This, from A.W. Grabau’s 1913 classic Principles of Stratigraphy:
The chief agents in retaining the sun’s heat within the earth’s atmosphere are the carbon dioxide and the water vapor, which act as thermal blankets. It has been estimated by Arrhenius (2) that if the amount of CO2 in the atmosphere were increased 2.5 to 3 times its present value, the temperature in the arctic regions must rise 8° to 9° C. and produce a climate as mild as that of Eocenic time, so that magnolias would again grow in Greenland. On the other hand, if the CO2, were decreased to an amount ranging from 0.62 to 0.55 of its present value, a fall of from 4° to 5° C. would result and glacial conditions would again overspread the northern parts of the continents. These estimates have been seriously questioned, but the general fact that both CO2 and water vapor act as thermal blankets is established. Chamberlin (13, 14, 15) has discussed in detail the bearing of these facts on former continental glaciation. his argument being that the abstraction of the CO2 from the atmosphere during the periods of extensive vegetal growth, i. e, the periods of coal formation, tended to refrigerate the climate. The amount of CO2 taken from the air in the known geologic periods and locked up in the coals and limestones of the earth has been variously estimated at from 20,000 to 200,000 times the present atmospheric content, or even more. Another factor favoring the consumption of CO2 is the extensive subterranean decomposition of the rocks following a period of elevation with its attendant fissuring of the rock and the deepening of the zone of circulation of surface waters. These, supplied with CO2 at the surface, are active in the carbonation of the decomposing rocks. The solution of limestones and other carbonates is a further source of abstraction of CO2 from the atmosphere, since the original monocarbonates are changed to bicarbonates in the process of solution, the second molecule of CO2 being derived from the atmosphere. This is, however, a temporary abstraction, for on the reposition of the limestone, either by chemical or organic agencies, the second molecule of CO2 is set free again. Hence periods of extensive limestone deposition must be periods of extensive supply of CO2 to the atmosphere, and this would have the effect of ameliorating the climate. It is important to note that extensive coal formation is dependent on the great expanse of land areas, while extensive limestone formation depends on the expanse of the sea. Extension of the land is accompanied further by an extension of the deep-seated circulation, and by decomposition and carbonation of the crystalline rocks, as well as by periods of solution of the carbonates. The two periods of great land expansion, followed by well-authenticated glacial periods, are the close of the Palaeozoic and that of the Cenozoic. Other periods are the pre-Cambric, the close of the Siluric and the opening of the Devonic, the close of the Jurassic and opening of the Comanchic, and the end of the Cretacic. Periods of marine extension, on the other hand, with the formation of much limestone and the accompanying setting free of CO2, were the middle and early upper Ordovicic, the early Siluric (Niagaran), the Mississippic, the upper Jurassic, the mid-Cretacic, and in some regions the Eocenic and Oligocenic. Much evidence exists that these periods of extensive limestone formation were periods of mild and equable climates, very nearly uniform for all latitudes. (pp. 29-30)
There are several interesting takeaways from this:
- Grabau certainly links the increase in CO2 (and water vapour, for that matter) with an increase in global temperature.
- He also thinks that changes in these from purely natural causes took place in the past. He’s also open to the idea that climate in the past may be more desirable than it is now, something that would choke current believers in climate change. He tells us that the setting free of CO2 resulted in “mild and equable climates”.
- There’s none of the dread panic we see these days when considering sea level rise. Seas rise and seas fall; that’s just a reality in the dynamic environment we live in. There are two probable reasons for this apparent nonchalance:
- Populations in those times generally didn’t crowd themselves on the coasts the way they do now (see this relatively recent assessment of the practice).
- The general consensus in those days vis-à-vis science was that problems were made to be solved, not wrung the hands over. The fact that our “scientific” élites are so apocalyptic in their view of life shows that they’re not as scientific as they think.
Everyone these days argues about the “facts” and the “science” but how we view both is just as important. And the latter doesn’t necessarily follow in a straight line from the former, as we see here.