From ETH Zurich –Why global warming is taking a break
The average temperature on Earth has barely risen over the past 16 years. ETH researchers have now found out why. And they believe that global warming is likely to continue again soon.
Global warming is currently taking a break: whereas global temperatures rose drastically into the late 1990s, the global average temperature has risen only slightly since 1998 – surprising, considering scientific climate models predicted considerable warming due to rising greenhouse gas emissions.
Climate sceptics used this apparent contradiction to question climate change per se – or at least the harm potential caused by greenhouse gases – as well as the validity of the climate models. Meanwhile, the majority of climate researchers continued to emphasise that the short-term ‘warming hiatus’ could largely be explained on the basis of current scientific understanding and did not contradict longer term warming.
Researchers have been looking into the possible causes of the warming hiatus over the past few years. For the first time, Reto Knutti, Professor of Climate Physics at ETH Zurich, has systematically examined all current hypotheses together with a colleague. In a study published in the latest issue of the journal Nature Geoscience, the researchers conclude that two important factors are equally responsible for the hiatus.
El Niño warmed the Earth
One of the important reasons is natural climate fluctuations, of which the weather phenomena El Niño and La Niña in the Pacific are the most important and well known. “1998 was a strong El Niño year, which is why it was so warm that year,” says Knutti. In contrast, the counter-phenomenon La Niña has made the past few years cooler than they would otherwise have been.
Although climate models generally take such fluctuations into account, it is impossible to predict the year in which these phenomena will emerge, says the climate physicist. To clarify, he uses the stock market as an analogy: “When pension funds invest the pension capital in shares, they expect to generate a profit in the long term.” At the same time, they are aware that their investments are exposed to price fluctuations and that performance can also be negative in the short term. However, what finance specialists and climate scientists and their models are not able to predict is when exactly a short-term economic downturn or a La Niña year will occur.
Longer solar cycles
According to the study, the second important reason for the warming hiatus is that solar irradiance has been weaker than predicted in the past few years. This is because the identified fluctuations in the intensity of solar irradiance are unusual at present: whereas the so-called sunspot cycles each lasted eleven years in the past, for unknown reasons the last period of weak solar irradiance lasted 13 years. Furthermore, several volcanic eruptions, such as Eyjafjallajökull in Iceland in 2010, have increased the concentration of floating particles (aerosol) in the atmosphere, which has further weakened the solar irradiance arriving at the Earth’s surface.
The scientists drew their conclusions from corrective calculations of climate models. In all climate simulations, they looked for periods in which the El Niño/La Niña patterns corresponded to the measured data from the years 1997 to 2012. With a combination of over 20 periods found, they were able to arrive at a realistic estimate of the influence of El Niño and La Niña. They also retroactively applied in the model calculations the actual measured values for solar activity and aerosol concentration in the Earth’s atmosphere. Model calculations corrected in this way match the measured temperature data much more closely.
Incomplete measured data
The discrepancy between the climate models and measured data over the past 16 years cannot solely be attributed to the fact that these models predict too much warming, says Knutti. The interpretation of the official measured data should also be critically scrutinised. According to Knutti, measured data is likely to be too low, since the global average temperature is only estimated using values obtained from weather stations on the ground, and these do not exist everywhere on Earth. From satellite data, for example, scientists know that the Arctic region in particular has become warmer over the past years, but because there are no weather stations in that area, there are measurements that show strong upward fluctuations. As a result, the specified average temperature is too low.
Last year, British and Canadian researchers proposed an alternative temperature curve with higher values, in which they incorporated estimated temperatures from satellite data for regions with no weather stations. If the model data is corrected downwards, as suggested by the ETH researchers, and the measurement data is corrected upwards, as suggested by the British and Canadian researchers, then the model and actual observations are very similar.
Warming to recommence
Despite the warming hiatus, Knutti is convinced there is no reason to doubt either the existing calculations for the climate activity of greenhouse gases or the latest climate models. “Short-term climate fluctuations can easily be explained. They do not alter the fact that the climate will become considerably warmer in the long term as a result of greenhouse gas emissions,” says Knutti. He believes that global warming will recommence as soon as solar activity, aerosol concentrations in the atmosphere and weather phenomena such as El Niño naturally start returning to the values of previous decades.
