By WUWT Regular “Just The Facts”:
Note: This article builds upon a previous article, When Did Global Warming Begin?, which offers highly recommended background for this article.
There appears to be some confusion as to when humans might have begun to influence “Earth’s Temperature”. For example, “Global warming is the unusually rapid increase in Earth’s average surface temperature over the past century primarily due to the greenhouse gases released as people burn fossil fuels.” NASA Earth Observatory “Ninety-seven percent of climate scientists agree that climate-warming trends over the past century are very likely due to human activities, and most of the leading scientific organizations worldwide have issued public statements endorsing this position.”
NASA Climate Consensus page “‘Global warming started over 100 years ago‘: New temperature comparisons using ocean-going robots suggest climate change began much earlier than previously thought”. The Daily Mail “The temperature, they pointed out, had fallen for much longer periods twice in the past century or so, in 1880-1910 and again in 1945-75 (see chart), even though the general trend was up. Variability is part of the climate system and a 15-year hiatus, they suggested, was not worth getting excited about.” Economist “Our Earth is warming. Earth’s average temperature has risen by 1.4°F over the past century, and is projected to rise another 2 to 11.5°F over the next hundred years.” EPA
However, there is not compelling evidence that anthropogenic CO2 was sufficient to influence Earth’s temperatures prior to 1950, i.e. “Climate model simulations that consider only natural solar variability and volcanic aerosols since 1750—omitting observed increases in greenhouse gases—are able to fit the observations of global temperatures only up until about 1950.” NASA Earth Observatory “The observed global warming of the past century occurred primarily in two distinct 20 year periods, from 1925 to 1944 and from 1978 to the present. While the latter warming is often attributed to a human-induced increase of greenhouse gases, causes of the earlier warming are less clear since this period precedes the time of strongest increases in human-induced greenhouse gas (radiative) forcing.” NASA Geophysical Fluid Dynamics Laboratory / Delworth et al., 2000 “Internal climate variability is primarily responsible for the early 20th century warming from 1904 to 1944 and the subsequent cooling from 1944 to 1976.” Scripps / Ring et al., 2012: “There exist reasonable explanations, which are consistent with natural forcing contributing significantly to the warming from 1850 to 1950”. EPA
So how to clear up this confusion? Let’s take a look at the data…
If you look at Global CO2 Emissions from Fossil-Fuels;
Global CO2 from Fossil-Fuel Emissions By Source;
and Cumulative Anthropogenic CO2 Emissions from Fossil-Fuels,
you can see that Anthropogenic CO2 Emissions from Fossil-Fuels did not become potentially consequential factor until approximately 1950, and then grew rapidly thereafter. Per the Economist, “The world added roughly 100 billion tonnes of carbon to the atmosphere between 2000 and 2010. That is about a quarter of all the CO₂ put there by humanity since 1750. And yet, as James Hansen, the head of NASA’s Goddard Institute for Space Studies, observes, ‘the five-year mean global temperature has been flat for a decade.’” The large increase in Anthropogenic CO2 Emissions from Fossil-Fuels since 1950 is quite clear in this Global Per Capita Carbon Emissions graph:
There have also been claims made that Land Use Changes measured as Annual Net Flux of Carbon to the Atmosphere were a significant source of Anthropogenic CO2 i.e.:
However, when you look at the Net Flux of Carbon to the Atmosphere from Land-Use Changes from 1850 to 1990;
it is apparent that the majority of the increase occurred after 1950, and the change between 1900 and 1950 was de minimis. Furthermore, the Houghton data these graphs are based upon is highly suspect, i.e. from IPCC AR4: “Although the two recent satellite-based estimates point to a smaller source than that of Houghton (2003a), it is premature to say that Houghton’s numbers are overestimated.” Houghton’s method of reconstructing Land-Use Based Net Flux of Carbon appears arbitrary and susceptible to bias; i.e. “Rates of land-use change, including clearing for agriculture and harvest of wood, were reconstructed from statistical and historic documents for 9 world regions and used, along with the per ha [hectare] changes in vegetation and soil that result from land management, to calculate the annual flux of carbon between land and atmosphere.” Furthermore Houghton’s findings have varied significantly over time, i.e. in Houghton & Hackler, 2001 they found that, “The estimated global total net flux of carbon from changes in land use increased from 397 Tg of carbon in 1850 to 2187 Tg or 2.2 Pg of carbon in 1989 and then decreased slightly to 2103 Tg or 2.1 Pg of carbon in 1990“. However, by Houghton, R.A. 2008 he found, “The estimated global total net flux of carbon from changes in land use increased from 500.6 Tg C in 1850 to a maximum of 1712.5 Tg C in 1991“.
