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.
While I agree with Joe, that those of us actually looking, are well aware of this relationship and the connection with the PDO, Dr. Spencer’s paper quantifies a mechanism and provides some unique scientifically based insight to explain what we all know.
I disagree with comments that think this is giving some ground to alarmists. This is science, not politics. In politics you push propaganda, exaggerate and try to win a one sided battle, often distorting and manipulating. Whatever gets the job done.
In science, you interpret empirical data and try not to care where it leads you, even if it doesn’t match up perfectly with whatever your position is. It should never be contaminated with the idea of presenting it in a manner designed to match the extreme nature of an opposing view.
But it seems to me that S&B assume that the head not accounted for by ENSO is coming from CO2. Where is the proof for that? Or, should I have read the paper before commenting 🙂
A case in point about Nada a Nado. If neutral conditions are such a weak contender, say some, of climate and weather pattern variations, strong solar conditions should overtake such a weak sister. So here is your challenge solar enthusiasts. Try to prove your theory wrong like a good scientist should. Study the correlation between neutral ENSO trends, solar conditions and temperature. Lag it or not I don’t care. Your hypothesis should be that solar conditions should be the stronger and evident driver of climate and weather pattern variation under weak neutral oceanic conditions more so that at any other time. Comments?
JohnWho says:
November 11, 2013 at 10:49 am
For purposes of CACA debate, “climate sensitivity”, whatever its value may be, applies only to the doubling from 280 to 560 ppm. As so often noted here, the response in global temperature to CO2 concentration is logarithmic, so that most of the warming occurs in the first 100 ppm or less. As MIT climate scientist Dr. Lindzen says, adding more molecules is like painting a wall white, which doesn’t get much whiter with each new coat. Most of the effect occurs in the first one or two coats. So the next doubling to 1120 ppm would have negligible effect.
Pamela Gray says:
November 11, 2013 at 10:46 am
“You dismiss neutral (as others have so don’t feel too bad) as if nothing is going on that neutral conditions have an affect on”
Huh ?
I fully accept neutral ENSO as an intermediate state between El Nino and La Nina.
The only point I made was that during the current period of neutral ENSO the recharge rate is weaker than it would have been during the period of reduced cloudiness of the late 20th century.
And I don’t ‘believe’. I observe.
“The results also suggest the world will warm by 1.3 C (about 2.34° F) from a doubling of atmospheric CO2,… .”
So, Dr. Spencer does NOT believe that CO2 rise lags temperature rise. Great. (not)
While there is some useful repetition of the knowledge about ENSO as a climate driver, the main effect of this article is to support AGW. This article does far more damage to the cause of truth than it does good. The positive testimony for AGW from a “hostile witness” (Dr. Spencer has purportedly been on the side of the skeptics of AGW) gives the article’s support a weight a friendly witness’s testimony could never have.
It would have been better to have said nothing at all.
What a disappointment.
I feel like Washington must have felt when they told him about Benedict Arnold.
Roy Spencer says:
November 11, 2013 at 10:10 am
This goes far beyond just handwaving that “stronger El Ninos cause warming”.
That may be so, but it is unlikely to be anywhere near whole story. One or two commentators mentioned AMO factor, certainly for the N. Atlantic basin the AMO is the predominant and decisive factor.
N. A Subpolar gyre (SPG) is a major N. A. circulatory system where the cold Arctic currents overflow are mixed with the warm Gulf Stream’s waters. The SPG’s circulation is the engine of the heat transport across the North Atlantic Ocean, it is capable of influencing of the entire ocean circulation system Its major and highly variable component is the North Icelandic Jet current.
WHOI: “The North Icelandic Jet is a deep-reaching current that flows along the continental slope of Iceland. North Icelandic Jet (NIJ), contributes to a key component of the Atlantic Meridional Overturning Circulation (AMOC), also known as the “great ocean conveyor belt,” which is critically important for regulating Earth’s climate. As part of the planet’s reciprocal relationship between ocean circulation and climate, this conveyor belt transports warm surface water to high latitudes where the water warms the air, then cools, sinks, and returns towards the equator as a deep flow.”
Continental slope of the North Iceland is tectonically vary active; however this is not an easy variable to reconstruct, but the surface magnetic records are a reasonable even if not very accurate proxy.
The circulatory period of the SPG is variable, mainly in range 20+ years.
Calculated 20 and 30 years delta for magnetic field change along the continental slope of North Iceland (NIJ current’s path) and the Leohle’s temperature anomaly reconstruction are shown here:
http://www.vukcevic.talktalk.net/CT.htm
Of course correlation may be a coincidence (correlation is not necessarily causation), but if not, to dismiss wise may not be, even if the direct operating mechanism is not readily recognised.
Pamela Gray said:
“Your hypothesis should be that solar conditions should be the stronger and evident driver of climate and weather pattern variation under weak neutral oceanic conditions more so that at any other time. Comments?”