Literature reference
Huber M, Knutti R: Natural variability, radiative forcing and climate response in the recent hiatus reconciled. Nature Geoscience, online publication 17 August 2014, doi: 10.1038/ngeo2228
Even the use of the term “warming hiatus” shows their un-scientific bias. All we can say is that warming has now stopped. Weither it starts up again, or ever starts up again, is the whole point. Saying it is only on “hiatus” is assuming the conclusion you are trying to prove. Go back to High School science and start over, please.
The discrepancy between the climate models and measured data over the past 16 years cannot solely be attributed to the fact that these models predict too much warming, …i>
It is not because the models are wrong, it is because the data is wrong.
You are correct, John W. Garret: you can’t make this stuff up.
/grin
Of course, the same error that they are asserting is occurring in the Arctic could have also occurred in the Antarctic in the past record, so that the net effect of the correction could be null. Or, we could just look at lower troposphere temperatures, which are not subject to the measurement and sparsity errors of the surface record, and note that they’ve been all but flat over almost all of the 30+ years they have been measured, and use them the way Lief et. al. are using secondary e.g. magnetic data to correct the equally corrupted and unreliable sunspot record.
I don’t think even people like this undoubtedly honest scholar realize that the LTT record is a hard constraint on how much you can “adjust” the contemporary record, and that adjusting the past record, in addition to being enormously dangerous and susceptible to confirmation bias, can be done only at the expense of increasing the error bars to the point where the change really doesn’t matter. Almost by definition, in fact. There ain’t no such thing as a free statistical lunch, and you can’t squeeze a given collection of data with various uncertainties in it for more certainty than it contains, from an information theoretic point of view. You can only insert your own biases or beliefs into it on the basis of a belief that your model for doing so is right. That’s all well and good, but if you do that you cannot then turn around and use the data to prove that your model is right. Somewhere in there you need an independent way to affirm the model.
The one useful take home message from the top article is that yes, models can be built that are in much better agreement with observation, and yes, they can only get there by re-attributing the importance of discrete events such as ENSO oscillations and long term variabilities such as the sun so that the natural variation is a strictly larger fraction of the observed variation. As you make the 1997-1998 super-ENSO event responsible for more of the single burst of global warming visible over the last 75 years, which all occurred between roughly 1980 and 2000 (or arguably over the even shorter interval 1983-1998) then you leave less room for CO_2 to be a cause for the rest.
Nobody (rational) doubts that increasing CO_2 will have a net positive effect on the average temperature. The real question is: how large an effect can we expect? This, in turn, empirically depends in critical ways on the way natural variability and CO_2 driven variability are apportioned, which is in turn basically impossible to precisely determine as the two are not separable in the dynamics of any climate model; one is stuck making guesses that are nearly impossible to defend. An argument can be made for total feedback from the water cycle alone being strongly negative and cancelling nearly all of the CO_2-linked warming. An argument can be made (and often is:-) for it being the exact opposite, for water vapor to be a strong positive feedback, in spite of the general empirical divergence of models that are built on top of this assumption.
That’s one thing the top article apparently ignores right from the beginning. By attributing more of the lack of warming to increased volcanic aerosols, it maintains the fiction that the temperature rise we observe is certain to be a balancing of CO_2 warming, strong positive feedback from water vapor that much more than triples or quadruples that warming, and a variety of aerosols that cancel much of that warming to leave us with an overall doubling (plus some assumptions as to the strength of the original CO_2-only warming.
But what if they have the sign of the net water vapor feedback wrong from the beginning? What if ENSO and non-grand solar maximum were responsible for most of the warming observed in the entire 20th century, with direct CO_2 forcing being mostly cancelled by water vapor and atmospheric pressure and circulation feedbacks? This is not all that implausible, given that if one assumes that the Earth is generally in a state of approximate GHG balance when one isn’t adding CO_2, water vapor must be at the crossover point where increasing it leads to negative feedback or else the temperature would not be locally stable. This is a simple property of stable equilibrium — perturbing he system away from it must produce a net forcing back to equilibrium, not away from it.
