Bishop Hill What New Scientist wouldn't print
Jun 3, 2016 Climate: sensitivity A couple of weeks back, New Scientist published an article trying to up the ante on climate sensitivity.
One headline-making 2013 study had concluded that the immediate warming that would result froma doubling of CO2 in the atmosphere would be around 1.3°C - significantly less than most previous estimates. But this was before global temperatures shot past 1°C above pre-industrial levels last year, as predicted by New Scientist in July 2015. If the 2013 study was repeated using that value, it would give an estimate for the immediate warming of 1.6°C, says Piers Forster...
It also claimed that Forster and Lewis's 2013 paper had got its estimates of aerosol forcing wrong:
[Other studies] suggested that Forster's team underestimated how much warming has been masked by the cooling effect of other pollutants, such as sulphur aerosols, that we pump out alongside CO2.
Quite why anyone would want to estimate TCR from a single year's temperature figure is anyone's guess. This observation prompted Nic Lewis to write a letter to the editor, which, needless to say, has not been published. So you can read it here.
Letter to the Editor concerning New Scientist article in the 28 May 2016 issue, Vol 230, No 3075, page 8: 'Earth's sensitive side'
The claim in your 28 May article 'Earth's sensitive side' that the strong warming over the last few years means we can now rule out low estimates of climate sensitivity is wrong. You quote Piers Forster, a co-author (along with myself) of one 2013 study that concluded near-term warming from a doubling of CO2 in the atmosphere would only be around 1.3°C. I have also been sole or lead author of three different studies published since then, all of which support that conclusion. One of those studies used the Intergovernmental Panel on Climate Change 2014 assessment report's estimates for the effects on the Earth's radiation balance of both warming agents such as CO2 and of cooling agents such as sulphur aerosols. I have extended these estimates to 2015 and recomputed the warming from a doubling of CO2. It is unchanged at 1.3 °C, averaging over 1995-2015 data. It remains 1.3 °C when using data just for the last ten, or five, years. Use of a shorter period gives a less reliable estimate; using a single year's temperature is unsound.
The suggestion that the team Forster and I were part of underestimated how much warming had been masked by the cooling effects of sulphur aerosols and other pollutants is mistaken. Our team's method is unaffected by the arguments on this point raised by the Shindell and Schmidt team studies referred to. The latter study anyway contained several errors. The corrected version fixed two of the errors I had pointed out, and shows that near term warming from a doubling of CO2 is correctly estimated from the historical mix of warming and cooling agents, including sulphur aerosols. Moreover, the findings by the Storelvmo team relied on a relationship existing between solar radiation at the surface and sulphur emissions, but over their full data period that relationship is statistically insignificant. Furthermore, two recent studies (Stevens 2015 and Kirkby et al. 2016) conclude that sulphur aerosols have had less effect on radiation than previously thought, implying that estimates of the warming from a doubling of CO2 are actually too high.
Reader Comments (123)
Entropic man (Jun 7, 2016 at 11:52 PM and Jun 8, 2016 at 12:10 AM), it's clear that your fixation with CO2 is beyond reason and it's therefore futile to continue this discussion.
Hopefully, this thread stands as evidence to any third party who may wonder about the reasoning behind your views... to quote the great Burns:
O wad some Pow’r the giftie gie us
To see oursels as others see us!
It wad frae monie a blunder free us
An’ foolish notion
Entropic Man:
Assuming a net forcing of zero at 280 ppm, and 3.71 (units) at 560 ppm (1 doubling), a linear relationship (straight line graph) between forcing and CO2 concentration would result in 7.42 (units) at 840 ppm, and 11.13 (units) at 1120 ppm (2 doublings). At 2240 ppm (3 doublings) the forcing would be 25.97 (units). The gradient of the graph is 3.71 units per 280 ppm.
So, 3.71 (units) after 1 doubling, 11.13 (2), and 25.97 (3), not 3.71 (1), 7.42 (2) and 11.13 (3 doublings) as you say.
The relationship between forcing and CO2 concentration is actually logarithmic, not linear, which you imply by using a log function in your calculation in the first place. Of course there’s a linear relationship between the log function of CO2 concentration and forcing - that’s because it’s a logarithmic relationship after all.