Given Houghton’s overestimations, arbitrary reconstruction method and highly variable results, his Net Flux of Carbon to the Atmosphere from Land-Use Change data is not credible. However, even if it was, Net Flux of Carbon to the Atmosphere from Land-Use Change was inconsequential prior to 1950;
and it appears that Land and Ocean Sinks would have absorbed any increace, along with much of the minimal pre-1950 Anthropogenic CO2 Emissions from Fossil-Fuels. This is supported by the findings of Canadell et al., 2007 that, “Of the average 9.1 PgC y −1 of total anthropogenic emissions (F Foss + F LUC) from 2000 to 2006, the AF was 0.45; almost half of the anthropogenic emissions remained in the atmosphere, and the rest were absorbed by land and ocean sinks.” Furthermore, they found “increasing evidence (P = 0.89) for a long-term (50-year) increase in the airborne fraction (AF) of CO2 emissions, implying a decline in the efficiency of CO2 sinks on land and oceans in absorbing anthropogenic emissions.” Thus absorption rates of Land and Ocean Sinks were likely significantly higher prior to 1950.
As such, since there is not compelling evidence that Anthropogenic CO2 was sufficient to have ab influence Earth’s temperatures prior to 1950, Anthropogenic CO2 cannot be the cause of the warming that occurred before 1950. However, this doesn’t mean that CO2 based Anthropogenic Global Warming began in 1950, because if you look at the Met Office – Hadley Center HadCRUT4 Global Surface Temperature record for the last 163 years you can see that temperatures didn’t warm during the 1950s, nor the 60s:
In fact it was not until approximately 1975 that temperatures began to rise. However, this doesn’t mean that CO2 based Anthropogenic Global Warming began in 1975, because as Phil Jones noted during a 2010 BBC interview, “As for the two periods 1910-40 and 1975-1998 the warming rates are not statistically significantly different.” As such, the warming from 1910 – 1940, before Anthropogenic CO2 became potentially consequential, is “not statistically significantly different” from the warming during the period from 1975 – 1998 when the IPCC AR5 claims to be ” extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century”. Given that “causes of the earlier warming are less clear“, our understanding of Earth’s climate system is rudimentary at best, and our historical record is laughably brief, it is confounding how the IPCC can be so “extremely” sure “that human influence has been the dominant cause of the observed warming since the mid-20th century”, which is “not statistically significantly different” from the natural warming that occurred between 1910 – 1940.
Regardless, claims that “Global warming is the unusually rapid increase in Earth’s average surface temperature over the past century” are erroneous and indicative of either ignorance or duplicity on the part of NASA’s Earth Observatory, NASA’s Climate Consensus page, The Daily Mail, the EPA and many others. So what do you think? When Did Anthropogenic Global Warming Begin?
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drumphil says: March 31, 2014 at 9:20 pm
So, I went and read your article and the comments, and thought “no, you wouldn’t know those specific things from what was said.”
Why did you suppose that I posted this comment on “The Bucket Model”;
http://wattsupwiththat.com/2014/03/29/when-did-anthropogenic-global-warming-begin/#comment-1601090
wrote, “This is readily explained by the highly suspect Bucket Model adjustments Phil Jones and company made on the pre-1950 Sea Surface Temperatures i.e.:
http://wattsupwiththat.com/tag/the-bucket-model/
and then questioned Mosher here;
http://wattsupwiththat.com/2014/03/29/when-did-anthropogenic-global-warming-begin/#comment-1601133
on “Given the large and suspect adjustments that Hadley makes to the ICOADS data to create HadSST, do you know why BEST used the HadSST data set, versus applying its own processing to unadjusted ICOADS source SST data?”
