ClimateSIM Junior, Simplified Prognostication from Unrealistic Hypothesis
Let me call the complicated work of supercomputer climatologists “ClimateSIM Senior.” Their efforts result in very complex “computer games” that simulate, up to a point, the Earth’s climate history, past and future.
What follows is a description of “ClimateSIM Junior,” my “speculative science” effort to model Earth’s climate, using formulas devised on pads of paper and numbers arrived at with a hand-held calculator (HP45). My purpose here is to present a simplified and only mildly inaccurate picture of “what is,” and to project from that with complete positive thinking, to ‘guesstimate’ “what could be.”
For data, I used the summary of the Carbon Cycle as published by the IPCC in 2007 (reporting on 2004 data), and a variety of estimates I have made and reported on over the course of the last year. The numbers to be presented are all internally consistent for the ease of storytelling, but the realities they represent are not actually known to the exactitude implied by the numbers shown.
Finally, I am not competing with nor contradicting ClimateSIM Senior, just trying to understand it better.
In 2020, the anthropogenic emissions of carbon dioxide gas (CO2) from Earth’s land surfaces is 36.3Gt/y (Gt/y = giga metric tons per year, or units of 10^12kg/year). This composite plume is split between industrial CO2 pollution, at 29.3Gt/y, and land use (or misuse) CO2 pollution at 7Gt/y.
Natural emissions of CO2 from land surfaces are: 0.3Gt/y from volcanoes, and 440Gt/y from respiration. The total of CO2 emissions from land surfaces is 476.6Gt/y.
The yearly absorption (or fixing) of CO2 from the atmosphere by land surfaces has three components: 0.7Gt/y by weathering reactions on soils and rocks; 440Gt/y by photosynthesis as in the pre-industrial past; and an additional 0.4Gt/y by photosynthesis in recent years. The total absorption of CO2 by land surfaces is 441.1Gt/y.
At present, land is a net emitter of CO2, at the rate of 35.5Gt/y, all anthropogenic.
The natural emissions of CO2 by the oceans, at present, are: 260Gt/y of CO2 released as in the pre-industrial past; and an additional 70Gt/y released in recent decades. The net emission from the oceans is 330Gt/y.
The uptake or absorption of CO2 by the oceans is: 260Gt/y as in the pre-industrial past; with an additional absorption of 80.4Gt/y in recent decades. The net absorption by the oceans is 340.4Gt/y.
At present, the oceans are net absorbers of CO2, at the rate of 10.4Gt/y, all anthropogenic.
With lands emitting 35.5Gt/y, and oceans absorbing 10.4Gt/y of it, CO2 is accumulating in the atmosphere at the rate of 25.1Gt/y, which is equivalent to a rise in the partial pressure of atmospheric CO2 of +3.2ppm/y (ppm = parts per million). We are at 417ppm now; if nothing changes then in one year atmospheric CO2 should be at 420.2ppm.
The anthropogenic accumulation of CO2 in the oceans is 481.2Gt (my estimate; “500Gt” or “about 500Gt” are casually stated elsewhere), and the average acidity level of the oceans is at a pH of 8.1. Today’s oceans are 26% more acidic than they were in pre-industrial times, when their pH was 8.2.
Now let’s dream. Imagine that all anthropogenic CO2 emissions cease immediately and permanently. The lands would become net absorbers of CO2, at the rate of 0.8Gt/y (by weathering reactions despite volcanic outbursts, plus lingering added photosynthesis). This clearing rate is equivalent to -0.10ppm/y. The 137ppm of excess CO2 above the pre-industrial level of 280ppm would be cleared away in 1,359 years. Further accumulation of CO2 in the oceans will have ended with the cessation of anthropogenic emissions.
The global temperature would continue to rise (because of atmospheric and oceanic heat-retention effects at a higher temperature than in pre-industrial times), but at a slower and slower rate, peaking at +3.8°C of average global warming above the temperature of 1910 (and +2.8°C above today’s global average temperature), for the century 300 to 400 years from now. Cooling would ensue thereafter, with a return to pre-industrial (1910) conditions in about 1,350 years from today.