That is what is so puzzling to me. They are asserting the following chain of reasoning:
a) The Earth is in a (dynamic) equilibrium within small responses to things like solar variability.
b) Water vapor is a powerful greenhouse gas — indeed the most important greenhouse gas responsible for over 90% of the total GHE warming relative to the Earth’s greybody temperature.
c) Increasing water vapor must increase global average temperature. Note that this assertion is contradicted by a) — if true, the global average temperature would increase as every increase in temperature increases water evaporation from the ocean, which then warms it still more. In simple fact, any increase in water vapor in the asserted equilibrium of a) from increased warming must lead to net cooling and an eventual restoration of the equilibrium water vapor concentration.
d) Increasing CO_2 must increase global average temperature.
e) This in turn must increase water vapor.
f) From c), we expect to get even more warming from increased CO_2 because of increased water vapor.
How, I ask, can they possibly defend assertion c) without destabilizing the entire climate to increases in water vapor, enabling runaway solutions even if there are no changes in anything else? The net feedback from increased water vapor in the neighborhood of any asserted equilibrium must change sign at the equilibrium point, just as is the case of the force exerted by a mass on a spring or the combined action of string and gravity on a pendulum!
They are performing the mathematical equivalent of asserting that if you pull a mass on a spring a small distance away from a stable equilibrium point with your finger, the spring will stretch even more because of some separable part of the net total force that pulls it back towards equilibrium. This seems rather implausible to me.
rgb
Quote:
“Climate sceptics used this apparent contradiction to question climate change per se – or at least the harm potential caused by greenhouse gases – as well as the validity of the climate models. Meanwhile, the majority of climate researchers continued to emphasise that the short-term ‘warming hiatus’ could largely be explained on the basis of current scientific understanding and did not contradict longer term warming.”
Quote:
“Although climate models generally take such fluctuations into account, it is impossible to predict the year in which these phenomena will emerge, says the climate physicist.”
**********
So, in their own words, these alarmist scientists are admitting that their models don’t do El Ninos and La Ninas, but they are still right.
And their models don’t do clouds, but they are still right.
And they can’t say for sure what the climate’s sensitivity level to the greenhouse gas effect of CO2 is, and they can only insert their best guesses into their models. But they are still right.
Yea, right. Blah, blah, blah, blah, blah……
It’s like what my Dad always used to jokingly say: “I’m not always right, but I’m never wrong.”
New! “Press Release Drinking Game” by D Aschim
-drink when you read “Climate Change” used as though climate doesn’t change.
-drink when any warming is prima facie bad (ex from extract: like the “drastic 90s warming” I didn’t notice as I lived through it!)
-drink when it is claimed natural events cool the earth but only man warms it!
-drink when you can falsify a bald assertion with observation (claim: the atmosphere is filled with particles from volcanoes etc even though the atmospheric apparent transmission hasn’t changed see http://www.esrl.noaa.gov/gmd/webdata/grad/mloapt/mlo_transmission.gif
-drink when logic and science principles are tossed out the door (claim:” If the model data is corrected downwards… and the measurement data is corrected upwards… then the model and actual observations are very similar.”)
Now we are on an even footing since it has become apparent to me that climate scientists are playing some sort of sciencey drinking game before they write this stuff! “My hypothesis is untestable- Drink!” “Observation contradicts my prediction- Drink!” “Jim is writing a paper saying the evidense falsifying my theory can be ignored- Two Drinks!”
note: please drink responsibly…
Is it not true that a predicted consequences of the greenhouse effect, specifically that of CO2 is as follows
1) feedback of water vapor at low altitudes, therefore higher humidity,
2) cooling at higher altitudes, especially over the oceans in the tropics, therefore a predicted cool zone.
3) The larger temperature gradient from the earth’s surface to higher altitudes would therefore cause more atmospheric movement and more extreme weather.