Coming back to your back of envelope calculation, you’ve assumed a straight line relationship between temperature and CO2 concentration. The relationship is logarithmic not linear, therefore 1.85 C per doubling of CO2 is correct, using your data, not 2.2 C, your result assuming a linear relationship.
Jun 8, 2016 at 8:43 AM rotationalfinestructure said:-
".....1.85 C per doubling of CO2 is correct, using your data, not 2.2 C, your result assuming a linear relationship."
The calculations of the temperature response to a doubling of atmospheric concentration of CO2 , whether it be 1.85ºC or 2.2ºC assume that it is changes in CO2 concentration that cause changes the global average atmospheric temperature. Even if this were the case - which is clearly not unchallengeable - the case relies on the proposition that recent ( ie. over the last century and a half) increases in atmospheric CO2 concentration are largely , perhaps even exclusively, man made and that a reduction in anthropogenic emissions will reduce, halt, or even reverse the increase of CO2 concentration in the atmosphere with a consequent effect on the global average temperature.The published and peer reviewed literature does not unequivocally endorse this proposition however.
For example:-
Atmospheric CO2 concentration increased from 315.6 ppmv in 1958, to 359 ppmv in 1994. As these concentrations correspond to an atmospheric CO2 mass of 669 GtC and 761 GtC, respectively, the cumulative increase during 37 years was 92 GtC; that is, about 14 percent of the 1958 atmospheric mass of CO2. The average annual increase in this period was then about 2.5 GtC.
Each year about 12 percent of the total atmospheric mass of CO2 exchanges with the ocean, and about 13 percent with the land biota (IPCC 1990). It is possible that the observed CO2 increase is the result of a small change in this annual natural CO2 flux, caused by increased degassing from the warmer ocean, and increased oxidation processes at land and sea, resulting from natural climatic fluctuation. This possibility was not discussed in the IPCC document.
The IPCC estimated that the temperature of the surface waters increased between 1910 and 1988 by about 0.6°C. A similar increase was observed in the surface air temperature in this period. Increasing the average temperature of the surface of the oceanic waters (15°C) by 0.6°C, would decrease the solubility of CO2 in these waters (0.1970 g CO2 per 100 g) by about 2 percent. The CO2 flux from the ocean to the atmosphere should be increased by the same factor; that is, by about 1.9 GtC/year. This is similar to the observed average increase of atmospheric CO2 in the years 1958 to 1968, of 0.73 ppmv/ year, which corresponds to 1.6 GtC/year. The measured annual atmospheric CO2 increases were higher in the next two decades (2.5 GtC/year and 3.4 GtC/ year), which indicates that changes in CO2 solubility in oceanic water were responsible only for a part of observed CO2 increases.
Inorganic processes on land and changes in marine and terrestrial biota could also contribute to these increases. The atmospheric air and sea surface temperatures did not increase smoothly during this period, but were rather irregular, changing significantly from year to year. The annual changes in atmospheric CO2 mass closely followed the temperature changes. This was probably the result of rapid equilibration between CO2 concentration in the atmosphere, and the dissolved inorganic carbon in the sea in about three quarters of a year.
The greatest cooling and largest decreases in the rate of atmospheric CO2 increase occurred after volcanic eruptions which reached the stratosphere, characterized by high dust veil index: Gunung Agung in 1963, Fuego in 1974, El Chichon in 1982, Nevado del Ruiz in 1985, and Pinatubo in 1991.
On the other hand, the smoothly and steadily growing annual increases in anthropogenic emissions of CO2 from fossil fuel burning and cement production, do not match the atmospheric CO2 fluctuations. Since 1988, these sharply growing anthropogenic emissions have not been associated with decreasing values of d1 3C of atmospheric CO2; for 7 years between 1988 and 1994, this latter value remained remarkably stable. If the observed changes in CO2 concentration were man-made, a decrease in d13C should be observed.
During the famous “energy crisis” in 1974-1975, there was practically no decrease in anthropogenic CO2 emissions, but there was a dramatic drop in annual mass increase of atmospheric CO2 associated with atmospheric cooling; in 1983, the decreasing anthropogenic CO2 emission rate was associated with a peak in the rate of atmospheric CO2 mass increase, preceded by a cooler air temperature in 1982; in 1992, the highest rate of anthropogenic CO2 emission was associated with one of the deepest drops in atmospheric CO2 mass increase, and air cooling.