There would be no need for further explanation if you had explained sufficiently to be sure that you weren’t just saying there were weakness in certain records, but were rather saying that the records were totally useless.
I never said they’re totally useless, in fact I used them in this article to demonstrate that;
“claims that “Global warming is the unusually rapid increase in Earth’s average surface temperature over the past century” are erroneous and indicative of either ignorance or duplicity on the part of NASA’s Earth Observatory, NASA’s Climate Consensus page, The Daily Mail, the EPA and many others.”
What I wrote was “I have zero confidence in our ability to accurately measure / estimate Earth’s temperature, CO2 concentrations and Anthropogenic contributions to CO2 prior to 1950”. The point is that the whole basis of the flimsy CAGW narrative is 1950 to present, because their is no evidence of a consequential anthropogenic contribution to CO2 prior to 1950 and the data prior to 1950 is highly suspect.
It is not reasonable to expect someone else to have inferred that from your statements without further guidance as to exactly what you think those things mean.
I disagree, and would guess that the majority of readers inferred that I had no confidence in the temperature data based upon the fact that I referred to it as highly suspect and questioned its use by BEST. However, I understand that you and MarkB did not, thus why there are comments, so you can ask questions and I can answer them.
I would like to ask a question, I wonder if any of you can answer it for me.
If man-made CO2 is such a driving factor, why is there no ‘bump’ in any of the charts during World War II? Compared to the 1930’s Great Depression, there was a huge increase in industrial activity in producing all the materials used in the war, as well as all the fuel burned in all the trucks, ships, airplanes, etc, and also the CO2 produced by all the burned cities.
It just seems to em that all this SHOULD have produced SOMETHING in the CO2 charts, and if CO2 is such a driver of temperatures, a bump in the temperature charts.
For every reaction there is a cause. The past ice ages were all caused by something very specific, right? It wasn’t just chance!
And so the Arctic ice Cap has shrunk dramatically in summer over the past decase. and the cause is WHAT?
1 photoshop
2. The sun got brighter!
3.orbital anomaly
4. volcanoes
5 God did it
6. Crap happens
7. 24/7 man made soot
8. Statisticspinning!
I say 7. Just IMAGINE if that were true-.the Earth’s thermostat melted thanks to us
Large chunks of the Arctic ocean now absorb 90% of sunlight instead of reflecting it in summer.That is 900 % increase for those square miles affected. I would call that an expotential increase as opposed to a linear one.
And common sense and high school physics dictate that the extra latent heat in the system has to manifest itself somewhere, and I say it does in the form of the weather anomaly pendulum swinging ever wider.
Man now puts out as much CO2 as all the volcanoes on Earth combined. Common sense and high school physics dictates that that has to have SOME kind of effect on our atmosphere!
DId you know that scientists once proposed that if we ever started slipping back into an ice age,all we had to do was take a bunch of planes and have them spread black soot on the Arctic Ice Cap to melt it!
Well guess what? We DID spread a whole bunch of soot on it via the many tens of thousands of commercial aircraft flights into the stratosphere each day, where it finds its way to the polar zone just like freon did in days of yore. 24/7 as opposed to occasionally the way Mother Nature USED to do it. And guess what else? it DID melt- well the average annual melt rate accelerated anyway
Where?
How?
When?
What latitude?
What day-of-year?
Show me the math – You are dead wrong.
I will repeat – under today’s conditions of minimum Arctic sea ice extents from late August until early April every year, open Arctic ocean water loses more heat energy via increased evaporation, conduction, convective, and radiation losses than is gained from the little bit of solar energy that is absorbed by the open water.
And your opinion is wrong.
It does! Trees, plants, plankton, algae and very living thing on earth are growing faster, stronger, and higher and more productively than ever before! Food, fodder, fuel, and farming ALL benefit from the increased CO2 … Or did yo fail to read your high school biology books as well?