No.
Solar conditions affecting cloudiness will always be the driver.
Weak neutral oceanic conditions are just an intermediate state between El Nino (discharge) and La Nina (recharge).
In the end what matters is the balance between solar energy in and energy released by the oceans.
La Nada just means not much being released as compared to El Nino and not much being stored as against La Nina.
Stephen, you still need to consider your theory in light of correlations (if any indeed exist) between ENSO neutral, solar parameters, and temperature. Do the jets sit around and be idle in your hypothesis? What do they actually do under ENSO neutral? If your solar parameters are strong enough to push the jets this way and that, you should study jet positions, weather patterns such as blocking highs, and temperatures under ENSO neutral and see what your solar parameters are under those conditions. Have you? Or did you just concentrate on ENSO extreme events?
Stephen, in other words, work backwards from all ENSO conditions, not just extreme ones. By the way, I know about energy release and energy penetration under ENSO conditions. I also have read your theory about solar parameters pushing/pulling jets due to stratospheric/tropospheric expansion/contraction conditions set up by solar parameters (a very tenuous proposition at best). Your solar theory of pushing/pulling jets should hold under all ENSO conditions, including neutral. So what is the correlation working backwards when ENSO is neutral? There is lots of data. Tons of it. Work backwards from ENSO data. What does it say when ENSO is neutral about your solar theory? Come on. Spill it. What have been the solar parameters when ENSO has been in neutral territory (IE between -.5 and +.5)?
Is Dr. Roy is explicitly calling clouds a forcing?
Pamela Gray says:
November 11, 2013 at 10:46 am
El nado means the swim.
In order to NOT break faith (as so eloquently expressed in “Flanders’ Fields,” posted today by Allan MacRae on the heart attack thread) with our veterans and those who made the ultimate sacrifice, I post this, today, on Veteran’s Day……. to THANK YOU.
To our great U. S. Armed Forces (and our Allies), veterans and active duty,
you can win ANY war –
when the politicians, the media, and the public don’t betray you.
In remembrance…
Thank you, “Dad.” Thank you, “Mom.”
“’Greater love hath no person than this,
that one lay down one’s life for one’s friends.”
John 15:13.
LAND OF THE FREE, BECAUSE OF THE BRAVE.
.
.
.
Gratefully yours,
Janice
P.S. @ur momisugly All Enemies of Freedom: Listen up. America lives.
Those who love Liberty far outnumber those who serve tyranny.
Our veterans’ sacrifice of time, of health,
of friends, of family…. WAS NOT IN VAIN.
We will outlast the socialists.
America is.
1.3C is near enough the equilibrium climate sensitivity so as many suspected, the feed backs are largely self regulating.
Well, my first call for civility has gone unheeded. I will try again.
Yes, Joe and Pam, you are right. We all knew this to be true. It is no great revelation to climate realists. But, as Roy points out, they have quantified the effect and described the mechanism in more detail than has ever been done before. That’s important. That is how the game is played. IT must be published and spelled out in detail for it to be considered as a contender to the current paradigm. ‘Truth’ is a function of publishing; and while that pisses me off no end, I can no longer rationally deny it.
And Jimbo, there is no real social/political debate if climate sensitivity to increasing CO2 is half what the IPCC has been peddling. There is no crisis. There is no need for regulation or taxes or other forms of control. Alarmists may still try and pedal an ‘acidic ocean’ scam, but that is not going to resonate much with the people and the politicians, nor hold up to additional research. Look, they fired their best, scary shots and have still struggled to get traction, even when most people believed them. Cutting the threat in half takes all the wind from their sails. You may be right and sensitivity may be even less than half the IPCC estimates, but this paper is much closer to the truth and deserves to be heralded as such.
We are a skeptical and contentious bunch, but we are all united in wishing to see the current climate change paradigm dismantled and replaced with one that is much more scientifically accurate. Such paradigm changes may happen quickly, but only after the methodical build up of evidence against the old and for the new. This paper is an important step in that methodical build up. The new paradigm does not have to be perfect. In fact, it can’t be perfect, but it can be a whole lot better than the one we have now.
Do we really want to trash the developing new paradigm because it may not be perfect in our eyes? Isn’t it better to take a “Yes! And…” approach, than a “Well but…” or “Who cares?” approach?
I, for one, greatly appreciate Spencer and Braswell’s heavy lifting on this.
Clouds reflect solar irradiance back to space. Clear skies let it in and at depth in the oceans. So as a gatekeeper to oceanic warming below the surface that is later discharged under calmer wind conditions in various locations on the globe, clouds do indeed form part of the driving force behind land temperatures. What drives the clouds? The chicken or the egg? Could this be a leaky closed loop system (each cog being a driver of the next with energy leaking out to space here and there) that is kept at a variable pace with solar energy being let back in at various amounts to top off the tank so to speak?
