CO2 did not drive the rapid warming of the 20th century.
Story submitted by Stan Robertson
The difference between a good idea and a bad idea is often a quantitative matter. For example, many people would think it a good idea to replace internal combustion engines with electric motors. But if the intent is to reduce the burning of fossil fuels then switching to electric motors would not help unless the electricity was generated without burning fossil fuels. Some people think that it has been a good idea to use corn to produce ethanol for a fuel, however, I am not one of them because the energy return on investment is either negative, or minuscule at best. From the standpoint of greenhouse gas emissions, it is a horrendous loser. It may be a biofuel and cleaner burning, might help ameliorate ozone problems and etc, but considering that nearly a gallon of oil is consumed in addition to the gallon of ethanol produced and burned, it is a quantitative loser. (Not that I care at all about the CO2.)
One of the ideas that seems to be widely believed is that human produced greenhouse gases, chiefly CO2, has dominated the warming of the earth in the last century. It is a simple quantitative matter to show that this is completely false.
According to the calculations of the UN IPCC, a doubling of the atmospheric concentration of CO2 (with an accompanying rise of other greenhouse gases) would reduce the outgoing infrared radiation from the earth by a net 2.7 watt/m^2 at the top of the atmosphere. This is known as the “climate forcing” that will occur along with a doubling of the CO2. This is a relatively straightforward, but messy calculation. I have repeated the IPCC calculation for CO2 and obtained a larger number, but after including the IPCC adjustments for other greenhouse gases and the effects of sulfate aerosols accompanying coal burning, we agree. It is important to note that the surface temperature increase that will accompany the CO2 is proportional to the logarithm of the CO2 concentration. Thus while CO2 concentration is increasing exponentially with time, the temperature only increases linearly.
In order to maintain equilibrium with the incoming UV/VIS radiation received by the earth, the surface temperature would need to increase enough to allow it to radiate an additional 2.7 watt/m^2 at the top of the atmosphere after any CO2 doubling. At a nominal surface temperature of 15 C (288 K), the earth surface radiates about 390 watt/m^2 on average, but the radiation that exits the top of the atmosphere is only 240 watt/m^2. Thus the earth would need to produce an additional (390/240)x2.7 watt/m^2 = 4.4 watt/m^2 at the surface in order to offset the direct effect of doubling the atmospheric CO2. At 288 K, the earth radiates an additional 5.4 watt/m^2 per 1C of temperature rise. Thus the direct effect temperature increase of a CO2 doubling would be 4.4/5.4=0.8 C.
At the present 0.5% per year rate of increase of CO2 it will take about 140 years to double its concentration. But as we all know, a 0.8 C temperature increase in 140 years is not the result that the UN IPCC is alarmed about. The IPCC climate models include large positive feedback effects that raise their expected temperature increase into the range 2 – 4.5 C, with their most probable value at about 3 C.
There are four main arguments against this: (1) We have already had half of a 2.7 watt/m^2 climate forcing since pre-industrial times. That has been accompanied by only 0.8 C temperature increase. As shown below, there are reasons for believing this to be due primarily to natural causes. (2) There is no evidence that confirms the existence of any large feedback effects since the end of the last deglaciation. (3) The rate of temperature increase within the past century has been within the bounds of normal climate variability and (4) as shown below, the heating effect of CO2 has been quantitatively inadequate to explain the actual warming that has occurred in the last century.
There have been two periods of rapid warming that account for most of the warming that occurred in the last century, as shown below.
Let’s examine the first of these rapid warming periods first. By 1944, the atmospheric CO2 concentration had increased from the pre-industrial level of about 280 ppm up to 310 ppm. At that time the concentration was increasing at a rate that would require about 600 years to double. The fraction of a doubling climate forcing that would have occurred by 1944 would have been log(310/280)/log(2)=0.15 and this would have contributed at a rate of 0.15×2.7 watt/m^2 per 60 decades, or 0.0068 watt/m^2 per decade. It’s direct warming effect at the surface would thus be only (390/240)x(0.0068 watt/m^2 per decade)= 0.01 watt/m^2 per decade. This would have raised the temperature by (0.01 watt/m^2 per decade) /( 5.4 watt/m^2 /C) = 0.002 C per decade. This is such a pitifully small fraction of the 0.174 C per decade rate of heating that occurred 1917-1944 that it is pretty clear that CO2 had nothing to do with the warming of the first half of the last century. Even the IPCC climate modelers concede this point.