David Costa, mmm, it’s volcanic dust that melts snow and glaciers, but only for a short time, as was demonstrated why Ortzi the ice man suddenly appeared after 5,000 years. But that was caused by dust settling on parts of the European Alps that absorbed light and sunlight warmth.
It was a rare event. And it soon froze up again when the melt subsided.
David Cossa says: April 1, 2014 at 2:50 pm
And so the Arctic ice Cap has shrunk dramatically in summer over the past decase. and the cause is WHAT?
1 photoshop
2. The sun got brighter!
3.orbital anomaly
4. volcanoes
5 God did it
6. Crap happens
7. 24/7 man made soot
8. Statisticspinning!
I say 7. Just IMAGINE if that were true-.the Earth’s thermostat melted thanks to us
There is ample evidence that the recent decline in Arctic Sea Ice is primarily driven by Wind and Atmospheric Oscillations, i.e.:
http://wattsupwiththat.com/2012/06/16/the-economist-provides-readers-with-erroneous-information-about-arctic-sea-ice/
Per this 2004 Science Daily article, ”Winds, Ice Motion Root Cause Of Decline In Sea Ice, Not Warmer Temperatures” states that,
“extreme changes in the Arctic Oscillation in the early 1990s — and not warmer temperatures of recent years — are largely responsible for declines in how much sea ice covers the Arctic Ocean, with near record lows having been observed during the last three years, University of Washington researchers say.”
And this 2007 NASA article “NASA Examines Arctic Sea Ice Changes Leading to Record Low in 2007“;
“Son V. Nghiem of NASA’s Jet Propulsion Laboratory, said that “the rapid decline in winter perennial ice the past two years was caused by unusual winds. “Unusual atmospheric conditions set up wind patterns that compressed the sea ice, loaded it into the Transpolar Drift Stream and then sped its flow out of the Arctic,” he said. When that sea ice reached lower latitudes, it rapidly melted in the warmer waters.”
“The winds causing this trend in ice reduction were set up by an unusual pattern of atmospheric pressure that began at the beginning of this century,” Nghiem said.”
justthefactswuwt says:
April 1, 2014 at 4:54 am
. . . The point is that the whole basis of the flimsy CAGW narrative is 1950 to present, because their is no evidence of a consequential anthropogenic contribution to CO2 prior to 1950 and the data prior to 1950 is highly suspect. . . .
There’s the 13C/12C carbon isotope ratios from tree rings and high resolution ice cores that show a clear downward trend starting early in the 19th century consistent with the rise in atmospheric CO2 starting about the same time which some consider indicative of an anthropogenic contribution by that time period. Not sure if that’s on your “highly suspect” data list or not.
MarkB says: April 1, 2014 at 7:35 pm
Wei et al. – Click the pic to view[/caption]
There’s the 13C/12C carbon isotope ratios from tree rings and high resolution ice cores that show a clear downward trend starting early in the 19th century consistent with the rise in atmospheric CO2 starting about the same time which some consider indicative of an anthropogenic contribution by that time period. Not sure if that’s on your “highly suspect” data list or not.
Yes, highly suspect. Roy Spencer assessed C13/C12 Isotope ratios back in 2008;
http://wattsupwiththat.com/2008/01/28/spencer-pt2-more-co2-peculiarities-the-c13c12-isotope-ratio/
and found that:
“Now, as we burn fossil fuels, the ratio of C13 to C12 is going down. From what I can find digging around on the Internet, some people think this is the signature of anthropogenic emissions. But if you examine the above equation, you will see that the C13 index that is reported can go down not only from decreasing C13 content, but also from an increasing C12 content (the other 98.9% of the CO2).
If we convert the data in Fig. 1 into C13 content, we find that the C13 content of the atmosphere is increasing (Fig. 2).”
“Note the strong similarity – the C13 variations very closely follow the C12 variations, which again (as in my previous post) are related to SST variations (e.g. the strong signal during the 1997-98 El Nino event).”