Roy, I was being tongue in cheek. I hope you don’t mind. I truly do admire your work and glad you are on our side. Very glad. Besides, I can’t even get my dog to listen to me.
Ulric, that’s the point of the study….to examine the cumulative effects of ENSO during the ~30 yr periods when either El Nino or La Nina are stronger.
Ok so you got half the picture. Now add in the CUMULATIVE (ie. integrate under the curve) total solar irradiance, and CUMULATIVE solar magnetic events (to trigger cloud formation) and low and behold you’ve reduced the ‘apparent’ “forcing” of CO2 to a big fat zero. Instead you’ve proven that CO2 is being ‘driven’ by temperature not ‘driving’! (Thank you prof. Salby)
OK NOW you’ve got the picture right!
Thank you for this work, small wins are a blessing too. Lets limp towards admitting the obvious truth. Dr. Spencer, was the pending publication of this article why you were so unnecessarily hard on Willis theory recently? Willis proposed that CLOUDS had a direct SHORT term temperature balancing affect. You are admitting that CLOUDS have a long term heat reflecting temperature balancing affect. Not exactly the same (one requires no math on the temperture record, the other requires averaging temp. differences yr-to-yr which reduces their meaning to exactly . . . . NOTHING!) but the end result is that WATER not CO2 is the big GHG that controls the thermostasis in our climate system. And as long as there is LOTS and LOTS of water on the earth, it can NEVER overheat or undercool! (is that even a word?)
Why spend ANY time at all looking at long term trends of a few tenths of a degree, when it is obvious that the climate systems is self-regulating, (as long as that big ball in the sky behaves). C’mon, the SUN is at the center of our solar system and is the source of our heat – NOT CO2 – and WATER is the reason our little ball is BLUE – CO2 only absorbs/reflects in the infrared and even at that only a fraction as effectively as WATER does.
In order to participate in “Green House Gas ‘Warming’ “, CO2 has to absorb IR light energy. In order to absorb it has to have an extinction coefficient at the wavelengths of interest. In addition, IT MUST BE PRESENT AT A CONCENTRATION THAT IS HIGH ENOUGH TO DISTINGUISH IT FROM OTHER ABSORBING MOLECULES. (Yes there is a concentration term in Beers Law) Not only does CO2 have a fraction of the extinction coefficient as water does in the infrared, but it’s ridiculously miniscule concentration when compared to water renders it’s contribution to the GHG effect virtually meaningless! (ESPECIALLY IN HIGH HUMIDITY REGIONS – LIKE CLOUDS!)
IF CO2 had the “forcing” you concede that it has, THEN wouldn’t we see the seasonal variability that is measured presently in the average annual seasonal variability across the globe? Wouldn’t we see a direct long term drift that parallels the long term upward drift of CO2’s concentration? Wouldn’t we see continued upward movement on the masticated mashed up, “adjusted”, ‘temperature anamoly” “data” instead of a long term 17 yr. hiatus to any temp change at all? Please explain again why CO2 concentration is still rising, but with NO downward pressing signigicant PDO events to speak of over the long term, surface temperature has “on average” remained unchanged? but instead has spiked up and down in any given year or season, with no rhyme nor reason that can easily be seen correlating to spikes or dips in CO2?
I see the correlation in your paper of temp being influenced by clouds and a large portion of the “forcing” being attributed to “natural variability”. I fail to see the evidence to support your continued attribution of the remaining “unexplained forcing” to CO2.
Respectfully,
Don V
Phlliiifffffftsplaatttttspraaayyyy! Cough hack gag!!!!! El Nado! The Swim! Hilarious!
I don’t what this is all about: the change in ocean temperature down to about 2000M is at most 0.1 degree C for the period in question. If Spencer believes one can measure this with any accuracy, then I have bridge in Brooklyn to sell him.
…and we don’t claim this study gets “the answer”. As others have suggested, it might well be there are other climate forcings we have not included. We just examined how inclduing ENSO as a pseudo-forcing reduces estimated future warming by 50%.
Gee, if only ENSO can do that, what about the AMO, or indirect solar effects, or ??? ENSO just happened to be the most obvious signal in the globally averaged ocean temperature data at various depths, so we started with it.
Bruce, you really need to read my blog post, where I state that *assuming* the ocean temperatures can be believed, then…
DonV says:
November 11, 2013 at 11:42 am
Earth’s climate is homeostatic, or at least has been for the past 543 million years, but it has apparently experienced runaway global cooling in the more distant past, when the sun was about six (Marinoan) to 22% (Huronian) weaker than now. The long-lasting Huronian global glaciation (2400 to 2100 Ma) may have been triggered by the oxygen catastrophe. But long-term even these extreme Snowball or Slushball Earth incidents were regulated & balmier times resumed.
Pamela Gray says:
November 11, 2013 at 11:43 am
Hope that wasn’t your coffee being launched keyboardward.