But there is still more to be learned from that period. Apparently some natural phenomenon allowed the earth to absorb energy at a significant rate and produce the temperature increase of the first half of the century. Let’s see how much that might have been. To begin, the earth would have had to take in enough heat to at least produce the additional surface radiation that would accompany a temperature rise of 0.174 C per decade 1917-1944. This would be (5.4 watt/m^2/C)x(0.174C/decade) = 0.94 watt/m^2 per decade. This is already 94X the CO2 heating rate.
But, in addition, as shown by both the ARGO buoy system and heat transfer calculations, at least 700 meters of upper ocean can respond to heating on a time scale of a decade. The additional amount of heat required to raise its temperature by 0.174 C per decade would be c*d*0.174C, where c= 4.3×106 joule/m^3/C is the heat capacity of sea water and d= 700 m, or 5.2×10^8 joule/m^2. Dividing by the number of seconds in 10 years, this would be an average of 1.7 watt/m^2 per decade. But since it would start at zero, it would have to end at 3.4 watt/m^2 per decade in order to attain this average. This should be added to the 0.94 watt/m^2 per decade surface radiation losses by the end of the warming period. So the total heating rate would have to ramp up by 4.3 watt/m^2 per decade to provide the warming that actually occurred in either of the rapid warming periods. This is 430 times the direct CO2 surface heating for 1917-1944.
Since essentially the same rate of temperature increase occurred 1976-2000, we can compare 4.3 watt/m^2 with the heating that might have been caused by CO2 in the last part of the last century. From 1944 to 2000, the CO2 concentration increased from 310 ppm to 370 ppm, with a doubling time of about 140 years. The corresponding climate forcing that would have caused, at the surface, would be (390/240)x(log(370/310)/log(2))x(2.7 watt/m^2)/14 decades = 0.08 watt/m^2 per decade.
Due to the higher rate of growth of CO2 concentration in the second half of the 20th century, this is 8X as large as the direct surface heating effect caused by CO2 in the first half. Nevertheless, it is still some 54 times smaller than the rate of heating that actually occurred.
These straightforward calculations make it painfully obvious that CO2 forcing is not what drove the two periods of rapid heating during the last century. Until there is some understanding of the natural causes of these rapid warming periods and their inclusion in the climate models, there is no reason to believe the models. This is simple first year physics.
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Stan Robertson, Ph.D, P.E, retired in 2004 after teaching physics at Southwestern Oklahoma State University for 14 years. In addition to teaching at three other universities over the years, he has maintained a consulting engineering practice for 30 years.
Martin Audley says:
March 25, 2013 at 5:25 am
As rgbatduke already said, the CO2 levels in the atmosphere are measured quite accurate. In my opinion even with the best and most rigourisely quality controlled network of the world for any known measurement. That shows that the CO2 levels are increasing significant, slightly exponential, over time since at least 1900.
One can discuss a lot of findings like the temperature record, where the quality control is often questionable or even absent. But CO2 measurements at individual baseline stations have an accuracy of 0.1 ppmv and between stations there is not more difference than +/- 2 ppmv for yearly averages. The main differences are because of a lag in the increase with altitude and latitude. The SH levels lag the NH with 1-2 years, which points to the NH as main source of the increase.
Here a comparison between temperature, human CO2 emissions and CO2 levels in the atmosphere over the period 1900-2006:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/temp_emiss_increase.jpg
Trashing the CO2 hypothesis without looking further a green field is not moving the science forward, and eventually it is simply a waste of time.
Robin Edwards says:
March 25, 2013 at 8:30 am
Where, then, does the oft quoted “exponential” character of the atmospheric CO2 concentration arise?
Indeed hardly visible in the curve, thus the exponent is very small, as Alan D. McIntyre calculated. It is better visible in the average year by year increase:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/dco2_em.jpg
From 0.8 ppmv/yr increase in 1960 to near 1.8 ppmv/yr in 2006 and 2.1 ppmv increase last year…
The rate of change of both human emissions and the increase in the atmosphere are increasing linearly which gives a slightly exponential increase of both the total emissions and the increase in the atmosphere. The remarkable effect is that increase in the atmosphere remains at a very stable ratio with the human emissions:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/acc_co2_1900_2004.jpg
Natural recovery from the Little Ice Age? Seems to me everyone is running around trying to find something on which to “blame” the recovery of the climate from one of the coldest periods in the Holocene.