“BOTTOM LINE: If the C13/C12 relationship during NATURAL inter-annual variability is the same as that found for the trends, how can people claim that the trend signal is MANMADE??”
In support of Roy’s assessment, here’s Wei et al., 2009:
http://www.sciencedirect.com/science/article/pii/S0016703709000969
They analyzed “an ∼200 year δ11B isotopic record, extracted from a long-lived Porites coral from the central Great Barrier Reef of Australia. This record covering the period from 1800 to 2004 was sampled at yearly increments from 1940 to the present and 5-year increments prior to 1940. The δ11B isotopic compositions reflect variations in seawater pH, and the δ13C changes in the carbon composition of surface water due to fossil fuel burning over this period.”
They found that “In the periods around 1940 and 1998 there are also rapid oscillations in δ11B compositions equivalent changes in pH of almost 0.5 U.”
This does not appear to be indicative of anthropogenic influences, but rather natural Sea Surface Temperature variations.
Regardless, they found that “Correlations of δ11B with δ13C during this interval indicate that the increasing trend towards ocean acidification over the past 60 years in this region is the result of enhanced dissolution of CO2 in surface waters from the rapidly increasing levels of atmospheric CO2, mainly from fossil fuel burning.”
Here’s their Figure 1:
[caption id="" align="alignnone" width="581"]
As such, assigning anthropogenic causation to C13/C12 Isotope ratios is highly suspect, and furthermore Wei et al. only found increasing trends “over the past 60 years”.
I’m not clear why you think Wei etal supports Spencer’s hypothesis. It’s similar data to that presented by Ferdinand Engelbeen in the comments to the Spencer thread, (better summarized on his blog: http://www.ferdinand-engelbeen.be/klimaat/co2_measurements.html#The_13C12C_ratio ). I won’t rehash what was written there, but if the carbon isotope ratio in the upper ocean closely tracks the atmospheric trend, which the coral data suggests is the case, then Spencer’s premise is flawed. Short term atmospheric CO2 variation due to ocean out gassing would be expected to have the same signature as the atmosphere. Coral data aside, this is consistent with carbon cycle models in that the upper ocean exchange rate is high.
As for “Wei et al. only found increasing trends ‘over the past 60 years'”, I read that as an “acceleration in the trend” rather than “no trend” prior to 60 years ago. There is clearly a linear downward trend prior to that. I don’t think anybody disputes that the rate of increase of atmospheric CO2 has been positive starting about 60 years ago.
justthefactswuwt says:
April 1, 2014 at 8:24 pm
Yes, highly suspect. Roy Spencer assessed C13/C12 Isotope ratios back in 2008;
http://wattsupwiththat.com/2008/01/28/spencer-pt2-more-co2-peculiarities-the-c13c12-isotope-ratio/
Looking further at Spencer’s analysis and wondering that he got exactly the same slope to 5 significant digits (figures 3 and 6), I think he’s screwed up his analysis. He doesn’t show the computations behind those figures, but it’s not apparent how detrending combined C12+C13 concentration in time would affect the C13/C12 ratio at any particular point in time. It appears figures 3 and 6 are precisely identical except for a constant offset, though the difference in axis size obscures this a bit. Perhaps I’m not understanding what he’s done but I think he’s looking for a temporal effect and the analysis discards time. Regardless, I think the premise is flawed as per the previous post.
MarkB says: April 2, 2014 at 6:48 am
I’m not clear why you think Wei etal supports Spencer’s hypothesis.
Because Spencer’s hypothesis, as he laid out here;
http://wattsupwiththat.com/2008/01/25/double-whammy-friday-roy-spencer-on-how-oceans-are-driving-co2/
is that:
“1. The interannual relationship between SST and dCO2/dt is more than enough to explain the long term increase in CO2 since 1958. I’m not claiming that ALL of the Mauna Loa increase is all natural…some of it HAS to be anthropogenic…. but this evidence suggests that SST-related effects could be a big part of the CO2 increase.
