Showing papers on "Carbon dioxide in Earth's atmosphere published in 1979"
TL;DR: There is no compelling evidence which establishes that the terrestrial biomass has decreased at a rate comparable to that of fossil fuel combustion over the last two decades, as has been recently claimed.
Abstract: The fate of fossil fuel carbon dioxide released into the atmosphere depends on the exchange rates of carbon between the atmosphere and three major carbon reservoirs, namely, the oceans, shallow-water sediments, and the terrestrial biosphere. Various assumptions and models used to estimate the global carbon budget for the last 20 years are reviewed and evaluated. Several versions of recent atmosphere-ocean models appear to give reliable and mutually consistent estimates for carbon dioxide uptake by the oceans. On the other hand, there is no compelling evidence which establishes that the terrestrial biomass has decreased at a rate comparable to that of fossil fuel combustion over the last two decades, as has been recently claimed.
445 citations
TL;DR: In this article, an atmosphere/mixed layer/diffusive deep-ocean model for the carbon cycle is proposed to control atmospheric carbon dioxide accumulation and attendant climate effects from fossil-fuel burning by diverting a fraction of the combustion product and injecting it into the deep ocean, as proposed by Marchetti.
Abstract: The possibility of controlling atmospheric carbon dioxide accumulation and attendant climatic effects from fossil-fuel burning by diverting a fraction of the combustion product and injecting it into the deep-ocean, as proposed by Marchetti, is analyzed using an atmosphere/mixed layer/diffusive deep-ocean model for the carbon cycle. The model includes the nonlinear buffering of CO2 at the air/sea interface, and considers the long term trends associated with consuming an assumed fossil-fuel reserve equivalent to 7.09 × 1015 kg carbon as a logistic function of time as in the projections of Siegenthaler and Oeschger, except that atmospheric carbon dioxide levels are computed for five alternate strategies: (a) 100% injected into atmosphere, (b) 50% injected at oceanic depth of 1500 m and 50% into atmosphere, (c) 50% injected at sea floor (4000 m) and 50% into atmosphere, (d) 100% at 1500 m depth and (e) 100% at sea floor. Since no carbon leaves the system, all runs approached the same post-fossil fuel equilibrium after several thousand years, Ca ∼- 1150 ppm, almost four times the pre-fossil fuel value (∼- 300 ppm). But the ‘transient’ response of these cases showed a marked variation ranging from a peak overshoot value of 2800 ppm in the year 2130 for 100% atmospheric injection to a slight decrease to the pre-fossil fuel 300 ppm lasting till 2300 with a subsequent slow approach to equilibrium for the 100% deep-ocean injection. The implications of these results for an oceanic injection strategy to mitigate the climatic impact of fossil-fuel CO2 is discussed, as are the ingredients of a second generation carbon cycle model for carrying out such forecasts on an engineering design basis.
106 citations
TL;DR: In this paper, a two-dimensional dynamical model of the atmosphere including radiative and photochemical processes is used to calculate the effect of increased CO2 on stratospheric ozone.
Abstract: INCREASED use of fossil fuels1 and deforestation2 have led to enhanced levels of CO2 in the atmosphere with an increase of about 10% since the beginning of this century1. This upward trend is continuing and it has been predicted that the concentration may double in less than 100 years3–5. We describe here a calculation of the subsequent effect of increased CO2 on stratospheric ozone, using a two-dimensional dynamical model of the atmosphere including radiative and photochemical processes.
42 citations
01 Mar 1979
TL;DR: Although the evidence is quite clear that the increase in atmospheric CO/sub 2/ is at least to a large degree a result of fossil fuel burning, and it is equally clear that this increase will result in some change in the global climate, there are quantitative uncertainties that require additional understanding before full assessments can be made as mentioned in this paper.
Abstract: Although the evidence is quite clear that the increase in atmospheric CO/sub 2/ is at least to a large degree a result of fossil fuel burning, and it is equally clear that this increase will result in some change in the global climate, there are quantitative uncertainties that require additional understanding before full assessments can be made There are also quantitative uncertainties regarding the natural carbon cycle, the behavior of the various reservoirs when perturbed by man, the terrestrial biosphere, and the rate at which the oceans can assimilate and store carbon There are uncertainties in regard to the climate change that can result from increased atmospheric CO/sub 2/ Progress in modeling the atmosphere must continue to narrow these uncertainties before the impacts of climate change on man can be adequately determined The future demands for fossil fuels are uncertain The growth of the developing world will be closely linked to fossil energy for the next five to eight decades Only the observed increase in the atmospheric concentration and the present (and recent past) rate of production of CO/sub 2/ from fossil fuels provide data without uncertainties
9 citations
01 Apr 1979
TL;DR: In this paper, the authors address the sources of atmospheric CO/sub 2/ and assess the impact on climate as reflected by the average ground temperature at each latitude of significant increases in atmospheric CO 2.
