is cyclical and there are equal numbers of both El Nino phases and La Nina phases. The apparent balance may shift if the equatorial counter-current for some reason is blocked,causing an El Nino modoki in mid-ocean, but the rule that there is one La Nina for each El Nino does not change. And then they just babble on about ENSO-related radiative forcing proportional to MEI. That is abject nonsense and should have been sufficient reason for rejecting the paper. In the mix they also use anthropogenic and volcanic forcings, both non-existent phenomena. For an explanation of why there is no volcanic forcing read my book. Anthropogenic forcing does not exist because there is no such thing as greenhouse warming. Its absence is easy to confirm.Today there is more carbon dioxide in the air than ever before but there is no warming whatsoever. This has been going on for 15 years and will continue. There was a similar no-warming period of 18 years in the eighties and nineties that official temperature curves covered up with a phony “late twentieth century warming.” But GISTEMP, HadCRUT, and NCDC have decided to stop showing that fake warming and aligned their data for that period with satellites. This was done secretly last fall and no explanation was offered. To get the total of no-warming years add this to the current 15 years and you find that there has been no greenhouse warming for the last 33 years. Can anyone believe that greenhouse warming might still have existed more than 33 years ago? Not I. I am just sorry that these guys are so uninformed about climate science despite supposedly being practitioners of this esoteric craft. Not to mention editors who allowed this nonsense go through.
mickyhcorbett75 you write “People need to start doing some experiments.:
I agree, EXCEPT, it is impossible to do controlled experiments on the earth’s atmosphere. The correct conclusion to come to is that science, physics, cannot tell us what happens when you add more CO2 to the atmosphere from current levels. If the IPCC had been run by people like you and me all those years ago, that is what the conclusion would have been, and all this nonsense would never have happened.
Jim
I agree that on the Earth’s scale it gets difficult. BUT the proposed forcing effect can be tested. It is simply IR heating of a surface in contact with an atmosphere. I mean I worked in the space industry for almost a decade and you can buy and use solar simulator lamps, that are able to shine a UV-visible spectrum on a spacecraft in a vacuum chamber, in order to test the solar panels and any heating effects. So IR shouldn’t be hard
Plus like I said scientists in the food industry uses ~1Kw/m2 to heat up milk to kill bacteria so it isn’t like heating water in a controlled way is hard either.
The problem is that people are thinking too big whilst missing the real details.