2. NEW RESULTS: I’ve been analyzing the C13/C12 ratio data from Mauna Loa. Just as others have found, the decrease in that ratio with time (over the 1990-2005 period anyway) is almost exactly what is expected from the depleted C13 source of fossil fuels. But guess what? If you detrend the data, then the annual cycle and interannual variability shows the EXACT SAME SIGNATURE. So, how can decreasing C13/C12 ratio be the signal of HUMAN emissions, when the NATURAL emissions have the same signal???”
Wei et al.;
http://www.webpages.uidaho.edu/envs501/downloads/Wei%20et%20al.%202009.pdf
found that:
“The long-term variation of seawater pH derived from coral d 11 B record shows robust decadal–interdecadal cycles with periods of 22-year and 10-year over the past 200 years in this region. This suggests that the long-term seawater pH variation in this region is closely related to the decadal–interdecadal variability of atmospheric and oceanic anomalies in Pacific, which agrees with findings by Pelejero et al. (2005) .”
“Such interdecadal fluctuations have also been observed in another coral d 11 B record in Flinders Reef in the adjacent region ( Pelejero et al., 2005 ), which is the only other published long-term coral d 11 B record and also shows a relationship to the Interdecadal Pacific Oscillation (IPO) of ocean-atmosphere anomalies ( Pelejero et al., 2005 ).”
.
“Even though not exactly in phase, the interdecadal fluctuations in the two coral d 11 B records appear to be partially related to the variation of the IPO index, in particular the rapid variations of coral d 11 B correspond to rapid IPO changes. For example, the rapid increase of d 11 B values around 1940 in the Arlington Reef record, approximately corresponds to the rapid shifting of the IPO index from its maximum positive value ( 1.7) in 1940 to its maximum neg- ative value ( 1.7) in 1951 ( Fig. 5 ). It is noted, however, that there are also some inconsistencies with the IPO, in par- ticular the high d 11 B values from 1993 to 1995 followed by the rapid fall in values centered at 1998, suggesting that other factors are also at play.”
As such, Wei et al. found that “long-term seawater pH variation in this region is closely related to the decadal–interdecadal variability of atmospheric and oceanic anomalies in Pacific”, which supports Spencer’s hypothesis that “The interannual relationship between SST and dCO2/dt is more than enough to explain the long term increase in CO2”
As for “Wei et al. only found increasing trends ‘over the past 60 years’”, I read that as an “acceleration in the trend” rather than “no trend” prior to 60 years ago. There is clearly a linear downward trend prior to that. I don’t think anybody disputes that the rate of increase of atmospheric CO2 has been positive starting about 60 years ago.
You can read it as you’d like, but Wei et al. found that:
“The temporal variation of the d11B of the coral from Arlington Reef exhibits an overall decreasing trend since 1940 and obvious interdecadal fluctuations since 1800 as shown in Fig. 4.”
“The positive correlation between coral d 11 B and d 13 C shown in Fig. 7 indicates a correlation between seawater acidification and decreasing DIC d 13 C in this region since 1940.”
“The negative correlation between the SST and the coral d 11 B as shown in Fig. 7 shows a correlation between secular seawater acidification and warming since 1940. Increasing SST decreases the solubility of CO 2 in seawater and may therefore partially mitigate the trend of decreasing pH.”
MarkB says: April 2, 2014 at 10:56 am
Looking further at Spencer’s analysis and wondering that he got exactly the same slope to 5 significant digits (figures 3 and 6), I think he’s screwed up his analysis. He doesn’t show the computations behind those figures, but it’s not apparent how detrending combined C12+C13 concentration in time would affect the C13/C12 ratio at any particular point in time. It appears figures 3 and 6 are precisely identical except for a constant offset, though the difference in axis size obscures this a bit. Perhaps I’m not understanding what he’s done but I think he’s looking for a temporal effect and the analysis discards time.
I do not have any further insight into his computations, but I do note that the thread was live for almost year and had 158 comments, many quite challenging, and no one raised the concern that you have. If you think “he’s screwed up his analysis”, I recommend posting a comment on his blog;
http://www.drroyspencer.com/
stating as such and requesting his computations for validation.
Regardless, I think the premise is flawed as per the previous post.
