Guest essay by Eric Worrall
A paper published in Nature claims an estimated 7 – 13c / doubling of CO2 – an estimate so wild it has drawn criticism from NASA GISS chairman Gavin Schmidt.
Evolution of global temperature over the past two million years
Reconstructions of Earth’s past climate strongly influence our understanding of the dynamics and sensitivity of the climate system. Yet global temperature has been reconstructed for only a few isolated windows of time1, 2, and continuous reconstructions across glacial cycles remain elusive. Here I present a spatially weighted proxy reconstruction of global temperature over the past 2 million years estimated from a multi-proxy database of over 20,000 sea surface temperature point reconstructions. Global temperature gradually cooled until roughly 1.2 million years ago and cooling then stalled until the present. The cooling trend probably stalled before the beginning of the mid-Pleistocene transition3, and pre-dated the increase in the maximum size of ice sheets around 0.9 million years ago. Thus, global cooling may have been a pre-condition for, but probably is not the sole causal mechanism of, the shift to quasi-100,000-year glacial cycles at the mid-Pleistocene transition. Over the past 800,000 years, polar amplification (the amplification of temperature change at the poles relative to global temperature change) has been stable over time, and global temperature and atmospheric greenhouse gas concentrations have been closely coupled across glacial cycles. A comparison of the new temperature reconstruction with radiative forcing from greenhouse gases estimates an Earth system sensitivity of 9 degrees Celsius (range 7 to 13 degrees Celsius, 95 per cent credible interval) change in global average surface temperature per doubling of atmospheric carbon dioxide over millennium timescales. This result suggests that stabilization at today’s greenhouse gas levels may already commit Earth to an eventual total warming of 5 degrees Celsius (range 3 to 7 degrees Celsius, 95 per cent credible interval) over the next few millennia as ice sheets, vegetation and atmospheric dust continue to respond to global warming.
Read more: http://www.nature.com/nature/journal/vaop/ncurrent/full/nature19798.html
Gavin Schmidt’s response;
Climate change study accused of erring on rising temperature predictions
…
He (Gavin) said he did not think the conclusion was correct.
“In fact, I’m pretty certain that is an incorrect calculation,” he said.
“The ratio that gave that, which was the very high sensitivity that she calculates, comes from a correlation between temperature and the carbon dioxide and other greenhouse gases from the ice cores, but as we all know, correlation does not equal causation.
“And in this case, the causation is the orbital wobbles of the Earth’s climate that are controlling both the temperature and the carbon dioxide at the same time and so that’s giving you an exaggerated view of how carbon dioxide affects temperature directly.”
However, Dr Schmidt welcomed the temperature history provided by the study, which analysed about 60 different sediment cores.
…
Read more: http://www.abc.net.au/news/2016-09-27/climate-study-under-fire/7881740
It is nice to know there are climate sensitivity estimates which even NASA thinks are implausibly high.
It seems the surface albedo feedback was greater when Earth was more glaciated, and there was more variability in the amount of sunlight reflected away by ice and snow as a result of temperature change.
Surface albedo is probably a wicked contributing factor for glacial periods, but it takes hundreds or maybe even thousands of years for enough ice to build up before that albedo factor comes into play. Higher rates of cloud albedo and snow deposition, trending together over thousands of years are necessary to create NH ice sheets. Summer clouds reduce the melt season and winter clouds keep the troposphere warmer (but not so warm as to turn snow to rain) and contribute more snow. Now, how do we explain where thousand year trends in more moist cloudy skies in the NH with a healthy evaporation pump in the tropics?There MUST be lots of H2O condensing aerosols in play, far more than are in play during the inter-glacial periods.
What could explain long periods of higher than normal particulates and aerosols in the atmosphere? A long period of volcanic activity is one way. An extended period of low atmospheric CO2 that’s low enough to cause plant death in some areas, thereby causing desertification of vast areas of land that then produce dust storms, is another possible explanation. This would provide an excellent explanation for cyclical behavior. As CO2 is released by warming oceans, the source of aerosols decreases. Later, as the Earth greens from the extra CO2, it’s removed from the atmosphere over time, causing another starvation period. The Svensmark GCR theory could explain it, too, perhaps.
In my opinion, these are the areas climate science needs to be investigating.
Sorry, my glacial – inter-glacial hypothesis in three parts. As the NH glacial ice builds, and surface albedo feedback kicks in, the Earth finally cools enough to turn off some tropical evaporation pump. This starves the atmosphere of water vapor and so now, even with lots of dust and aerosols present, the skies clear, and the sun begins to shine. As ice sheets begin to melt, ocean currents are disrupted by fresh water incursions and salt water based density changes. Until ocean convection stabilizes, the evaporation and convection of water vapor into the NH atmosphere is slowed. But insolation is increased and ice keeps melting. Once the ice sheets have mostly melted, the oceans warm and emit CO2 to allow the desert areas to green, turning off most of the dust.
