Guest essay by Ronald D Voisin
(For the Ice-Core “Near-Perfect-Recordation” Enthusiasts)
Ice-cores analysis has provided many valuable insights into past climate. We can be more confident for some of these insights than others. One troubling insight surrounds the peaks of historic CO2 atmospheric concentration. In this essay, I would like to describe what I believe would be an “ideal” description of the recordation process regarding the amplitude of the peaks of historic CO2 atmospheric concentration.
Let’s assume that the following atmospheric perturbation is to be recorded in the ice (see Figure 1). At some point in time t0, atmospheric CO2 rises from a background concentration of 300ppm, at 3ppm/year, for 100 years. It peaks at 600ppm representing a 100% spike from the original background concentration and then falls in a similar fashion during the ensuing 100 years. The amplitude and duration of the perturbation are arbitrary but, I think, potentially representative of prior real-world events (and possibly we are just now 60 years into recording the beginning of a somewhat similar event at Mauna Loa currently). So how might this atmospheric perturbation be captured (recorded) accurately in Antarctica ice?
First let’s describe the initial conditions for the recording media, at t0 and prior, which might be typically found at a drill site in Antarctica (see Figure 2). On the surface there are a couple meters of loose snow blowing around. Under that there is ~100 meters of firn – partially compacted snow that has been left over nominally in layers from previous seasons of snow. The seasonal age of the bottom of the firn is typically 40 years. Under that there is glacial ice going down to great distance formed from the weight pressure of the firn. This glacial ice represents past seasons, nominally in layers, from 40 years to as many as 800,000 years. Atmospheric CO2 is initially at 300ppm.
In Figure 3 we have a snapshot of the atmospheric CO2 recordation at t0 plus 50 years. During these 50 years the atmospheric CO2 concentration has grown from 300ppm to 450ppm at 3ppm/year. The latter 40 years of the 50 are recorded in the firn while the first 10 years have now progressed into the glacial ice. In Figure 4 another 50 years of recordation have occurred. At t0 plus 100 years, atmospheric CO2 is now peaked at 600ppm. Again the latter 40 years are recorded in the firn while the initial 60 years have now progressed into the glacial ice.
In Figure 5 below we are now on the downside of the atmospheric perturbation to be recorded. Atmospheric CO2 has now fallen from a 600ppm peak back down to 450ppm. As before the most recent 40 years are in the firn; and 110 years of recordation have progressed into the glacial ice; including the atmospheric peak at 600ppm.
Atmospheric concentration perturbations of differing amplitude and duration would, I think, produce similar “ideal” results.
And this is what many alarmists believe and represent (actually skeptics and alarmists alike). i.e. The ice cores are often represented (by ice-core near-perfect-recordation enthusiasts) in such a way that we are told that the atmospheric CO2 of today, at 400ppm, is at the highest level ever for 800,000 years; that the ice-core data show this is so; that the ice-cores faithfully record the peak CO2 concentration which has never been so high as 400ppm.
However, do WUWT readers see any problems with this “ideal” characterization of the ice-core recordation process? I do…and bigtime. In a future post I’ll detail my issues with this ideal portrayal but for now, can WUWT readers help me by sharing their concerns and recommendations? (Let’s not quibble too much about the “Depth Below Surface” numbers. I realize that in reality the glacial ice would likely be more compact, the spikes and gradients yet more abrupt, but have chosen my numbers for graphic convenience.)
Hints (as to exactly where the future essay is heading):
There are very substantial concentration gradients to drive diffusion processes. There are alternating seasonal temperature gradients pumping away to create activity in the system. There is an, ever present, enormous pressure gradient; giving rise to a density gradient; in turn giving rise to a diffusion mobility gradient.
The high quality recordation in Figures 3 and 4, where atmospheric CO2 is higher than what has been previously recorded, is likely quite different from the subsequent low quality recordation where atmospheric CO2 is falling*. After a hundred thermal cycles, while atmospheric CO2 is falling, just where might a thinking and reflectful engineer imagine that a great deal of that CO2 would return to?
And this is all occurring at the initial outset of ice-core recordation process (first few hundred years) notwithstanding an array of big-deal in situ and subsequent recordation distortions – each and every one of which specifically and selectively diminishes “peak CO2” recordation…selectively.
*The ice-core “Near-Perfect-Recordation” Enthusiasts are quick to point out that the firn today captures accurately the ever increasing trend observed at Mauna Loa. This is a false positive confirmation. A time will come when atmospheric CO2 is falling and that is when we will readily observe the diffusion attenuating distortion subject of this essay.
Let me say that again with different words.
A great many anomalies surround ice-core CO2 recordation of peak perturbation. Some are big (several), many are medium to small. One big anomaly (signal attenuation) comes at the outset of the recordation process (the subject of this essay). And individually each one, and more consequentially when summed collectively, all anomalies seriously diminish the CO2 peaks. And there is no known anomalous process that could have ever acted otherwise. i.e. No known process can act in such a way as to not diminish the CO2 peaks; no known anomaly can possibly make the peaks more peaked than reality. All metrological imperfections act in such a way as to diminish the recorded peaks of CO2 – and quite significantly and selectively at the peaks.
In this 200 yearlong 100% perturbation example I estimate that no more that 10% of the original signal can survive the initial attenuation of the recordation process, let alone the subsequent and substantial further attenuating distortions.
CAGW isn’t just wrong…it’s entirely and antithetically wrong. Rather than climatic poison, elevated atmospheric CO2 is the elixir of all life on Earth. And misinterpretation/misunderstanding of the ice-cores has contributed greatly to our ongoing confusion. For more info see here.
Ronald D Voisin is a retired engineer. He spent 27 years in the Semiconductor Lithography Equipment industry mostly in California’s Silicon Valley. Since retiring in 2007, he has made a hobby of studying climate change. Ron received a BSEE degree from the Univ. of Michigan – Ann Arbor in 1978 and has held various management positions at both established semiconductor equipment companies and start-ups he helped initiate. Ron has authored/co-authored 31 patent applications, 27 of which have issued.