Seems like Team science is so bad, that even when one uses their standards as defined, to demonstrate the divergence of results, others get bogged down in the shadow science of the IPCC.
As I understand Stan Robertson, even if one uses the IPCC’s assumptions and mathematics, their argument is F.U.B.A.R by reality.
I appreciate rgbatduke’s point we do not know and cannot say using the data we currently have.
However I am fed up with the corruption, wilful blindness and fraud, that is climatology.
The false certainty and lust for power that runs thro this perversion of science, has me gnashing my teeth and looking for a scapegoat to rend.Not a great place for a so called science.
And a very uncomfortable place for a man who wants to believe in civil society.
How did we sink so low as to create a religion over plant food?
Can you explain the appearance of frost with, say, an air temperature of 35 deg F?
.
Stephen Wilde says:
March 25, 2013 at 8:39 am “And I don’t see Ed_B’s comment as anthropomorphic as does rgbatduke.
All that happens is that the atmosphere obeys the Gas Laws as it must.”
Thanks. I agree. I was “feeling” the gas laws. Ha.. too long a mechanical engineer I guess.
Stephen, your descriptive models have helped me, along with Willis’s great analysis of the equatorial thunderhead storms doing vertical heat transport above most of the CO2, and also Bob Tisdales work on the earths natural horizontal ocean heat distributuion capability.
The earth is dynamic system, and I am stongly uncomfortable with the static approach describing anthroprogenic CO2 radiative forcing.
_Jim: it’s all about the atmospheric window. Of net IR from the Earth’s surface, 2/3 rds goes to space. At night this still happens so you go sub sero with a clear sky.
Air temperature 15 °C with all radiative heat transport requires a surface temperature of -13.5 °C.
Hence the cold surface is covered with dew or frost and triggers fog.
There is no GHG blanket – it’s a pathetic bit of physics by people who haven’t a clue about real heat transfer.
How come the difference between man caused C02 and natural C02 is hardly ever noted even on this site related to C02 and temperature levels. When the question is asked it seems to be ignored. For sake of argument lets go with the IPCC temperature rise of 3 degrees, C or F who cares. Lets say mans contribution to C02 level is 3%. Mans contribution to temperature rise is then .09 degree who cares.
I guess because there is virtually no difference except to someone’s bank account the .09 is conveniently ignored.
To me all the seemingly endless arguments, discussions, research, activists marches and so on just goes poof, if the above is enforced.
Please someone tell me what I am missing here?
It seems the is a sifi author by the name of Kim Stanley Robinson, who wrote a series of novels dealing with green issues, social justice and climate change. If this is our man, he’s had a major change of heart.
Just a shot in the dark.
http://www.kirkdorffer.com/ontheroadto2008/2007/05/kim-stanley-robinsons-science-in.shtml
vukcevic says:
March 25, 2013 at 9:28 am
What exactly is a “CO2 hypothesis” ??
I’ve said it before and I’ll say it again: the AGW hypothesis is easily and quickly disprovedn by simple observation and even simpler arithmetic.
Observation #1: Temperatures are lower today, 80 years later, than they were in the 1930s despite a 40 percent increase in atmospheric CO2 over that time. Likewise, at least three warm periods, all warmer than today and occurring at times of lolw CO2 concentrations, are well documented in the historical, as well as the physical record: the Hittite-Minoan-Mycenean period, 1800-1400 BC, the Roman Climate Optimum, 100 BC-300AD, and the Medieval Warm Period, 900-1300 AD.
Zero correlation between CO2 and temps for nearly 4,000 years – how much longer a record do we need? (And of course this doesn’t include the end of the last ice age 12,000 years ago, a quite observable length of time before the Industrial Revolution.)
