Interesting Data on the Carbon Cycle.
[I have been rereading a book from the early 1980s. I cam across an article that I found very relevant to our current situation in 2024, not that the other articles are not insightful, too. This article dealt with global warming. Following are two particularly good (for the time) excerpts on carbon flows. Note that the values provided are mostly for carbon, not carbon dioxide. Ed.]
Baes Jr, CF, HE Goeller, JS Olman, and RM Rotty. Carbon Dioxide and Climate: The Uncontrolled Experiment. In Skinner, BJ, ed., 1981. Use and Misuse of Earth’s Surface. A volume in the series Earth and Its Inhabitants. Readings from American Scientist. pp. 87-97.
Excerpt (p. 88).
At the current concentration of 330 ppm of CO2, the atmosphere contains about 700 Gt of carbon. This is substantially less than the carbon stored in living and dead by a mass on land parenthesis (~1800 Gt), somewhat more than that stored mostly as inorganic carbon in the well-mixed surface waters of the ocean, and much smaller than that stored in the deep oceans (~32,000 Gt). The fluxes of carbon between the land and the atmosphere from photosynthesis (gross primary production) in one direction and respiration, decay, and fires in the other are estimated to be ~113 Gt/yr, and between the oceans and the atmosphere [to be] ~90 Gt/yr. Thus, substantial portions of the carbon in the atmosphere in the surface waters of the ocean and on land are circulated each in the carbon cycle. Quite obviously, the relatively small amount in the atmosphere can be appreciatively influenced by any changes in the major fluxes and pools of the cycle.
Most of the land biomass is present as relatively slowly exchanging material: humus and recent peat (~ 1000 Gt) and larger, long-lived stems and roots of vegetation (~600 Gt). Only a relatively small fraction parenthesis (~160 Gt) is present as rapidly exchanging material: small stems and roots, litter, etc.
…[M]an can have a significant influence on the fluxes between the land and the atmosphere. If, for example, he could cause the living biomass (~600 Gt) to increase at a rate of 1% per year, this would more than counterbalance the current annual production of CO2 from fossil fuel (~5 Gt/yr). Since woods have more carbon per hectare, this could be accomplished by conversion of more lands to woods. However, the maximum increase in biomass that could be realized would be small compared to the total mass of fossil carbon(~7300 Gt) that man might ultimately consume.
Actually, it is more likely that the biomass is being reduced by the activities of man…
Excerpt (pp.96-97)
If the present predictions are correct, not long after the year 2000, the warming effect of increased atmospheric CO2 could become conspicuous above the noise level from other causes of climate fluctuation. However, the momentum of societal fuel-use patterns may make it difficult then to adjust from fossil energy to nonfossil energy quickly enough to avoid eventual severe consequences. Hence, the time available for action may be quite limited.
Quite clearly, we must improve our predictions of the consequences of increased atmospheric CO2. The largest uncertainty is this specific effect of any given increase on the regional climate of the world. As a consequence, the first priority should be given to the study of possible climate changes. A better understanding of the carbon cycle is also needed to project better the rate of increase of atmospheric CO2. Finally, we must learn to project the impact of the climatic changes on man, his environment, and his society.
As the potential consequences of various scenarios of energy development become more clearly foreseeable, these must be included in cost-benefit analysis. Depending upon the severity of our energy problems, it may be expected that nonfossil fuel options (such as fusion and breeder reactors for central station generation of electric power, and wind, solar and geothermal energy for dispersed sources) will be increasingly brought into use. One nonfossil fuel option being more actively considered is the use of cultivated waste biomasses fuel, perhaps with conversion to methanol, ethanol, methane, and/or hydrogen. This could become an attractive solar energy conversion method that recycles atmospheric CO2.
While actions that reduce the impact of climate change, such as the establishment of food reserves and the diversification of agriculture [in individual nations] could be effective, other actions that reduce the rate of production of anthropogenic CO2 depend strongly on multinational cooperation to be effective. If the severe economic and political repercussions that are likely on a world scale are to be avoided, a technological commitment must be made in the next few years at a world strategy found with enlightenment and wisdom. Though humanity may not be able to foresee the conscious consequences of the great experiment clearly enough to control them, we cannot afford not to try.
[Note: CO2 concentration in the atmosphere at Mauna Loa is about 427 ppm as of late June 2024; current anthropogenic production of carbon dioxide is ~50 Gt/yr CO2eq, which is ~13.5 Gt/yr of carbon. Ed.]