Few, if any, dispute that atmospheric CO2 levels have been increasing since the industrial revolution. What is in dispute is the effects of this. The prevailing media narrative is that “OMG we’re all gonna die!” but this is an interesting post.
7 thoughts on “The Greening Of The Earth”
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I have come to regard as a possibility that the increase in atmospheric CO2 is only partially the result of human activity, perhaps only half of this increase, with the remaining portion the result of thermally stimulated CO2 emission from soils and other natural sources on account of warming.
That the thermally stimulated emission, a strong positive feedback, doesn’t result in a runaway increase in CO2 is that the “greening” of plants supplies a countervailing negative feedback. In the absence of a thermally stimulated component of emissions along with a strong response of plants to absorb CO2 in response to atmospheric conditions, my carbon model has nearly all of the CO2 increase in the atmosphere the result of human-caused emissions.
One can get a good estimate of the CO2 being emitted from fossil fuel consumption, because one can get a good estimate of fossil fuel consumption. It’s not like there’s huge uncertainty in how much carbon is in that fossil fuel.
When you do that, you find the current annual CO2 increase is less than the CO2 released in burning the fossil fuels. There are natural processes, but they are net removing CO2 from the atmosphere, not adding it.
It is well known, quantitative observation that of the CO2 emitted by humans, the increase in atmospheric CO2 is half that amount. The Standard Carbon Model has all of the atmospheric increase attributable to that half of the human-caused emissions, with the remaining human-caused emissions about equally split between ocean and a land sinks.
That ocean sink is regarded as being an inorganic process — CO2 “dissolved” (actually chemically reacted) into ocean water. The land sink is regarded as being the action of plants, an organic process. Highly precise measurements of minute changes in atmospheric oxygen support this split, where organic CO2 sinks give back the oxygen taken up when fuel is combusted whereas the inorganic CO2 sinks do not give back that oxygen.
The “half-of-the-half” of human-caused CO2 going into ocean water is consistent with what is known about the uptake of atmospheric CO2 into ocean water. This ocean sink is not going to saturate any time soon as the capacity of the ocean to hold CO2 is vast — some 50 times greater than the atmosphere. The rate at which the ocean sinks CO2, however, is “throttled” by equilibrium chemistry along the chemical pathway by which CO2 is bound to ions and other chemical species in ocean water. Owing to the non-linearity of that chemical reaction, a 10-fold increase in bulk atmospheric CO2 concentration results in only a 1-fold increase in CO2 in the surface ocean layer, and it takes time for the surface ocean water to mix with that in the deeper ocean. The chemical pathway is well known by the mixing rate is speculative, but the mixing rate parameter can be “tuned” to account for the observed ocean/land CO2 sink split established by measurement of atmospheric O2.
The precise numbers on the land CO2 sink are less well measured, the processes quantified and hence known apart from the land must make up the other half of the CO2 sink. There can be and in indeed there must be significant flows of CO2 back and forth with the atmosphere — these are large compared to the human-caused emission regarded as making up most of the 20th century increase in CO2 — the Keeling Curve named after Keeling who set up an observatory on the big island Hawaii to measure atmospheric CO2.
What I am arguing is that if there is any uncertainty in the Carbon Cycle and Carbon Balance it is on the land side as the ocean processes are much better described, measured and quantified, although Bart who comments here disputes me on this. His argument is that ocean mixing is not uniform — think El Nino and other changes in ocean upwelling — and this nonuniformity makes the ocean CO2 exchange less certain than I make it.
Considering the land side of things, I consider a model where increase in atmospheric temperature stimulates CO2 emission from organic matter in soils that got there from dead plants whereas increase in atmospheric CO2 concentration stimulates the uptake of CO2 by plants — I got this idea from Murry Salby, a published atmospheric scientist who is currently regarded as a crank for disputing Carbon Cycle orthodoxy. I regard Murry Salby’s claim that very little of the increase in atmospheric CO2 is from humans and most from natural CO2 emission stimulated by warming to be wrong, and his understanding of ocean water treats it like a linear system — like an electrical RC circuit — which is known to be wrong in light of understanding of the highly non-linear nature of the inorganic/chemical ocean sink.
The elephant-in-the-room pointed out by Salby, however, is that the rate-of-increase in atmospheric CO2, what he calls “net emission”, fluctuates by large amounts compared to the human-caused emissions and this fluctuation correlates with atmospheric temperature, and according to Salby (I need to study his arguments better), this correlation is uniform “at all time scales.”
Assuming this uniformity, I “tune” parameters for plant sensitivity to increase CO2 in the atmosphere — the “greening” Rand linked to — and for the temperature-stimulated emission of CO2 from soils — increased temperature speeds bacterial decomposition of organic carbon back into CO2. As far as the land/ocean CO2 split, I “tune” for that known value too, but allow for greater flux out of the land from the thermally stimulated emission and greater flux back into plants by “greening.”
Tuning these parameters to match both the Keeling curve bringing us recently past 400 ppm atmospheric concentration along with the fluctuation in “net emission” with global temperature records, my carbon model shows that only about half of the 20th century increase in atmospheric CO2 can be blamed on humans. The model also shows that on account of the “greening” effect, the time for CO2 to revert to “normal” is much shorter than the hundreds of years claimed by the IPCC.
Whereas Salby promotes heretical thinking on CO2, the keeper of Carbon Cycle orthodoxy is Pieter Tams at NOAA, who claims that the CO2 reservoir from which the thermally stimulated emission occurs is shallow — mainly tropical forest leaf litter — the correlation between temperature and net emission is short term — only over 1-3 years, and most of the increase in atmospheric CO2 stays blamed on humans.
On the other hand, there is a recently published paper in Nature Letters quantifying CO2 emissions from temperate-zone soils that supports the thermally stimulated emissions happening over decadal time horizons, giving a number supporting my model.
Why do the AGW cultists hate plants?
Global Warming Catastrophism is a political movement not a scientific theory. Catastrophism is about as “scientific” as Scientific Socialism!
The leaps of logic they make to get from measurement of increased CO2 to actions like deindustrialization/carbon-taxes/Paris-Accord are jaw dropping and never properly addressed. Truly an underpants-gnome train of logic!
And the weakest link of all has been the presumption that increased global temperatures and increased atmospheric CO2 was bad for humanity. When you probe the catastrophists they have no good answer why they make such a presumption. They automatically assume the temperature of 1970 is the ideal temperature, with no good reasons to back any of that up.
I remember back in 1996, after I attended a presentation on global warming catastrophism how annoyed I was at all the unspoken assumptions of the panelists as they glibly presented their ideas to the audience. So I pigeonholed one of the panelists afterwards and confronted him with the key question of ‘how do they know what is the ideal climate for humanity considering the enormous shifting of global climate we know happens naturally over hundreds of thousands of years?’, and he admitted they just assume 1970 global climate is the ideal. I was shocked.
The temperature of 1970 is ideal because January 1, 1970 is the UNIX Epoch. I thought that was self-evident. 😉
What year, again, was the first Earth Day? ?