Observation #2: One other, and not the largest other by far, source of CO2 emissions is animal respiration. From respiration rates and volumes and the known percentage of CO2 in exhaled human breath, by simple arithmetic, on average each person on the planet emits about 500 kg of CO2 per year. Extrapolating to the 7 billion of us on Earth, thast’s 3.5 gt per year. As numerous as we are, man is probably less that 1/2 percent of the animal biomass on the planet, and definitely is one of the lower emitters of CO2 on a per-pound of-body-weight basis. But if man is assumed to be an average emitter, this still translates by very simple arithmetic into 700 gt of CO2 from animal respiration. And in all probability that is an understatement, because at least half of the animal biomass is insects, with emission rates per pound of body weight up to 20 times that of humans. This versus 38 gt/yr of gross CO2 from fossil fuels and 10 gt residual, 48 hours after emission.
Observation #3: Water vapor (except in the relatively small areas of super-dry desert on Earth) constitutes anywhere from 30 to 140 times as much of the atmosphere as CO2, figured by simple arithmetic from the vapor pressure of water and the relative humidity. It has a specific heat about 4.5 times that of CO2 – which probably understates the actual coimparative effect of H2o vs. CO2 as a greenhouse gas. But going solely on specific heat, water vapor, by simple arithmetic, has between 135 and 630 times the effect on climate as CO2.nd again this may be a huge understatement.
It doesn’t take a climate scientist to figure these things out, only a reasonably knowledgeable layman who can read and do simple arithmetic. Put simply, man’s activities are an infinitesimal fraction of an infinitesimal factor in climate change, at least four sigmas below the realm of statistical relevance. – mathematically, one over infinity squared.
The alarmists could only get around these facts by destroying every physics and chemistry textbook, monograph and journal article ever published plus all the libraries containing the source documents for the historial record. I doubt that they could do that.
@nc – Hope my last post answered some questions for you.
Regarding exponential growth in CO2: Obtain the CO2 yearly numbers (http://woodfortrees.org/data/esrl-co2/compress:12 for yearly averages), and drop them into your favorite spreadsheet software. Add a third column which is the log (Ln) of the concentrations, plot it adding a linear trendline.
The log of an exponential is a straight line – the log of the CO2 data curves up faster than a straight line, the concentration increasing faster than exponentially. While the exponent is quite small, it is present, and from the log trend is increasing over time. Hence the forcing of CO2 is increasing just a tiny bit faster than linearly over time.
Let me begin by saying that I have been commenting here under the name “bones”, however, my real name is Stan Robertson. I am a retired physics prof, (Ph.D 1969, Oklahoma) having last worked at Southwestern Oklahoma State University. That should take care of the comment of grumpyoldmanatUK.
Before replying to others, I need to correct two minor errors and add a comment. First, the CO2 forcing effects that I calculated for both warming periods should have used the actual number of decades over which the CO2 changes took place, rather than the number of decades required for doubling at the time.
Second, when corrected, the rate of heating at the top of the atmosphere that would have been caused by CO2 would have been only 0.14 watt/m^2 per decade in the 1976-2000 period. This is a good deal less than the 0.25 watt/m^2 per 1.1 decade of the solar cycle at the top of the atmosphere. So dismissing solar effects is completely unwarranted.
Now for some others comments:
@Ed_B: I was only playing the “radiation is everything” game of the warmistas.
@Jimbo: Ethanol was originally used as an ozone reducing oxygenate in gasoline to replace MTBE, which was shown to be both carcinogenic and environmentally persistent.
@Alan D. McIntire: The 390/240 ratio is only to roughly account for the effect of the atmosphere lying between the surface and the top of the atmosphere.
@Greg Holmes: Amen! and thank you.
@Solomon Green: Beddington is wrong. Surface temperatures respond on a seasonal time scale. The thermal lag is no more than a decade. Thermal lag is the last refuge of warmists who don’t know physics and don’t understand why there has been no warming for the last 16 years.
@higley7, Robin Edwards and bobl: Check out this graph of Mauna Loa CO2 data and tell me again that 5% per decade isn’t exponential: http://i1244.photobucket.com/albums/gg580/stanrobertson/TW-co2-t.jpg
@Robin Potter: See my (above) comparison of solar cycle heating with CO2 at the top of
atmosphere.
@rgbatduke: Thank you for your summary! I have enjoyed the things that you post at WUWT.
@Gail Combs and Joe: Thanks for explaining what I was doing!
