There’s no predicted hotspot in the upper troposphere, and cooling of the stratosphere is now the new indicator. New paper finds “greenhouse cooling” of the stratosphere over past 52 years
A new paper published in Atmospheric Chemistry and Physics finds the stratosphere of the Northern Hemisphere cooled over the past 52 years due to the increase of greenhouse gases. The paper suggests that stratospheric cooling is a “more suitable” signal of anthropogenic global warming than trying to find a mid-troposphere hot spot (which was previously considered to be the definitive “fingerprint” of man-made global warming, but still has not been found despite millions of weather balloon and satellite observations over the past 60 years):
According to the authors,
A major open question that still remains to be answered is whether the stratosphere can be considered as a more suitable region than the troposphere to detect anthropogenic climate change signals and what can be learned from the long-term stratospheric temperature trends. Indeed, the signal-to-noise ratio in the stratosphere is, radiatively speaking, more sensitive to anthropogenic GHG forcing and less disturbed by the natural variability of water vapour and clouds when compared to the troposphere. This is because (a) the dependence of the equilibrium temperature of the stratosphere on CO2 is larger than that on tropospheric temperature, (b) the equilibrium temperature of the stratosphere depends less upon tropospheric water vapour variability and (c) the influence of cloudiness upon equilibrium temperature is more pronounced in the troposphere than in the stratosphere where
the influence decreases with height (Manabe and Weatherald,
1967). Furthermore, anthropogenic aerosols are mainly
spread within the lower troposphere (He et al., 2008), and
presumably have little effect on stratospheric temperatures.
Another open question is whether the lower stratosphere
has been cooling in the time since a reasonable global network
became available, i.e. after the International Geophysical
Year (IGY) of 1957–1958. Such a long-lasting cooling
from the 1960s until today would need to be explained.
To what extent are the cooling trends in the lower stratosphere
related to human-induced climate change? Has the
cooling been accelerating, for instance at high latitudes in
winter/spring due to ozone depletion? Has it been interrupted
by major volcanic eruptions and El Niño events (Zerefos et
al., 1992) or large climatological anomalies.
This study addresses those questions and presents a new
look at observed temperature trends over the Northern Hemisphere from the troposphere up to the lower stratosphere in a search for an early warning signal of global warming, i.e. a
cooling in the lower stratosphere relative to the warming in
the lower atmosphere.
Further, many warmists claim any source of warming including solar activity, cloud changes, ocean oscillations, etc. would cause a mid-troposphere “hot spot” and overlying cooling of the stratosphere, and would not necessarily be a signal or “fingerprint” of anthropogenic global warming.
The authors also find from 1958-1979 the lower troposphere either slightly cooled or remained unchanged, followed by significant warming 1980-2010:
From 1958 until 1979, a non-significant trend (0.06 ± 0.06 °C decade−1 for NCEP) and slightly cooling trends (−0.12 ± 0.06 °C decade−1 for RICH) are found in the lower troposphere. The second period from 1980 to the end of the records shows significant warming (0.25 ± 0.05 °C decade−1 for both NCEP and RICH). Above the tropopause a significant cooling trend is clearly seen in the lower stratosphere both in the pre-1980 period (−0.58 ± 0.17 °C decade−1 for NCEP, −0.30 ± 0.16 °C decade−1 for RICH and −0.48 ± 0.20 °C decade−1 for FU-Berlin) and the post-1980 period (−0.79 ± 0.18 °C decade−1 for NCEP, −0.66 ± 0.16 °C decade−1 for RICH and −0.82 ± 0.19 °C decade−1 for FU-Berlin).
Thus, although it appears the stratosphere may be cooling, and this could be due to increased greenhouse gases, there is still no evidence of a mid-troposphere “hot spot” predicted by climate models. The slight cooling to no change of lower tropospheric temperatures from 1958-1979 found by this paper also don’t support AGW theory since CO2 levels rose ~7% during that period.