Roy framed his hypothesis out further here:
http://www.drroyspencer.com/2009/01/increasing-atmospheric-co2-manmade%E2%80%A6or-natural/
I am not going down a rabbit hole with you on the relationship between anthropogenic CO2 emmisions and increased atmospheric CO2 post 1950. The point of this article was to demonstrate that;
“claims that “Global warming is the unusually rapid increase in Earth’s average surface temperature over the past century” are erroneous and indicative of either ignorance or duplicity on the part of NASA’s Earth Observatory, NASA’s Climate Consensus page, The Daily Mail, the EPA and many others.”
and given that no one has been able to demonstrate a potentially consequential anthropogenic contribution to CO2 prior to 1950, or a relationship between potentially consequential anthropogenic CO2 and Global Warming prior to ~1975, I believe I’ve done that.
Thanks for the additional link to Spencer’s blog. I was disappointed at first to see that comments on that thread appear not to be visible, but I see that he’s posted a thoughtful response by Engelbeen in the following article. When I find time, I’ll try to better digest both.
My particular issue with your article is that an indictment of “either ignorance or duplicity” is a strong statement that calls for a stronger case than you’ve made in my view. The combination of warming over that period, the increase in CO2, and a probable anthropogenic isotope signature to that increase make a century long significant causal contribution plausible. While that may ultimately prove to be an erroneous interpretation, being wrong is a far different thing from being duplicitous.
In any case, thank you for the time you’ve taken to respond to my concerns.
In the late Ordovician, the planet plunged into the Andean Saharan ice age and later emerged from it while the CO2 level was about 10 times the present.
During the last glacial period, warming trends changed to cooling trends while the CO2 level was higher than it had been during the warming trend.
During the 20th century, average global temperature trends went down, up, down, up while the CO2 level went steadily, progressively up. Lack of correlation demonstrates lack of causation.
To see further discussion of these three issues, search keywords Pangburn Middlebury.
These things corroborate that CO2 change, by any rational amount, whether anthropogenic or not, has no significant effect on climate.
Natural climate change has been hiding in plain sight. Simple equation calculates temperatures since before 1900 with 90% accuracy (95% correlation) and reasonable estimates since the depths of the LIA. CO2 change had no significant effect. Search using keywords ‘AGW unveiled’.
MarkB says: April 3, 2014 at 7:10 am
Thanks for the additional link to Spencer’s blog. I was disappointed at first to see that comments on that thread appear not to be visible, but I see that he’s posted a thoughtful response by Engelbeen in the following article. When I find time, I’ll try to better digest both.
Also for reference E.M.Smith researched C13/C12 ratio in this article;
http://chiefio.wordpress.com/2009/02/25/the-trouble-with-c12-c13-ratios/
and “In wandering off to learn more about C12 / C13 origins and ratios I ran into this gem. It does raise the interesting question: If human CO2 dropped dramatically during the great depression, where is the signature in the record?”
From: http://www.thenation.com/doc/20070611/cockburn
“I should acknowledge one imprecision in my description of Dr. Martin Hertzberg’s graph in my first column–”the smoothly rising curve of CO2″–which prompted several intemperate responses, charging that I couldn’t possibly expect CO2 or carbon levels to drop just because of a one-third cut in manmade CO2. Indeed, I should have written, “One could not even see a 1 part per million bump in the smoothly rising curve.” Even though such transitory influences as day and night or seasonal variations in photosynthesis cause clearly visible swings in the curve, the 30 percent drop between 1929 and 1932 caused not a ripple: empirical scientific evidence that the human contribution is in fact less than a fart in a hurricane, as Dr. Hertzberg says.”