The data suggest that CO2 atmospheric mass increases were not entirely related to man-made emissions of this gas, but rather that these increases depended on volcanic eruptions and other causes of natural climatic fluctuations.
Thus even if the temperature response to CO2 concentration is the principal driver of atmospheric temperature it is not at all certain that even effective measures to reduce anthropogenic emissions will necessarily result in the postulated, and anticipated temperature response.
The Backfire Effect : The Misconception: When your beliefs are challenged with facts, you alter your opinions and incorporate the new information into your thinking.
The Truth: When your deepest convictions are challenged by contradictory evidence, your beliefs get stronger.
https://youarenotsosmart.com/2011/06/10/the-backfire-effect/
There is no winning of any argument against people with strong beliefs. The best you can hope for is to appear more logical than your opponent to any casual observer. In public debates of course, skeptics always win. Media and politics though seem to favour counting heads rather than counting failed predictions. The 'consensus' has 50+ alternative excuses for their predictive failures, most of which can be classified under 'natural variation' - of the same sort that was discounted 20 years ago. The only true consensus enviro-alarmists share is that fossil fuels must be bad somehow; whether cooling, warming, acidifying or whatever next......for reasons that seem to skeptics to lack a rational basis yet involve ignoring the world around them.
97% of Climate Scientists get very upset about the failed disaster of their ambitiously high levels of sensitivity.
Once you accept a simple mathematical equation can predict future planetary temperatures, you have not only lost the plot, you have lost the argument. Something like 97% of mortgage holders, car loan payers and child rearers will disagree with your calculations.
One of the most used words in these debates is 'estimate' and that's what it really comes down to. Judgement and/or bias and/or article of faith. I blame John Cook for the proliferation of mathematically simplistic, tabloid idiocy. A born again Christian with a strong predilection for Matthew 25 (Judgement Day).
http://www.theguardian.com/environment/blog/2010/aug/25/solar-physicist-religion
esmiff, if it wasn't for John Cook's publicity funding, the world would not know that 97% of climate scientists are wrong.
97% of Climate Scientists have not corrected the failed cartoonist, which could be Cook's only successful joke.
Jun 6, 2016 at 11:13 PM | Unregistered CommenterEntropic man
Simple question for EM on cloud feedbacks
"Increased low altitude cloud increases albedo and has a cooling effect. Increased high cloud decreases radiation to space and has a warming effect. The combined effect is neutral."
If the Earth today became permanently 100% covered by high cloud would the Earth warm or cool?
JamesG (Jun 8, 2016 at 10:33 AM), your comment is rather apt and very much appreciated.
I hear that logarithms are to be renamed "denierithms" because 97% of "climate scientists" don't know how to calculate using logarithms.
Jun 7, 2016 at 8:30 AM | Unregistered Commenterrotationalfinestructure
Well, although the Holy Climate Formula is the cornerstone of CAGW belief and is quoted as if it were something established beyond question, it is certainly used by believers who are sometimes a bit shaky on the basics of logarithms.
From the archives:
97% of climate scientists need to learn sums on a zero salary contract, our grandchildren will all be grateful.
@Paleoclimate Buff
Where do I say the CO2 is all anthropogenic?
The fact that "Entropic Man" has overestimated the calculated effect of doubling CO2 to 560 ppm, by MORE THAN FORTY PERCENT, by his failure to calculate a logarithmically dependent function, means that the actual origin of the increased CO2 hardly matters. CO2 is far less of a problem than he estimates.
@Alan Kendall (Jun 7, 2016 at 7:16 AM)
As your example illustrates, while CO2 concentration is quite uniform around the world at approx. 400 ppm, atmospheric gaseous water concentration, i.e. humidity, varies enormously from day to day and place to place.
The climate sensitivity due to CO2 can be calculated straight forwardly, AIUI, from the Stefan Bolzmann equation, latency of molecular vibrational energy states, etc., at around 1 degree C per doubling of CO2.