The items stated above should happen and be observed irrespective of climatic events mentioned in this article. Looking at short term and long term historical values, I do not see any of the above being observed.
Any comments?
dp has the comment of the day. The 98 El Nino released warmth that was already there prior to the onset of the El Nino. So the questions are, 1) where did that warmth come from? Yes it was in the oceans, but 2) how did it get in the oceans and from what source? And 3) did the tiny increase in anthropogenic CO2, even with water vapor amplification of downwelling longwave infrared, add to the larger source in a measurable way? And 4) how does it come out to warm the air?
Answers
1) Solar TSI absorbed by the top oceanic 700 meters.
2) When the skies are clearer, more of the solar spectrum gets into the oceans but clear skies also mean that sea surfaces may be roughed up by winds which mixes layers together making it look like nothing is heating up at all in the oceans.
3) Not even barely.
4) When the winds calm down (IE El Nino), the ocean layers become more defined with the warmest temperatures rising to the top where, because of the differences in temperatures between that top layer and the air above it, the surface begins to evaporate, sending that heated moist air into the atmosphere. Through the hydrologic cycle, heat is released and we warm up.
The pause has not been particularly active in terms of La Nina conditions. We have been on either side of neutral a LOT, randomly walking between El Nado and La Nada since 98, with occasional trips into El Nino and La Nina but nothing to write home about.
It seems to me we’ve been driving a long ways on a tank of gas without stopping much to refill it. Maybe getting a dollar’s worth here and there but not much more than that. Eventually, unless the skies clear up, with wind blows, and we get a full tank, we are going to run out of gas.
Is it me or are my comments getting stuck in an automatic moderation portal due to a glitch?
[Reply: It’s not you, it is WordPress. ~mod.]
“From satellite data, for example, scientists know that the Arctic region in particular has become warmer over the past years, but because there are no weather stations in that area, there are measurements that show strong upward fluctuations. ”
Belief without evidence is faith.
As the sun’s magnetic activity affects the climate? Sufficient to see how ozone affects the polar vortex. Visible shift at an altitude of about 30 km.
http://www.cpc.ncep.noaa.gov/products/stratosphere/strat_a_f/gif_files/gfs_t10_sh_f00.gif
http://www.bartol.udel.edu/~pyle/thespnplot.gif
Nobody (rational) doubts that increasing CO_2 will have a net positive effect on the average temperature.
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You and I disagree on this one point……we really do not know that…one way or the other
Pamela Gray says:
August 19, 2014 at 9:40 am
Is it me or are my comments getting stuck in an automatic moderation portal due to a glitch
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I think so..I quoted you earlier…and it went into moderation
testing it again here
nope…didn’t do it that time Pamela
““When pension funds invest the pension capital in shares, they expect to generate a profit in the long term.” At the same time, they are aware that their investments are exposed to price fluctuations and that performance can also be negative in the short term.”
Brilliant! A climate scientist uses the expectations of pension funds as an analog for global warming models. Perhaps he is unaware that massive numbers of pension funds are going belly up? Additionally, while he correctly notes that pension fund performance can also be negative in the short term he fails to note that performance can be negative in the long term, too. Some stocks (Solyndra anyone?) go bankrupt.
I can offer a simpler explanation for ‘the pause’: The sensitivity to GHG forcing calculated by the models is much too high. Were he around today, I suspect William of Ockham would agree.
The press release is disingenuous at best: the “adjustments” of Arctic temperatures (Cowtan and Way), even if correct, and that is by no means certain, make only a very small difference in the measured rate of global warming. The influence of ENSO, solar intensity, and volcanic aerosols are similarly overstated in the release. Yes, there is some effect from all those factors, just as there was the opposite effect from those same factors during the 1970’s to ~2000, which exaggerated the measured warming. There is no reasonable explanation for the divergence between models and reality save for that most of the models are far too sensitive to GHG forcing. The models project too much warming due to a combination of erroneous strong positive cloud feed-backs, overestimated ocean heat accumulation, and grossly overstated historical aerosol offsets.