@Bob Tisdale: I sincerely apologize for using your graph without attribution. I have pilfered hundreds of graphics for my own use over the years and I honestly could not remember where I had gotten it. But that was a glaring lapse on my part not to have taken the time to find it. I have enjoyed reading your articles here on WUWT. They have been very informative!
@AlecM: What would be the average (over a year or two) earth temperature as viewed from space in cloudless regions and in the bands of the Atmospheric Window? And what would be the radiation rate in watts/m^2? Would not the average outbound radiation over the entire surface as measured at the surface be about the same?
Lastly, Thanks to the others who took the time to read this.
@NC, I agree with you. But it’s even worse because extra CO2 will cause a rise in temperature of exactly 0C! .. nothing, nodda, zilch. All of this conversation is simply mental masturbation, and getting very old.
BTW, belated congrats to Anthony and crew on a marvelous achievement by winning a smashing 3rd Blog award! … that is awesome!
Wildly and completely incorrect. These are not even remotely factual statements. As has been proven and re-proven here many times over.
It currently takes 1 BTU of energy in (be it gasoline, oil, ethanol or other), plus the stored solar value in the feedstock, to create a current average of between 1.6 and 2 units of energy out in the form of ethanol. This is for standard corn ethanol processes. Newer processes including cellulosic biomass are much higher yet.
On being a greenhouse gas emissions loser, another outright false statement. Ethanol use directly reduces greenhouse gas emissions significantly over the use of fossil fuels. The author ADMITS ethanol is cleaner burning and has other environmental benefits. It is a low carbon fuel source and reduces use of fossil fuels – a double benefit to the environment. Whether you CARE about CO2 or not, there is no valid reason not to minimize its production where reasonably possible. AND most importantly ethanol is RENEWABLE,
The ONLY way to make this ridiculous and wholly unsupported claim – that ethanol increases greenhouse gas emissions, is to make the unproven and unsupported claim that growing corn in the Midwest increases corn prices and causes massive reduction in rain forests as they cut them down to plant corn.
Despite a large increase in corn production, and rising prices for many years now – both beginning well before wide use of ethanol – there has been no supportable evidence of this claim. And scientists agree. More than 100 scientists researching biofuel production agree, calling theses claims misguided and based on limited scientific models. “Results from the model have not been verified enough to be useful,” said Harvey Blanch, a professor of biochemical engineering at University California, Berkeley.
http://www.scientificamerican.com/article.cfm?id=biofuel-crops-could-also-cleanse-soil
The facts are that US corn is in most cases far cheaper than locally grown corn. This is exactly the problem in Guatemala – which was held up as one of the poster children for the big, bad ‘ol US corn ethanol industry. Unfortunately for those claims, when one actually bothers to research, rather than blindly repeat partisan talking points, you find Guatemalans could grow plenty of corn. Which they used to do, until imported US corn became so cheap it made more sense to import our cheap corn and grow more profitable crops on their land. Today, Guatemala continues to buy US corn, increasing the amount the ALLOW to be imported, because it is far cheaper than their own, in order to hold DOWN local prices. Oh, and the US has provided ALL the corn Guatemala has asked for.
These oft repeated claims are ignorant in yet another way as well. People in places like Mexico, Guatemala, and other corn consuming regions do not generally eat yellow corn. They eat White Corn – which the US is also a large exporter of. We grow enough white corn to meet our domestic needs and all export demand. It should be noted as well white corn production in the US is a tiny fraction of overall corn output.
When someone makes such easily refuted, incorrect, unsupported and outright specious claims in the opening comments, its hard to take the rest of the article seriously.
Stan Robertson, the author, writes:
“Until there is some understanding of the natural causes of these rapid warming periods and their inclusion in the climate models, there is no reason to believe the models. This is simple first year physics.”
There seems to be a tidal movement to embrace “natural variability” and “natural regularities” among once faithful Alarmists. I believe that Beddington appealed to natural variability as an explanation of the last fifteen years of flat temperatures. Recognition of natural variability is a huge step for Alarmists. It was less than two years ago that Trenberth called for a reversal of the null hypothesis – the hypothesis that natural variability explains temperature variation since the Little Ice Age.
Of course Beddington appeals to natural variability in a self-serving way, as an excuse for the modelers, but genuine scientists are publishing articles that attribute most of the twentieth century rise in temperature to natural regularities that are not yet well understood. The future might hold less stonewalling among Alarmists and a greater openness to empirical science.