The paper:
Atmos. Chem. Phys., 14, 7705-7720, 2014
www.atmos-chem-phys.net/14/7705/2014/
doi:10.5194/acp-14-7705-2014
C. S. Zerefos, K. Tourpali, P. Zanis, K. Eleftheratos, C. Repapis, A. Goodman, D. Wuebbles, I. S. A. Isaksen, and J. Luterbacher
Abstract
This study provides a new look at the observed and calculated long-term temperature changes from the lower troposphere to the lower stratosphere since 1958 over the Northern Hemisphere. The data sets include the NCEP/NCAR reanalysis, the Free University of Berlin (FU-Berlin) and the RICH radiosonde data sets as well as historical simulations with the CESM1-WACCM global model participating in CMIP5. The analysis is mainly based on monthly layer mean temperatures derived from geopotential height thicknesses in order to take advantage of the use of the independent FU-Berlin stratospheric data set of geopotential height data since 1957. This approach was followed to extend the records for the investigation of the stratospheric temperature trends to the earliest possible time. After removing the natural variability [it is impossible fully distinguish natural variability from anthropogenic] with an autoregressive multiple regression model our analysis shows that the period 1958–2011 can be divided into two distinct sub-periods of long-term temperature variability and trends: before and after 1980. By calculating trends for the summer time to reduce interannual variability, the two periods are as follows. From 1958 until 1979, a non-significant trend (0.06 ± 0.06 °C decade−1 for NCEP) and slightly cooling trends (−0.12 ± 0.06 °C decade−1 for RICH) are found in the lower troposphere. The second period from 1980 to the end of the records shows significant warming (0.25 ± 0.05 °C decade−1for both NCEP and RICH). Above the tropopause a significant cooling trend is clearly seen in the lower stratosphere both in the pre-1980 period (−0.58 ± 0.17 °C decade−1 for NCEP, −0.30 ± 0.16 °C decade−1 for RICH and −0.48 ± 0.20 °C decade−1 for FU-Berlin) and the post-1980 period (−0.79 ± 0.18 °C decade−1 for NCEP, −0.66 ± 0.16 °C decade−1 for RICH and −0.82 ± 0.19 °C decade−1 for FU-Berlin). The cooling in the lower stratosphere persists throughout the year from the tropics up to 60° N. At polar latitudes competing dynamical and radiative processes reduce the statistical significance of these trends. Model results are in line with reanalysis and the observations, indicating a persistent cooling (−0.33 °C decade−1) in the lower stratosphere during summer before and after 1980; a feature that is also seen throughout the year. However, the lower stratosphere CESM1-WACCM modelled trends are generally lower than reanalysis and the observations. The contrasting effects of ozone depletion at polar latitudes in winter/spring and the anticipated strengthening of the Brewer–Dobson circulation from man-made global warming at polar latitudes are discussed. Our results provide additional evidence for an early greenhouse cooling signal in the lower stratosphere before 1980, which appears well in advance relative to the tropospheric [assumed] greenhouse warming signal. The suitability of early warning signals in the stratosphere relative to the troposphere is supported by the fact that the stratosphere is less sensitive to changes due to cloudiness, humidity and man-made aerosols. Our analysis also indicates that the relative contribution of the lower stratosphere versus the upper troposphere low-frequency variability is important for understanding the added value of the long-term tropopause variability related to human-induced global warming.
(this post via the HockeySchtick)
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About that missing hot spot in the upper troposphere
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Joe Born,
No cooling results due to CO2 increasing the stratospheres ability to radiate heat absorbed by the O3.
As I have said were it not for the presence of significant O3 in the stratosphere CO2s absorptive properties would dominate its radiative properties all the way to the top of the atmosphere warming it to the very tippy top.
“Were there no O3…”
An atmosphere with no O3 is also a myth.
So now if you want to find global warming, look at the stratosphere, not at that troposphere whose temperature tells you if there is warming or not. And that stratospheric cooling, they think, started 51 years ago. Has it occurred to them that such changes in the earth environment demand that a causative agent be present? If there is no causative agent to start up that cooling 51 years ago we will have to decide that we are dealing with an uncaused phenomenon. That is something entirely knew to science though apparently accepted willingly by so-called “climate” scientists who wrote this article. They are of course on the trail of carbon dioxide which is their ultimate boogey-man, the root cause of global warming according to their doctrine. As I have said before, CO2 is incapable of warming the atmosphere. This warming tale started with Hansen’s announcement to the Senate in 1988 that he personally had discovered the greenhouse effect. His argument was that there had been hundred years of warming that culminated at the warmest point ever recorded in 1988. The probability of this happening by chance was only one percent so this warming could not happen by chance and had to be caused by the greenhouse effect. The problem with this argument is that thirty of these hundred years are demonstrably not greenhouse warming. You just can’t use a non-greenhouse warming to prove that the greenhouse effect exists. Nevertheless, he and IPCC have been claiming that it does exist for 26 years and getting away with it because there was no way to check