Willis Eschenbach wrote about 13C/12C ratio in this article;
http://wattsupwiththat.com/2010/06/07/some-people-claim-that-theres-a-human-to-blame/
and thought that “This isotopic line of argument seems like the weakest one to me.” “fossil fuels in the current mix have a 13C/12C ration of ~ -28 per mil, only about half of that requried to make such a change. So it is clear that the fossil fuel burning is not the sole cause of the change in the atmospheric 13C/12C ratio. Note that this is the same finding as in the Nature article.”
http://www.nature.com/nature/journal/v279/n5710/abs/279229a0.html
“THE stable carbon isotopic (13C/12C) record of twentieth-century tree rings has been examined1-3 for evidence of the effects of the input of isotopically lighter fossil fuel CO2 (δ 13C~-25‰ relative to the primary PDB standard4), since the onset of major fossil fuel combustion during the mid-nineteenth century, on the 13C/12C ratio of atmospheric CO2(δ 13C~-7‰), which is assimilated by trees by photosynthesis. The decline in δ13C up to 1930 observed in several series of tree-ring measurements has exceeded that anticipated from the input of fossil fuel CO2 to the atmosphere, leading to suggestions of an additional input ‰) during the late nineteenth/early twentieth century. Stuiver has suggested that a lowering of atmospheric δ 13C of 0.7‰, from 1860 to 1930 over and above that due to fossil fuel CO2 can be attributed to a net biospheric CO2 (δ 13C~-25‰) release comparable, in fact, to the total fossil fuel CO2 flux from 1850 to 1970. If information about the role of the biosphere as a source of or a sink for CO2 in the recent past can be derived from tree-ring 13C/12C data it could prove useful in evaluating the response of the whole dynamic carbon cycle to increasing input of fossil fuel CO2 and thus in predicting potential climatic change through the greenhouse effect of resultant atmospheric CO2 concentrations. I report here the trend (Fig. 1a) in whole wood δ 13C from 1883 to 1968 for tree rings of an American elm, grown in a non-forest environment at sea level in Falmouth, Cape Cod, Massachusetts (41°34′N, 70°38′W) on the northeastern coast of the US. Examination of the δ 13C trends in the light of various potential influences demonstrates the difficulty of attributing fluctuations in 13C/12C ratios to a unique cause and suggests that comparison of pre-1850 ratios with temperature records could aid resolution of perturbatory parameters in the twentieth century.”
My particular issue with your article is that an indictment of “either ignorance or duplicity” is a strong statement that calls for a stronger case than you’ve made in my view. The combination of warming over that period, the increase in CO2, and a probable anthropogenic isotope signature to that increase make a century long significant causal contribution plausible. While that may ultimately prove to be an erroneous interpretation, being wrong is a far different thing from being duplicitous.
I disagree, duplicity is defined as “contradictory doubleness of thought, speech, or action; especially : the belying of one’s true intentions by deceptive words or action”:
http://www.merriam-webster.com/dictionary/duplicity
On page 2 of the NASA Earth Observatory site it says that;
http://earthobservatory.nasa.gov/Features/GlobalWarming/page2.php
“Global warming is the unusually rapid increase in Earth’s average surface temperature over the past century primarily due to the greenhouse gases released as people burn fossil fuels.”
On page 4 of the NASA Earth Observatory site it says that;
http://earthobservatory.nasa.gov/Features/GlobalWarming/page4.php
““Climate model simulations that consider only natural solar variability and volcanic aerosols since 1750—omitting observed increases in greenhouse gases—are able to fit the observations of global temperatures only up until about 1950.”
That is essentially the exact definition of being duplicitous.
In any case, thank you for the time you’ve taken to respond to my concerns.
No problem, I am happy to respond to criticism and welcome more of it in the future.
Well carbon dating organic materials, like tree rings, only started in 1949. Cl4 has a half life and decays in dead organic material. Measuring the amount of C14 remaining gives an approximate age of the artifact, but only organic material. But – C14 has increased in the lower atmosphere at various times, due to the earths changing magnetic field, bombardment from outer space, and atom bomb explosions at various times over the millennium. Ain’t science wonderful, eh?
As a post script to the above, when I went on digs, one of my cranky tutors, told me I could not handle or come near artifacts if I smoked. He told me one scientific Carbon 14 dating was thrown out because the archaeologist dropped cigarette ash and contaminated the artifact. I never liked him either, but that is irrespective. Nothing is perfect or absolute.