Mickey,
An interesting observation of the yearly accumulation of ice in the cores is much larger during interglacial periods than during glacial periods. The blue line is temperature and the gray line is the number of years per ‘bag’, where each bag is a fixed length section of the core. Notice the unmistakable and near perfect correlation.
http://www.palisad.com/co2/ic/d_width.gif
The solid black line is deltaW/deltaT, where W is the number of years per bag and T is the temperature. Notice the characteristic change in dW/dT both before and after each period of change. Only 200K years are plotted and the data was smoothed to a centered 2200 year average.
There are a lot of other interesting plots in this directory covering both DomeC and Vostok data. Replace ‘d_width.gif’ in the link with ‘v_width.gif’ and you can see the analysis for Vostok data over the same interval. Change the link to point to just the directory (remove the d_width.gif part) to see the other plots in this directory.
They just forgot the decimal point and meant 0.7 – 1.3 degrees. But even that is about 5 times too high.
Too true. A factor of 10X seems appropriate for error, after all the IPCC accepts 300% in estimating climate sensitivity currently.
My thought too, Ed. My guess is they’ll pop in that decimal point and try and pass it off as a “mistake” (and still be wrong) when the objections get too loud.
The current average surface temperature is 288K which emits about 390 W/m^2 per Trenberth. If we increase the surface temperature by 13C, those emissions increase to 465 W/m^2 for a 75 W/m^2 increase. For the surface to emit that much more, it must be absorbing that much more, otherwise, the surface will cool.
The fact that anyone can think that this much change from the 3.7 W/m^2 of CO2 ‘forcing’ is even remotely possible, illustrates what can only be characterized as the insane belief that Conservation of Energy need not apply to the climate. That this insanity showed up in a main stream journal is the clearest indication yet that peer review is horribly broken.
This absurd claim takes the obfuscation of specifying sensitivity in the non linear units of degrees per W/m^2 of forcing, rather than the mostly linear units of W/m^2 of surface emissions per W/m^2 of forcing, to a place so far beyond reason it’s absurd.
The measured sensitivity is about 1.6 W/m^2 of surface emissions per W/m^2 of forcing which is less than 0.3C per W/m^2. The consensus sensitivity of 0.8C per W/m^2 sounds plausible enough until its expressed as 4.3 W/m^2 of incremental surface emissions per W/m^2 of forcing where you must ask where are the extra 3.3 W/m^2 coming from?
Claiming a sensitivity of 20 W/m^2 of incremental surface emissions per W/m^2 of forcing is so insane, even Gavin Schmidt rejects it. Too bad he can’t apply the same logic that makes 20 W/m^2 of surface emissions per W/m^2 of forcing wrong to the equally absurd claim that 1 W/m^2 of forcing will increase surface emissions by 4.3 W/m^2.
As far as I can make out, the climatist model postulates that “greenhouse gases” obstruct the flow of heat from the surface to space. Never mind that long wave radiation is a small minority carrier of heat through the troposphere. So IR transfer of heat through the troposphere could be cut to zero and it would take only a minor increase in convection, evaporation, and conduction to carry the heat.
“climatist model postulates that “greenhouse gases” obstruct the flow of heat from the surface to space”
But they also postulate that most, if not all, of the obstructed heat is returned to the surface and fail to accommodate the fact that what energy the atmosphere absorbs (temporarily stores) by obstructing surface emissions eventually leaves the atmosphere into space and is returned to the surface is roughly equal proportions.
They also put too much emphasis on convection and non EM forms of energy, which by definition do not contribute to the planets radiative balance or affect the surface sensitivity to forcing.
This paper is an own goal for warmunists. The calculation is clearly logically wrong; even Gavin Schmidt says so. Correlation does not equal causation, and past CO2 lags delta T by 800 years yhanks to thermohaline circulation and Henry’s Law. Same mistake Gore made in Incomvenient Truth. The erromeous result clearly implies a present rate of warming that simply does not exist in the absence of a massively delayed pipeline explanation. That makes it internally contradictory, separate evidence that Gavin is correct. Finally, it got through peer review at Nature, showing only how abysmally poor climate peer review is even in themrop journals. Becomes a powerful simple talking point about ‘settled science’ and the ‘climate literature’, shredded in the blogosphere in a mere day.
Mixed feelings.
On the one hand it is concerning it passed peer review and was published, but on the other hand, if some people think a few seconds and say “wait, we already doubled and got less than .8, how do we get to 9???”, I’d say it damages their cause somewhat…
Wow though. Is there any other science field where observations can just be ignored?