it. Fortunately for us, global warming stopped 17 years ago and there has been no warming of any kind since then. At the same time, carbon dioxide has been steadily increasing without causing any of that greenhouse warming used to justify the existence of IPCC. Naturally they don’t like it and point to the fact that the Arrhenius greenhouse theory still predicts warming. That of course is true, and sufficient proof of warming to such true believers. But if a theory predicts warming for 17 years and nothing happens you are justified in tossing that theory into the waste basket of history. This leaves the warmist case without any theoretical support. Fortunately there is another greenhouse theory called Miskolczi greenhouse theory (MGT) that can handle this situation. It came out in 2007 but you don’t know about it because the warmists have successfully suppressed any mention of it. It predicts exactly what we see: there is no warming while carbon dioxide keeps going up. According to MGT carbon dioxide and water vapor, the two major greenhouse gases, establish a joint optimum absorption window in the IR which they control. Arrhenius cannot do that because it is limited to carbon dioxide alone. The optical thickness of this absorption window in the IR is 1.87, determined by Miskolczi from first principles. If you now add carbon dioxide to atmosphere it will start to absorb in the IR just as the Arrhenius theory says. But this will increase the optical thickness. And as soon as it begins, water vapor will start to diminish, rain out, and the original optical thickness is restored. The introduced carbon dioxide will of course keep absorbing but it cannot cause greenhouse warming because the removal of water vapor just balances out the warming capacity that carbon dioxide otherwise would have. It does not prevent absorption, ot simply prevents absorption from warming the atmosphere. The result is a horizontal temperature curve showing no warming while atmospheric carbon dioxide increases, just as we have now. This has several consequences. One of them is that a runaway greenhouse warming that Hansen has been babbling about is quite impossible. This explains why very high carbon dioxide in geologic history did not cause any runaway greenhouse effect. Hansen was also wrong on his Venus analogy because he was ignorant of Venusian geology but that is another story. A more mundane result is that the presence of these mixed GHGs prevents the occurrence of the enhanced greenhouse effect here on earth. It follows from this that AGW is nothing more than a pseudo-scientific fantasy, indulged in by over-eager climate scientists anxious to prove that the greenhouse effect is real.
Oops. My computer didn’t load the second set of graphs first time around. Still what is the “date” on the left side of the first graphic, it isn’t a time series as implied by the title of the graphic.
Steven Mosher says: “Stratospheric cooling is the better fingerprint.”
A central argument of the Enhanced Greenhouse Effect (remember that?) is the atmosphere warms the surface as a result of radiative physics. Basic radiative physics says the WARMING (delta T) above the surface must be greater than the WARMING at the surface (upper case to stress WARMING does not mean WARMER).
This prediction was confirmed in AR4, and the above hotspot pattern is just as it appears in AR4. AR4 also went to the length to show different patterns due to different “forcings” and made it pretty clear that only CO2 was behind the predicted hotspot.
Different researchers used terms like “vertical amplification” or “scaling factor” for the expected difference in delta-T between surface and atmosphere. Delta-T parts of the atmosphere were predicted to be 1.4 to 1.6 times delta T at the surface. This can be seen in the predicted hotspot pattern when the scale is included, and AR4 expressed the scale in degC per decade (therefore WARMING).
If it is asserted that surface temperature was “forced” up by (say) 0.7 degC over recent decades due to an Enhanced Greenhouse Effect, there is an onus to demonstrate cause and effect. The Enhanced Greenhouse Effect demands that regions of the atmosphere must have delta-T in excess of 1 degC for the same period for the above surface warming.
If this cannot be demonstrated, the hotspot hypothesis is falsified by data. The Enhanced Greenhouse Effect would also be falsified the extent it rests on the physics encapsulated in the hotspot prediction.
The Enhanced Greenhouse Effect never claimed that surface warming would be CAUSED (emphasis) by atmospheric cooling. The basic physics would be completely wrong. Stratospheric cooling therefore cannot be a better indicator of the Enhanced Greenhouse Effect.
The Tropospheric Hotspot has become the Tropospheric Hot Potato. Enjoy the spectacle as the fur starts to fly.
In theory, the stratosphere cooling can be caused by troposphere heating. Can the stratosphere respond the same way to trop cooling? Or is it always negatively correlated?
Climate Weenie,
“An atmosphere with no O3 is also a myth.”
Your obtuseness is astounding. Its a hypothetical designed to isolate the greenhouse gas effect.
They should have just named that paper “Even when we’re wrong, we’re always right.”
Tom T.: “No cooling results due to CO2 increasing the stratospheres ability to radiate heat absorbed by the O3.”
Thanks a lot; that clears it up (at least if you meant a comma after “No”).
Joseph Murphy,
There is no theory. In reading how these authors parse their words its clear that they know full well the stratospheric cooling and tropospheric warming are not physically related, they only share the same cause.
When you know that the parsing of words in this paper stands out like sore thumb.