How the water vapour feedback can triple climate sensitivity due to CO2 isn't explained.
When Entropic Man says the albedo effects of low and high level clouds are neutral, that's not something I find credible when he also claims a large water vapour feedback.
rotationalfinestructure
You did not assert that( the increase in) CO2 in the atmosphere is all anthropogenic nor did I impute that you did. Nor has Entropic man explicitly asserted it either. I merely point out that the CAGW case for restricting the use of fossil fuels relies on the assumption that the increase is largely, or even entirely, a result of anthropogenic CO2 emissions which may not be the case. The temperature response to increased CO2, whatever the numerical relationship is, of course, independent of the source of the CO2 emissions to the atmosphere.
Entropic man said:
"A 45% increase in CO2 has produced a transient climate response of 1C."
No, it hasn't. That's just you assuming it has. Where's your empirical evidence?
Kristian
How do you define "empirical evidence"?
Entropic man,
You claim, without hesitation or caveats, that "A 45% increase in CO2 has produced a transient climate response of 1C."
You clearly know something about this, then. That this is actually the case. Somehow an established truth. And you still have to ask me how I define "empirical evidence"!?
How do you know that CO2 has caused a 1 degree rise in global temperature over the last 135 years? What do you base such a claim on? Do you base it simply on your personal belief that it ought to have? Or do you have anything a bit more ... substantial?
Kristian ( How [does EM] know that [ a 45% increase in ] CO2 has caused a 1 degree rise in global temperature over the last 135 years? )
In 2000 the concentration of CO2 in the atmosphere was 371 ppm volume - equivalent to 565ppm mass. In 2014 it was 400 ppm volume equivalent to 609 ppm mass. These concentrations represent 2.904 x 1012 Tonnes of CO2 in 2000 and 3.135 x 1012 tonnes of CO2 in 2014 – an increase of 0.231 x 1012 or just under 8% of the total CO2 in the atmosphere in 2000 using the generally accepted figure for the mass of the atmosphere of 5148 x 10 15 tonnes.
The cumulative emissions of CO2, from 2000 to 2014 inclusive, total 0.467 x 10 12 tonnes so the increase in the CO2 content of the atmosphere is approximately 49.5% of the amount of anthropogenic emissions of CO2 during the same period. According to woodfortrees.org website the HADCRUT4 global mean temperature series shows no increase in GAT for the period 2000-2014.
In 1850, if one uses the generally quoted figure of 280 ppm volume for the “ pre-industrial” atmospheric CO2 concentration this represented 435ppm mass - equivalent to 2.236 x 10 12 tonnes of CO2 in the atmosphere. The increase between 1850 and 2000 is 0.668 x 1012 tonnes and is equal to a 23% increase in the mass of atmospheric CO2 . HADCRUT4 shows a temperature rise of almost exactly 1ºC for an increase in CO2 concentration during the same period.
On this basis a further increase of 0.231 x 1012 tonnes between 2000 and 2014 should have resulted in a temperature increase of about 0.35ºC - in a period when the HADCRUT 4 series shows no increase at all. And this is not the only period since 1850 when temperatures have not risen, or indeed have actually fallen in at least on part of the period, while anthropogenic emissions and the atmospheric mass of CO2 have both increased - which raises the issue of whether the concept of “Climate sensitivity” to CO2 is soundly based theoretically or even useful ( other than for political effect).
Spectator
You are assuming that the increase in CO2 is the only factor affecting themperature. Over the 135 year record this is correct because the net change due to other factors(albedo, volcanoes, , ENSO, solar cycles etc) is close to zero.
On a decadal scale these factors change enough at random to add short term noise to the long term CO2 signal.
Look at GISTEMP. Since 1970 the long term trend has been 0.18C/decade, due almost entirely to CO2.
The red line shows the post-1970 trend. The lines parallel to it show the noise level. You can also see larger spikes above the line due to El Ninos.
The 2000 to 2014 period you mentioned is too short to make judgements about CO2. The variation you discuss is within the normal range due to short term noise.
This graph also includes the post 1998 warming trend. It is notable that the "no warming since 1998" meme had become invalid as the post-1970 and post-1998 trends are now almost identical.