Abstract: If the current growth rate in the use of fossil fuels continues at 4.3% per year, then the CO/sub 2/ concentration in the atmosphere can be expected to double by about 2035 provided the current partition of CO/sub 2/ between the atmosphere, biosphere, and oceans is maintained as is the current mix of fuels. Slower rates of anticipated growth of energy use lead to a doubling of the carbon content of the atmosphere sometime in the period 2040 to 2060. This report addresses the questions of the sources of atmospheric CO/sub 2/; considers distribution of the present CO/sub 2/ among the atmospheric, oceanic, and biospheric reservoir; and assesses the impact on climate as reflected by the average ground temperature at each latitude of significant increases in atmospheric CO/sub 2/. An analytic model of the atmosphere was constructed (JASON Climate Model). Calculation with this zonally averaged model shows an increase of average surface temperature of 2.4/sup 0/ for a doubling of CO/sub 2/. The equatorial temperature increases by 0.7/sup 0/K, while the poles warm up by 10 to 12/sup 0/K. The warming of climate will not necessarily lead to improved living conditions everywhere. Changes in sea level, in agricultural productivity, andmore » in water availability can be anticipated, but the dimensions of their economic, political, or social consequences can not.« less
7 citations
01 Jan 1979
TL;DR: In this article, a brief discussion of the global nitrogen cycle, manmade perturbations to the cycle are discussed. And the range for a possible increase in atmospheric temperature at the earth's surface due to perturbed nitrous oxide, ammonia, and nitric acid levels is determined to be 0.4 − 1.5 °K.
Abstract: After a brief discussion of the global nitrogen cycle, manmade perturbations to the cycle are discussed. Estimates of various global fluxes of nitrogen are given, in order to show the extent of human intervention. From different atmospheric nitrogen species nitrous oxide must be expected to produce the most pronounced effect on the thermal structure of the earth's atmosphere when the atmospheric mixing ratios are doubled. This effect, however, is still only about 1/4 of that by atmospheric carbon dioxide when its abundance is modified by the same factor. The rise in atmospheric nitrous oxide to be expected due to the predicted increase in the use of industrial fertilizers and fossil fuels is estimated. Based on this estimate, the range for a possible increase in atmospheric temperature at the earth's surface due to perturbed nitrous oxide, ammonia, and nitric acid levels is determined to be 0.4 – 1.5 °K.
5 citations
01 Apr 1979
TL;DR: In this paper, a new model for the mixing of carbon dioxide in the oceans is proposed, explicitly taking into account the flow of colder and/or saltier water to great depths.
Abstract: The questions of the sources of atmospheric carbon dioxide are addressed; distribution of the present carbon dioxide among the atmospheric, oceanic, and biospheric reservoirs is considered; and the impact on climate as reflected by the average ground temperature at each latitude of significant increases in atmospheric carbon dioxide is assessed. A new model for the mixing of carbon dioxide in the oceans is proposed. The proposed model explicitly takes into account the flow of colder and/or saltier water to great depths. We have constructed two models for the case of radiative equilibrium treating the atmosphere as gray and dividing the infrared emission region into nine bands. The gray atmosphere model predicts an increase of average surface temperature of 2.8/sup 0/K for a doubling of CO/sub 2/, a result about a degree less than the nine band model. An analytic model of the atmosphere was constructed (JASON Climate Model). Calculation with this zonally averaged model shows an increase of average surface temperature of 2.4/sup 0/ for a doubling of CO/sub 2/. The equatorial temperature increases by 0.7/sup 0/K while the poles warm up by 10 to 12/sup 0/K. The JASON climate model suffers from a number of fundamental weaknesses. The rolemore » of clouds in determining the albedo is not adequately taken into account nor are the asymmetries between the northern and southern hemisphere. (JGB)« less
1 citations
TL;DR: The atmospheric carbon dioxide content was monitored continuously near Pretoria for 15 months and variations on the timescale of hours, days and seasons were observed and related to source and meteorological parameters.