Zerefos et al:
Crooks and Gray, 2005; Austin et al., 2009). It is well known that significant transient warming events occurred in the stratosphere following the volcanic eruptions of Agung (March 1963), El Chichón (April 1982) and Mount Pinatubo (June 1991), and these can substantially influence
temperature trend estimates (especially if the volcanic events occur near either end of the time series in question). The common approach in order to avoid a significant influence on
trend results is to omit data for 2 years following each eruption in the regression analysis. In order to investigate the role played by stratospheric aerosols, we include terms to account
for the influence of stratospheric aerosol variability, using the Stratospheric Aerosol Optical Depth (Sato et al., 1993) as an index in the regression model.
>>>
Well if they are only modelling the volcanic effect as a temporary warming and think they can avoid the periods affected by avoiding two years after the eruptions, their model fitting will be severely wrong.
The other problem is they are fairly arbitrarily throwing in a bunch of possible “natural” forcing into a multivariate regression. This kind of thing can be done on any data but whether the result is just a spurious ‘best fit’ is another questions.
This fundamentally assumes a direct correlation with no lag , ie almost instantaneous equilibration. That is nonsense:
http://climategrog.wordpress.com/?attachment_id=884
The result will be spurious attribution due to false correlations. For example the volcanic event occur at roughly 10y intervals and approximately correspond to SSN peak activity.
the post eruption cooling cannot correlate to AOD they used so what will that be falsely attributed to.
There is just so much that is wrong with their methods it’s hard to know where to start.
This paper reminds me a little of Marcott, where when pressed I’m sure the authors will state ‘well we never really said that in the paper.’
Of course getting the reader to assume it was the goal of the paper.
Theo Goodwin says:
August 4, 2014 at 10:44 am
gregfreemyer says:
August 4, 2014 at 10:05 am
===================================
===================================
Notice that you have introduced a claim that does not belong to radiation theory alone. You appeal to the relative density of the air. There is not a lot of water vapor in the stratosphere. There is a huge amount of water vapor in the troposphere. So, your explanation appeals to factors that fall outside of radiation theory. Radiation theory alone does not imply that radiation passing through a dense cloud of CO2 will cool the area above it that is less densely populated with CO2.
The important point here is that the good reputation of radiation theory cannot be used to support the claim that high concentrations of CO2 in the troposphere cool the stratosphere. Some other claim must be added. Maybe a claim about relative concentrations of water vapor. Your rather generic claim is about the relative density of air at various heights.
===================================
Note: I may have misused the term density. You may be taking it as grams per volume. I meant it as molecules per volume.
My claim has zero to do with water vapor. It has purely to do with the density (number of molecules per volume) of all molecules in the stratosphere versus the density of all molecules in the lower troposphere. I should also have said it has to do with the speed of the molecules, and possibly the average momentum of the molecules, thus the temperature would also need to be taken into account.
Regardless, the likelihood of a collision exciting a GHG molecule in a GHG molecule / random molecule collision has little to do with the presence of water vapor in the neighborhood.
Similarly, the likelihood that an excited GHG molecule has time to spontaneously emit before being involved in a subsequent collision has nothing specific to do with water vapor being in the neighborhood. A collision with any molecule will do the job just fine.
The basic issue is that per the radiative theory a GHG can:
– convert photons to kinetic energy (heat the atmosphere)
– convert kinetic energy to photons (cool the atmosphere)
– absorb and re-emit photons (slow down the transfer of energy)
All 3 of those processes are going on simultaneously and you have to perform a statistical mechanics analysis of the molecules and photons to figure out what will happen with different situations.
My statement is that the statistical mechanics analysis when applied to the stratosphere will show that CO2 acts to cool the stratosphere and that an increasing density ( CO2 molecules per volume) or increasing density (CO2 molecules per million molecules) will result in a greater cooling and thus a cooler stratosphere.
The stratosphere should cool to the point that the lower temperature causes less of the special collisions that excite CO2 molecules and thus equilibrium is achieved.
To the best of my knowledge, water vapor has nothing to do with the above.
It is further my opinion that the above is well agreed physics and neither warmers nor most sceptics should take issue with it.
Tom T, you’re not going to get rid of O3,
so you’re not going to get rid of the temperature profile induced by O3.
Therefore, the hypothetical is not of much use.
Climate Weenie,
Its very much of use. You simply don’t get it. The hypothetical allows us to see how CO2’s long wave absorptive properties should effect the stratosphere. CO2s long wave absorptive properties AKA greenhouse gas effect should warm the stratosphere not cool it. However, due the presence of O3 absorbing shortwave radiation CO2s radiative properties dominate and cool the stratosphere.
I know you think you have an argument but you don’t.