Let’s just cut to the chase:
1-Science gave us pesticides and while science does agree
it’s real “and happening” they don’t agree climate change will be a
real crisis, only that it’s real. I know, strange but true look it up.
2-Science has only said climate change “COULD” be
a crisis and never said it will be. Look it up.
3-Science says comet hits are a real eventual crisis but not
climate change crisis. Look it up.
4-Not one IPCC warning is without “maybe” and
“could be” and….Look it up.
5-27 years of a maybe crisis means it won’t be a crisis.
REAL planet lovers and REAL “progressives” don’t childishly
enjoy loving a planet with fear.
“Thus while CO2 concentration is increasing exponentially with time, the temperature only increases linearly.”
Over the past 20 years, CO2 concentration is increasing linearly, or close enough to it to make little difference:
http://woodfortrees.org/plot/esrl-co2/from:1993/to:2013/plot/esrl-co2/from:1993/to:2013/trend
You can see that any deviation from a constant linear trend is minuscule. There’s a very slight bend in the curve just post Pinatubo (3 or 4 years), otherwise it’s flat as a die at roughly 1.9 ppm/year.
nc says:
March 25, 2013 at 10:36 am
Please someone tell me what I am missing here?
What you are missing is that the 3% human is additional, the 97% natural is mostly back and forth cycling.
Humans add about 3% of the total CO2 input, but don’t contribute to the CO2 output over a year. Thus while 97% of the input is natural, 98.5% of the total input is absorbed by natural sinks. Slightly more sink than source for all natural processes together. The residual 1.5% is what you see as increase in the atmosphere.
It doesn’t make any difference if the natural cycle is 10 times or 100 or 1000 times the human input. As long as the natural inputs are less than the natural outputs, the contribution of nature to the increase is zero and all increase (in total quantity, not in original molecules) is human made.
Think of a factory where you invest each year some money. The turnover of the factory may be huge, 100 times what you invested within a year, but if you see that the factory at the end of the year, every year for the past 50 years or so, shows less profit than what you have invested, it may be wise to look for a better investment…
jorgekafkazar says:
March 25, 2013 at 12:00 pm
See the difference if you plot the CO2 levels from 1960 on:
http://woodfortrees.org/plot/esrl-co2/from:1960/to:2013/plot/esrl-co2/from:1960/to:2013/trend
Am I correct in noting the following?
* The IPCC was founded in 1988.
* The IPCC published its first assessment report in 1990.
* The Atlantic Multidecadal Oscillation (AMO) was discovered in 1994.
* The Pacific (inter-) Decadal Oscillation was noticed in 1997.
A. Scott says:
March 25, 2013 at 11:49 am
“Results from the model have not been verified enough to be useful,” said Harvey Blanch, a professor of biochemical engineering at University California, Berkeley.
—————————————————————————————————————-
Funnily enough, exatly the same situation we have with all those climate models which that pesky Mother Nature keeps declining to verify.
One model verifying another doesn’t count if they both miss reality btw 😉
I understand the desire to “use their rules” to show their claim is not supported by “their facts”; but at least a tiny mention of convection and enthalpy (i.e. evaporation and precipitation) acting as a heat pipe taking heat from the surface to the top of the troposphere (kind of the definition of it, not radiative, convective) would have been nice.
The whole void at the center of the AGW thesis is the ignoring of non-radiative physics.
http://chiefio.wordpress.com/2012/12/12/tropopause-rules/
BTW, folks tend to think of the tropopause as a static lid on the troposphere were radiation has to carry the heat across the barrier. That is “exactly wrong”. There is significant mixing and air flow across it. In reality, it is a Cat 2 hurricane force wind zone where the vertical air flow turns sideways and heads toward the cold pole of the planet (where it makes “Night Jets” and the polar vortex and descends, mixing with stratospheric air on the way). Hardly static.
See this graph of wind speed vs altitude and ask yourself if those wind speeds are static:
http://chiefio.wordpress.com/2012/12/12/tropopause-rules/wind-speed-alt-1090/
That spike in speed is the tropo“pause”…
But yes, showing them bogus with their own (broken) world view is a nice touch. Just not the real world…