One would think that any responsible scientist would make sure that such an important conclusion as:
“A comparison of the new temperature reconstruction with radiative forcing from greenhouse gases estimates an Earth system sensitivity of 9 degrees Celsius (range 7 to 13 degrees Celsius, 95 per cent credible interval) change in global average surface temperature per doubling of atmospheric carbon dioxide over millennium timescales.”
was at least consistent with paleoclimate science data.
It is not.
If we look at the best scientific data of climate proxy reconstructions of atmospheric CO2 levels and global temperatures surrounding the transition from Earth’s last glacial period to the present Holocene interglacial period (an interval from about 18,000 years ago to about 10,000 years ago . . . thus meeting the criteria of “over millennium timescales”), we find that Earth’ southern hemisphere average temperature rose by about 8 deg-C and Earth’s northern hemisphere average temperature about rose by 14 deg-C while global atmospheric CO2 levels rose by only 39% (from 190 ppm to 265 ppm, based on Antarctica EPICA Dome-C core data). Given that this range of 8 to 14 deg-C is very comparable to the range of 7 to 13 deg-C in the above quote and given that a 39% change is far different than a 100% change (a doubling) in CO2, the conclusion quoted above is, de facto, false.
QED.
How many times do they want to prove they haven’t a f***ing clue?
RWt, hopefully as many as possible. Makes ridicule that much more frequent and compelling.
I think Messrs Lewandowsky, Mann, Brown and Friedman should be chastising Gavin Schmidt and others for having the audacity to challenge this peer-reviewed research on blogs and not through the proper channels.
http://jspp.psychopen.eu/article/view/604/html
I wonder if he’s one of those conspiracy nutters you hear so much about…
I commit myself to never exceeding 55 mph in order to minimize CO2 auto emissions and stabilize the climate. Oh, sure, you may say I’m a dreamer, but I’m not the only one. Who among the warmist dreamers out there will join me in my noble climate crusade?… Hello?
I will promise never to drive less than 55 just because 55 is my MPG optimum and I like to get my best mileage driving around town and past schools
So….how long until I can go outside with a glass canister of CO2 gas and use use it to barbeque by holding it above the grill on a sunny day?
It’s that Evil Fossil Fuel industry, isn’t it? They are forcing us to use propane when we could just capture CO2 for all our renewable energy needs.
/sarcasm
If Gavin Schmidt is the answer…how badly off was the question?
Apparently, and it is a given truth since IPCC was created, climate is defined by one parameter (temperature), one variable (CO2 concentration), and one only function: ΔT=f([CO2]).
I once saw a chart linking UFO sighting rises to temperature rises. Matched perfectly.
This isn’t about science. It is a sales pitch. Just look at the EPA program she works for. Her job is to sell windmills with no market justification, or, in her own words, “remove market barriers … for renewable energy.” If you are a paid salesperson for a product no one wants or needs, you either see the writing on the wall and move on, or you disingenuously try to sell the product by creating the perception of need (like the whole-life insurance policy salesmen of old). In her world, CO2 sells, and the higher the “fever”, the greater the demand for her products. You see the same behavior in some DOE program managers. Their jobs and contacts become vested in their given technologies, and they soon drift away from being objective managers toward becoming technology promoters, creating rosy sales pitches underwritten and supposedly validated by the U.S. government. Then they leave for high-paying jobs at those technology companies they’ve been promoting.
So this paper is nothing more than the sales pitch of a windmill sales-hominid?
Next few millennia?
5 degrees C in the next few THOUSAND years?
95% credible?
Oh! The Stupid, it burns.
I was about to say most odd, but in this paper that’s going some, but there isn’t a single AGW theory that shows millenia drag. That’s saying something as well. Isn’t it widely accepted to be a mere hours, max a few weeks, including water vapour feeeback?
Actually, several papers and different methods show sensitivity over 2/3 done in 10-15 years, the rest (land albedo) in maybe a century. Biggest uncertainty is ocean thermal inertia.
95% credible, 100% ludacris
Some people think that if they don a white lab coat , they can say anything.
So the idea of the paper is to grab CO2 climate sensitivity from proxy records assuming all temperature change is from CO2 and nothing else.
So – what value do we get from this data around the time of the Permian extinction:
http://s17.postimg.org/93bes725b/Permian_Extinction_Temp_CO2_Zoom_In.png
Just read Dr Schmidts’ comments in full. I even felt a little sorry for him. He knows this is a big own goal for settled science.
I have a database of all CO2 and Temperature estimates going back 750 million years.
The actual calculated CO2 sensitivity is really + / – 40.0C.