Kristian
I've already been over this ground earlier in the thread with David Salt. I see no point in repeating myself. Go back and read my June 5th, June 6th and June 7th posts.
EM says:-
a].... you [ Spectator)] are assuming that the increase in CO2 is the only factor affecting the temperature. Over the 135 year record this is correct because the net change due to other factors (albedo, volcanoes, ENSO, solar cycles etc) is close to zero.
and
b]Since 1970 the long term trend has been 0.18C/decade, due almost entirely to CO2.
I am sure most readers of this blog would really appreciate if Entropic Man could share with them the evidence on which he relies in support of these statements which even the IPCC not
Entropic man,
You seem to have the memory of a guppy. Or, a more likely explanation to your behaviour: Yours is a highly selective one ...
You appear completely oblivious to the real circumstances concerning the radiative imbalance at the ToA, even though you were only recently provided with real-world data detailing them.
1) The AGW hypothesis does not propose an observable radiative imbalance at the ToA, because it specifically states that OLR shouldn't be observed to decrease (and certainly not increase) during warming. In fact, that's the postulated "enhanced greenhouse" warming mechanism right there: Z_e goes up while T_e remains unchanged, which leads to a rise in T_s:
http://www.climatetheory.net/wp-content/uploads/2012/05/greenhouse-effect-held-soden-2000.png
2) OLR hasn't been observed to go down, and it hasn't been observed to stay flat during warming either. It has specifically been observed to stay flat during periods of no tropospheric warming (2000 >; CERES, HIRS) and to go up during periods of tropospheric warming (1985-1999; ERBS, ISCCP FD, HIRS). Which suggests very clearly that OLR at the ToA is simply a radiative effect of, primarily, tropospheric temps, and in no way a cause of temperature change over time.
The cause of the imbalance, hence of the resulting temperature change (and the concurrent accumulation of energy in the Earth system) observed since the 80s is evidently an increase in solar input, in ASR (TSI minus global albedo), which occurred between the 80s and the late 90s. The rise in OLR is simply a temperature response to this increase in solar input:
https://okulaer.files.wordpress.com/2016/05/toa-sw-refl.png
https://okulaer.files.wordpress.com/2016/05/toa-lw.png
https://okulaer.files.wordpress.com/2016/05/toa-net.png
Entropic man,
You seem to have the memory of a guppy. Or, a more likely explanation to your behaviour: Yours is a highly selective one ...
You appear completely oblivious to the real circumstances concerning the radiative imbalance at the ToA, even though you were only recently provided with real-world data detailing them.
1) The AGW hypothesis does not propose an observable radiative imbalance at the ToA, because it specifically states that OLR shouldn't be observed to decrease (and certainly not increase) during warming. In fact, that's the postulated "enhanced greenhouse" warming mechanism right there: Z_e goes up while T_e remains unchanged, which leads to a rise in T_s:
http://www.climatetheory.net/wp-content/uploads/2012/05/greenhouse-effect-held-soden-2000.png
2) OLR hasn't been observed to go down, and it hasn't been observed to stay flat during warming either. It has specifically been observed to stay flat during periods of no tropospheric warming (2000 >; CERES, HIRS) and to go up during periods of tropospheric warming (1985-1999; ERBS, ISCCP FD, HIRS). Which suggests very clearly that OLR at the ToA is simply a radiative effect of, primarily, tropospheric temps, and in no way a cause of temperature change over time.
The cause of the imbalance, hence of the resulting temperature change (and the concurrent accumulation of energy in the Earth system) observed since the 80s is evidently an increase in solar input, in ASR (TSI minus global albedo), which occurred between the 80s and the late 90s. The rise in OLR is simply a temperature response to this increase in solar input:
https://okulaer.files.wordpress.com/2016/03/toafluxesfdvserbs_zps3489ddec.png
Associate Professor in the School of Environmental Science at Auckland University, Chris de Freitas, has an opinion piece in this morning's NZ Herald, headlined No place for scare tactics. De Freitas refutes sociologist Jarrod Gilbert's opinion that "climate change denial" is a crime. http://www.nzherald.co.nz/opinion/news/article.cfm?c_id=466&objectid=11682506