By that time the terrestrial part of the Carbon Cycle would have returned to its pre-industrial level of performance, with the land surfaces acting as net absorbers of atmospheric CO2 at the rate of 0.4Gt/y, equivalently -0.0504ppm/y of atmospheric CO2 reduction.
With the atmosphere cleared of anthropogenic CO2, and its partial pressure reduced to its pre-industrial level, the oceans could begin an extra release plume of CO2 gas at a rate of 0.4Gt/y, to be fixed by weathering reactions on land. The atmospheric concentration of CO2 would remain stable at 280ppm (with minor natural fluctuations). The anthropogenic load of CO2 in the oceans would be cleared in 1,203 years, and their acidity would return to their pre-industrial level of 8.2pH.
Nearly all of the anthropogenic caloric load accumulated by the biosphere is stored in the upper 500 to 1,000 meters of the oceans, and is concentrated at the top. With the onset of atmospheric CO2 reduction and overall biosphere cooling (more heat, as infrared radiation, being radiated into space without being blocked by an excessive CO2 “thermal blanket”), oceanic anthropogenic heat would be able to diffuse out of the waters and radiate away. Over the 1,203 year time span of oceanic de-acidification, the excess heat stored in the upper 73 meters of the oceans would be radiated away (and excess heat from the cooler depths will have diffused closer to the surface).
Logically, there would be an overlap in the time spans over which the air and oceans, respectively, are cleared of their anthropogenic loads of CO2 and excess heat, but to calculate that with any degree of believability is a job for ClimateSIM Senior.
Today, this is the best unified story I can tell about the most optimistic hypothetical case for Earth’s recovery from global warming. It lies somewhere between a quantitative engineering estimate, and a dream.
Now for some policy recommendations. My suggestions to the Economic Mandarins of the United States are as follows:
If those Mandarins are Neoliberals:
1. Use that bloated, over-equipped U.S. military colossus to invade Brazil and gain control of the Amazon Basin. Then, stop the fires, kick out the ranchers and miners, and rehabilitate the rainforest “lungs of the Earth” to tamp down the onslaught of global warming. Also, help out the Brazilian people while you are at it.
2. A second target for the same type of action as in the above, is Siberia. But be sure not to spark a nuclear war in trying to gain control of it (so, don’t be too hasty, and also use diplomacy). Remember, stabilizing the geophysical climate aids in stabilizing a reliable business climate.
If those Mandarins happen to become Socialists:
1. Use that bloated, over-equipped U.S. military colossus — if you are unwilling to dismantle it because it is a “public works” program — to implement the 2 recommendations given to the Neoliberal Mandarins.
2. Also, immediately invade all offshore tax havens (many concentrated in the Caribbean) to repatriate tax-avoiding hoards hidden there. Use those stolen-from-the-public funds to underwrite the costs of maintaining the lives, for life, of all the nation’s people.
3. A good portion of the funds liberated from militarized and pirated-private sequestration will necessarily go to mitigating the impacts of global warming, in a variety of ways applied regionally.
4. It will also be necessary to contribute to international efforts at global warming mitigation and standard-of-living equalization, to simultaneously help meet national goals in those regards.
Being realistic, nobody really wants to hear about global warming, whether they are in government, business, or an “ordinary” member of the pubic. Government people don’t want any interruptions to their careers being in positions of power (and making money); business people don’t want any interruptions to their careers making money (and being in positions of power); and most members of the public just want an uninterrupted continuation of their comforts and entertainments — if they are not in absolute terrified panics over threats to their physical and economic survival, and don’t have the luxury of worrying about global warming.
As a result, there is no limit to how bad we can make global warning; which the Trump Administration (in the U.S.) and the Bolsonaro Administration (in Brazil) seem to be taking as a challenge.
In terms of dreams of utopia versus fears of doom and perdition, realize that the best utopia we could achieve would pale in comparison to our dreams about it, but be far superior to the conditions we live under today. If we are doomed by fate regardless of what good efforts we can make at improvement, then we will all drown together in that doom, whether we do so while exploiting each other mercilessly and quarreling bitterly, or whether we do so supporting each other in admirable solidarity. It is our epitaph to choose: nobility or ignominy. And, if we choose the former, an epitaph won’t be necessary.