For the period of interest, where the
ppmv peak value of CO2 is situated (1943) that gives this graph:
Minima and averages of historical CO2 data 1927-1953 as collected from
the literature by Ernst Beck, from [6
Except for fall data measured in Vienna (average minima above the 500
ppmv graph maximum!), all minima are below the ice
core data. As the ice core contains smoothed values (average 8 years
smoothing), this levels out fast CO2 variations in the atmosphere. But
the averages measured over land in the period 1935-1950 (15 years) is
about 100 ppmv higher than in the ice core. That proves that the land
based measurements show positive biased values, which have no
resemblance to the real historical background (which was already
obvious in the previous chapter). Current background values over the NH
(including selected values at Schauinsland, Germany, at 1,000 m
altitude) show only a difference of less than 5 ppmv with the South
Pole measurements. And South Pole atmospheric measurements overlap with
ice core measurements for a period of about 20 years within the error
margins (+/- 1.3 ppmv).
Further, there is a discrepancy between the averages Beck calculated
and reality: Beck averaged as a matter of speaking 1,000 datapoints
from Giessen with 10 from Philadelphia and 10 from over the oceans,
thus giving 100 time more weight to Giessen than to the other two. For
a "global" average, this is quite remarkable. The take on this by peterd
Table 3 is a summary of data measured between 1868 and 1956 (ie.., just
at the point where Keeling Sr comes on the scene). The MAJORITY of
these values indicate CO2 around 310 ppm. The high (>400 ppm) values
emphasized by Beck belong to a rather small minority of workers. It is
as if, out of 100 people doing the same measurement (though maybe by
different methods), 99 of them agreed quite well, but the 100th, who
nevertheless produced a data set vastly greater than the other 99, was
given preferred status, simply because he produced more numbers. Does
this sound reasonable? Does this sound scientific? Yet this is
precisely what Beck has done, in according preferred status to the high
values. Nowhere does he offer any explanation as to why these high
values should be believed.
I only can agree with his words...
probability of a huge peak around 1943.
you look at the previous graph to the averages, there is a huge peak in
CO2 around 1943. That is a very fast one: from the base line in 1936 at
around 330 ppmv (historical) to 430 ppmv in 1943. That is 100 ppmv in
only 7 years time. The same the other way out: back down to the
baseline of 330 ppmv in 1953, again 100 ppmv in only 10 years time.
That is a huge amount of CO2 which must come and go from/to another
reservoir. Such huge movements aren't seen in any year of
accurate measurements since 1959. The maximum variability in recent
times is +/- 1 ppmv/yr.
But let us assume that the figures are right. Well, the release of 210
GtC (= 100 ppmv) in 7 years time is theoretically possible as result of
a huge release from volcanoes, (undersea) vents, meteorite impacts,
etc... Or burning 1/3th of all vegetation on earth... There is no sign
that something like that happened, but it is possible. But the opposite
way: that 210 GtC were absorbed in ten years time, either by vegetation
(that is one third of all vegetation as extra growth) or oceans, is physically impossible
. There simply
is no process in the natural world which can absorb such a quantity of
CO2 in such a short time. This in fact refutes the probability of such
a peak value around 1943.
We have other sources of CO2 measurements or proxies which may give a
hint of CO2 variability around 1943. None of these show a specific
variability around 1943, which should be present if the atmospheric CO2
content increased and decreased with 30% in such a short period. Have a
1. ice cores.
Here an overview of ice core measurements, including the period around
1943. Two of the Law Dome ice cores have a resolution of less than a
decade. A peak of 100 ppmv thus should show at least 10 ppmv peak in
the ice core, even more in this case, as the peak value was high during
9 years. But it isn't visible, except for a small irregularity of about
1 ppmv, but too early, in 1938. In fact there is a dip around 1943, but
that has little relevancy, as the datapoints are within the accuracy of
the measurements of 1.2 ppmv (1 sigma) for the same core (5 ppmv
between ice cores for the same gas age).
CO2 levels in ice cores around the 1943 "peak" of historical data [8
2. Stomata data.
Although stomata data have their own problems (positive bias due to
local/regional CO2 sources) quite similar to the historical data, they
don't show a peak value around 1943:
CO2 levels vs. stomata data calibration in the period 1900-1990 [9
This is the calibration curve of stomata data vs. CO2 in the
atmosphere, firn and ice cores, done for the period 1900-1990. If there
had been a peak of 80 ppmv around 1943 (that is at 310 ppmv in the ice
cores), the stomata index (SI) should have reacted with an extreme low
value at the 310 ppmv point. But nothing special can be observed.
3. Coralline sponges.
Coralline sponges grow in shallow waters in the tropics. The carbonates
built into the sponges follows the isotopic composition (d13C or
13C/12C ratio) of CO2 in the surrounding water, without modification.
But as shallow waters track the CO2 in the atmosphere, the composition
changed over the years since the start of the industrial revolution. If
there was a huge release of CO2 in the atmosphere around 1943, this
must be seen in the d13C ratio, as such a release from vegetation
should give an enormous drop in d13C (about 4 per mil decrease, but
flattened by the seasonal exchanges), while such a release from the
(deep) oceans should give an important increase in d13C (about 1.6 per
mil increase, but flattened by the seasonal exchanges). But there is
no visible change in trend around that period:
d13C evolution in coralline sponges [10
Again, there is no sign of anything happening around 1943, even if the
d13C records have a high resolution of 2-4 years around that period and
the accuracy is fine enough to detect an extra addition/uptake of 1 GtC
(0.5 ppmv) from/by vegetation or 4 GtC (2 ppmv) from the (deep) oceans.
Thus all we can say is that other
(proxy) methods, even with high resolution, don't show any abnormal
variation around 1943.
I respect the amount of work done by Beck to look at the historical
data, I only can disagree to a large extent with his conclusions.
Besides the quality of the measurements themselves, the biggest problem
is that most of the data which show a peak around 1943 are taken at
places which were completely unsuitable for background measurements. In
that way these data are worthless for historical (and current) global
background estimates. This
is confirmed by other methods which indicate no peak values around
the minima may approach the real background CO2 level of that time, the
fact that the ice core CO2 levels are above the minima is an indication
that the ice core data are not far off reality.