The hotspot, my friend, is blowing in the wind. The hotspot is blowing in the wind.
Stratospheric cooling is consistent with greenhouse gas warming by some theories:
Complicating things, is the factor related to the ozone layer(located in the stratosphere). If it has shrunk, absorbing less solar radiation, then that layer would become colder than when there was more solar radiation absorption.
Regarding CO2. It absorbs and also emits long wave radiation.
As the absorption of LW radiation by CO2 becomes stronger in the troposphere(even approaching the point of saturation of some bands?) you might expect there to be less LW radiation in those bands to be absorbed by CO2 at higher altitude…….. in the lower stratosphere. This is what many think
http://www.atmosphere.mpg.de/enid/20c.html
But ren(and others)think that any changes in the temperature of the stratosphere must come from changes in ionization of solar and cosmic radiation as they interact with the chemistry of the ozone layer.
If this were the exclusive reason for the colder temperatures, then it’s not a good signature for greenhouse gas warming below.
They both make sense to me and it could be a combination of the two or mainly just one of them that have resulted in cooler stratospheric temps.
However, the main problem with having confidence, is that we don’t have accurate measurements that go back long enough to compare temperatures in the stratosphere in the past with recent temperatures there.
Without a temperature gradient, with more detailed information, the post doesn`t give much understanding of the dynamics. What matter is the emission hight, I think. What altitudes are waming and cooling?
Mike Maguire,
“Stratospheric cooling is consistent with greenhouse gas warming by some theories:”
In the same sense plant fertilization is consistent with greenhouse gas warming by some theories i. CO2 causes both but the two aren’t physically related. They are different physical phenomenon caused by increased CO2.
gregfreemyer says:
August 4, 2014 at 11:28 am
Theo Goodwin says:
August 4, 2014 at 10:44 am
gregfreemyer says:
August 4, 2014 at 10:05 am
Regardless, the likelihood of a collision exciting a GHG molecule in a GHG molecule / random molecule collision has little to do with the presence of water vapor in the neighbourhood.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
It’s a long time since I took Physics but if Water Vapour is the major Green House Gas, why is it excluded as a GHG above? Why wouldn’t a collision between any GHG – CO2 or CH4 or H2O molecule have an effect? I am sure this has been discussed before, but give me an idea of why it has to be some “chosen” gas. Thanks.
The simple fact of the matter is that the addition of any molecule be it CO2 or water vapor that makes the stratosphere more dense will cool the stratosphere because of an increase in molecular collisions with O3 that has been excited by absorbing shortwave radiation.
In a practical sense all CO2 does in the stratosphere is serve as a radiator for O3.
My two cents: increased greenhouse gases in the stratosphere leads to greater IR radiation to space from the atmosphere itself. The stratosphere is more “optically thin” than the troposphere.
Yesterday, before this study came out, the tropical hotspot was the official global warming fingerprint.
Today, after this paper, a cooling stratosphere is the official global warming fingerprint.
See? Tweedle-dee and Tweedle-dum had nothing that these guys don’t have. It is called climatespeak.
Another item to complicate things. What if the cooler stratosphere is from greenhouse gas warming below from CO2 but CO2 absorption is becoming saturated in the troposphere?
In that case, stratospheric cooling from just this effect, would also be bottoming out as you can’t decrease the amount available to absorb in the stratosphere to less than 0.
Funny thing about all this, is that we keep getting all these new papers and new studies with breaking news in a field where “the science is settled”.
Yeah, I know, this one can be seen as more evidence for tropospheric warming by greenhouse gases(even as the disparity of observations vs global climate model temp projections grows).
Maybe if we could just bring the hot spot that should be in the mid tropospheric tropics out of hiding in the deep oceans(:
Tom T says:
August 4, 2014 at 11:49 am
CO2s long wave absorptive properties AKA greenhouse gas effect should warm the stratosphere not cool it. However, due the presence of O3 absorbing shortwave radiation CO2s radiative properties dominate and cool the stratosphere.
==========
Not quite sure what you are saying:
O3 has absorption/emission bands of 600-800 and 950-1200 wavelengths/cm
CO2 has 540-800, 850-1250, and 2100-2400 wavelengths/cm
Clearly there is significant overlap except in the 2100-2400 band (the shortwave band).
Why do you state that in the stratosphere CO2’s 540-800 and 850-1250 bands are warming bands, but the 2100-2400 band is a cooling band?
Note that I’m not arguing, I’ve just not been exposed to that statement before. I will repeat that to figure out if a individual band is a warming or cooling band requires a statistical mechanics analysis, but I can easily see where the bands could give opposite results for the same environment.