Whether dragged kicking and screaming, or pulling on their big-boy pants and admitting they have long overestimated climate sensitivity, climate scientists are going to ultimately have to accept reality. It will be best for them, and more importantly, for people everywhere, if that happens sooner rather than later. The contortions and histrionics by many ‘policy advocates’ to maintain the plausibility of warming driven catastrophe are mildly entertaining (Huber and Knutti is one of many risible ‘explanations’ already published), but the economic damage done by refusing to accept the ever growing probability of low sensitivity to GHG forcing is no laughing matter. Foolish public policy, justified by climate science scare-stories of doom, causes real and immediate harm, especially among poor people. The longer climate scientists refuse to deal with plain reality and continue to insist on ridiculous projections of extreme warming, the less kind history will be to the entire field. It is time for whatever cool heads there may be in the field to start climbing down. That will leave only the worst of the ‘policy advocates’ high in the trees; that’s no real loss, since there is no hope of rational behavior from them under any circumstances.
Is there a list of these 31 excuses, with pointers to their WUWT articles? Maybe a “Lists” page should be added under “Resources”.
Once again — Warming is man-made, but no warming is just natural variation.
Just move on. Nothing to see here.
Everything the skeptics say is proof we are right.
This the cliff notes version of this article.
More and more this is becoming just funny.
You are describing an after-affect of moving ocean energy out of the ocean. We agree on what happens next. But that does not equate to the OP’s claim that El Niño events warm the earth. It warms the atmosphere but at the expense of cooling the ocean and of itself is a net zero change. To warm the earth there has to be a change in energy exchanged between the sun, the earth, and the universe.
Any energy put into the atmosphere is energy in a good position to leave the earth system resulting in a net cooling as a knock-on effect. I have long maintained that El Niño events are net cooling events even if it means there is a temporary warming pulse that passes through the atmosphere on the way to space. Surface energy can never be lost to space without going through the atmosphere, of course. That is not global warming – global warming happens when more energy arrives than is lost by all processes. El Niño events have to do with sequestered energy, not new energy, hence they cannot heat the earth but only move existing energy from one place to another. It can’t even be shown that sequestering energy in the oceans is evidence of global warming. As much energy may be leaving the system elsewhere. We have to look at the global energy exchange rate and we don’t have anything yet that can do that precisely.
If someone can show that an El Niño event causes incoming energy to be sequestered at a greater rate than without then I’d like to see it. This requires modulation of albedo or of GHG density, and it has to be permanent to affect the long term trend of global energy balance else it will be a simple pulse of atmospheric heat, much of which will be lost to the black soul of an uncaring universe.
Well said rgb, it is with a great deal of sadness that I note that the ETH Climazentrum is just another rent seeking agency. What was once a great institution has now decayed to a shell of it’s former brilliance. I can barely stand to read the ETH Aluminus publication these days. So much “Sozial Politik,” supported by “Wissenshaft” that doesn’t deserve that title, let alone any recognition.
Any private pension fund not seeing a rise in value for 17 years 10 months would see the person over seeing the fund investigated for fraud and the CEO overseeing that person in jail for defrauding the share holders. Public pension, the person overseeing it would get promoted and be in line for political run.
Fat change. Going forward, global cooling will accelerate,
look at the first two tables.
And there is no man made global warming
look at the last table,
http://blogs.24.com/henryp/files/2013/02/henryspooltableNEWc.pdf
Professor Knutti? You couldn’t make it up.
Anthony added new rules to the post previewer to prevent a load of BS dumped into the site as happened a couple days ago. I expect we’ll see more of the AutoMod going forward.
If it could be explained on the basis of then-current scientific understanding, then there would not be any need for these newfound, ad-hoc, straw-grasping explanations, would there asshat?
And there would not have been any discrepancy between the model predictions and the observations if the models had adequately incorporated that “current scientific understanding”, would there, asshat?
BTW, did you know that Verne Troyer (mini-me) and Sultan Kösen (Guinness record holder as tallest man on earth) are the same height? Doesn’t seem that way at first, but if you apply “climate science” methods and cut off Kösen’s legs while measuring Troyer on stilts, you will see that it is true.