Just the last 5 million years but there are over 5,000 datapoints in this chart.
http://s10.postimg.org/4u651ipix/CO2_sensitivity_last_5_Mys.png
Now if one could ALSO figure out what Earth’s Albedo was in all those datapoints, then you could actually answer the question. Earlier Mosher said that CO2 was only responsible for one-third of the ice age temperature change of 5.0C. Well that all depends on what the ice-sheets and desert and cloud cover changes did to the Earth’s Albedo. The one-third CO2 impact is based on an absurdly low estimate of the Albedo change. You can make up any number you want in climate science if you do not objectively answer the Albedo question. [The actual ice age changes are -4.25C from ice Albedo and 0.75C from CO2).
I have always been concerned that gas measurements of ice cores are made assuming that the gas concentrations are very close to the concentrations that were once in the air when these bubbles were trapped in the ice. This may have been a reasonable assumption when the ice was in the icepack or glacier from which it was pulled. My concern is that the ice cores are stored for some time under conditions which are neither the same temperature, nor the same pressure as the original ice conditions. This being the case, I would expect some diffusion (Fickian or Knudsen) to occur between the time that the ice core is cut and pulled up from the ice pack or glacier and the time at which it is analyzed. Diffusion is bidirectional therefore, if my concern is correct, the gas analyses will indicate a CO2 level which could be higher or lower than it was when it was in the ice mass from which it was taken. Therefore, I am concerned that conclusions are being made based on incorrect estimates of the paleohistorical CO2 levels.
It only takes about 30 years for glacial snow to turn into solid glacial ice that is stable afterward for a very long time.
In Antarctica at the summits. that ice keeps getting pushed down for about 800,000 years until it becomes too distorted to provide accurate atmospheric bumbles etc. Greenland is only 15,000 years or so before the ice is too distorted to provide accurate atmosphere levels. The dO18 isotopes on Greenland are still good for 94,000 years in most cores or 130,000 years In the new NEEM core but Antarctica dO18 is still good out to 800,000 years in the summit cores.
But you raise a valid point about being careful if the ice-sheet cores provide valid evidence.
Beyond 800,000 years, it is mainly ocean cores that are used or continental shelf cores when one gets past 200 million years. Overall, there is a strange trend that develops in that the dO18 isotopes change through time probably because of diagenesis as water flooding occurs over time. This appears to be close to a straight line change through time and thus the dO18 isotopes are normally adjusted for this using a straight line method (unless one is a climate scientist trying to snow the public which happens often enough).
If our climate were that sensitive to CO2 then one would expect that the increase in CO2 over the past 30 years would have caused a noticeable increase in the environmental lapse rate in the troposphere but that has not happened. The previous interglacial period was warmer than this one with more ice cap melting and higher sea levels yet CO2 levels were lower than today. Apparently there is something other than CO2 that needs to be accounted for. The data shows that warmer temperatures cause more CO2 to enter the atmosphere because warmer oceans cannot hold as much CO2 as cooler oceans but there is no real evidence that the additional CO2 has caused any global warming. If greenhouse gases cause warming then the majority of the discussion needs to be about the primary greenhouse gas, H2O, but such is not the case. One needs to consider not just CO2 but total levels of greenhouse gases in the atmosphere, especially H2O. Another problem is that the 33 degrees C that the Earth’s surface is warmer because of the atmosphere can all be accounted for by the convective greenhouse effect as derived from first principles. An additional radiant greenhouse effect caused by so called greenhouse gases has yet to be detected anywhere in the solar system including Venus and the Earth.
And yet one cant get failed replications published in these same journals, shows something is seriously wrong with science publication.
For the record: Gavin Schmidt’s website, RealClimate.org, previously endorsed this very high climate sensitivity to CO2. Or about 5/6 of it, anyway.
http://www.realclimate.org/index.php/archives/2004/12/co2-in-ice-cores
“What does the lag of CO2 behind temperature in ice cores tell us about global warming?
This is an issue that is often misunderstood in the public sphere and media, so it is worth spending some time to explain it and clarify it. At least three careful ice core studies have shown that CO2 starts to rise about 800 years (600-1000 years) after Antarctic temperature during glacial terminations. These terminations are pronounced warming periods that mark the ends of the ice ages that happen every 100,000 years or so.
Does this prove that CO2 doesn’t cause global warming? The answer is no.
The reason has to do with the fact that the warmings take about 5000 years to be complete. The lag is only 800 years. All that the lag shows is that CO2 did not cause the first 800 years of warming, out of the 5000 year trend. The other 4200 years of warming could in fact have been caused by CO2, as far as we can tell from this ice core data.
The 4200 years of warming make up about 5/6 of the total warming. So CO2 could have caused the last 5/6 of the warming, but could not have caused the first 1/6 of the warming.
[..]”.
[my emphasis]
And in our estimation, there is no causation whatsoever. Co2 concentrations are merely following temperature via oceanic absorption and outgassing.
Modulation of ice ages via precession and dust-albedo feedbacks.
http://www.sciencedirect.com/science/article/pii/S1674987116300305