Variations of Atmospheric Carbon Dioxide Concentration and Greenhouse Effect at Syowa Station (69o00’S, 39o35’E), Antarctica

On the basis of the analysis of atmospheric carbon dioxide concentration variations and the annual mean air temperature at Syowa Station, Antarctica in the period of 1984-1988, the following results are easily obtained:(1) The annual mean values of the atmospheric carbon dioxide concentration are gradually increased and equal to 342.59, 343.80, 345.15, 346.83 and 348.82 ppmv for 1984, 1985, 1986, 1987 and 1988, respectively. Its annual in-crease rates are 1.21, 1.35, 1.68 and 1.99 ppmv/yr. For 1984-1985, 1985-1986, 1986-1987 and 1987-1988, respectively and are raised year by year.The seasonal variations are observed and the maximum concentration is in spring and the minimum one is in late-summer or early-autumn.(2)The increasing tendency of the concentration of the atmospheric carbon dioxide is consistent with that of the air temperature.     

The carbon isotopic ratio of atmospheric carbon dioxide at Tsukuba,Japan

To find out the secular and seasonal trends of the ¹³C value and CO₂ concentration in the surface air and the determination of the ¹³C in the atmospheric CO₂ collected at Tsukuba Science City was carried out during the period from July 1981 to October 1983. The monthly average of the ¹³C value of CO₂ in the surface air collected at 1400 LMT ranged from -7.52 to \s-8.45 with an average of -7.96±0.25 and the CO₂ concentration in the air varied from 334.5 l 1^-1 to 359 l 1^-1 with an average of 347.2±6.3 l 1^-1. The ¹³C value is high in summer and low in winter and is negatively correlated with the CO₂ concentration. In general, the relationship between the ¹³C and the CO₂ concentration is explainable by a simple mixing model of two different constant carbon isotopic species but the relationship does not always follow the model. The correlation between the ¹³C value and the CO₂ concentration is low during the plant growth season and high at other times. The observed negative deviation of the ¹³C value from the simple mixing model in the plant growth season is partly due to the isotopic fractionation process which takes place in the land biota.     

南极昭和站平流层臭氧变化与NAT凝结温度的关系

根据南极昭和站的臭氧和气象探空资料,分析了昭和站上空平流层内几个等压面（20,30,50,70,100和150 hPa）上臭氧变化与硝酸·三水合物（分子式HNO3·3H2O,记为NAT）凝结温度的关系,给出了臭氧变化的一个基本特征。     

Tropical deforestation and atmospheric carbon dioxide

Recent estimates of the net release of carbon to the atmosphere from deforestation in the tropics have ranged between 0.4 and 2.5 × 10¹⁵ g yr^–1. Two things have happened to require a revision of these estimates. First, refinements of the methods used to estimate the stocks of carbon in the vegetation of tropical forests have produced new estimates that are intermediate between the previous high and low estimates of carbon stocks. When these revised estimates were used here to calculate the emissions of carbon from deforestation, the new range was 1.0–2.0 × 10¹⁵ g C.Second, the previous range of estimates of flux was based on rates of deforestation in 1980. Myers' recent estimate of the rates of tropical deforestation in 1989 is about 90% higher than the rates just 10 years ago. When these recent rates were used to calculate the current net flux of carbon to the atmosphere, the range was between 1.6 and 2.7 × 10¹⁵ g C.Other uncertainties expanded this range, however, to 1.1–3.6 × 10¹⁵ g C yr^–1. Three factors contributed about equally to the expanded range: rates of deforestation, the fate of deforested lands (permanent or temporary clearing), and carbon stocks of forests, including anthropogenic reductions of carbon stocks within forests (thinning or degradation).     

Dynamic responses of atmospheric carbon dioxide concentration to global temperature changes between 1850 and 2010

Changes in Earth's temperature have significant impacts on the global carbon cycle that vary at different time scales, yet to quantify such impacts with a simple scheme is traditionally deemed difficult. Here, we show that, by incorporating a temperature sensitivity parameter(1.64 ppm yr~(-1) ?C~(-1)) into a simple linear carbon-cycle model, we can accurately characterize the dynamic responses of atmospheric carbon dioxide(CO_2) concentration to anthropogenic carbon emissions and global temperature changes between 1850 and 2010(r~2 0.96 and the root-mean-square error 1 ppm for the period from 1960onward). Analytical analysis also indicates that the multiplication of the parameter with the response time of the atmospheric carbon reservoir(～12 year) approximates the long-term temperature sensitivity of global atmospheric CO_2concentration(～15 ppm?C~(-1)), generally consistent with previous estimates based on reconstructed CO_2 and climate records over the Little Ice Age. Our results suggest that recent increases in global surface temperatures, which accelerate the release of carbon from the surface reservoirs into the atmosphere, have partially offset surface carbon uptakes enhanced by the elevated atmospheric CO_2 concentration and slowed the net rate of atmospheric CO_2 sequestration by global land and oceans by ～30%since the 1960 s. The linear modeling framework outlined in this paper thus provides a useful tool to diagnose the observed atmospheric CO_2 dynamics and monitor their future changes.     

The Montsouris series of carbon dioxide concentration measurements, 1877–1910

The longest continuous record of measurements of atmospheric CO₂ concentration available to date, that was made between 1877 and 1910 at the Montsouris Observatory in the outskirts of Paris, is presented and the methods used and the site are described. Annual, seasonal and daily variations in the record were considerable, especially between 1877 and 1880 and possible reasons for this high variability are discussed. Although no direct proof of the reliability of the series is available an attempt has been made to estimate this by comparisons with contemporary series whose precision is better known and also through an analysis of the results from the point of view of the major sources of error. The results suggest a precision of measurement better than 2%; analysis of the daily and the mean seasonal variation shows no evidence of any significant urban contamination of the Montsouris record. Mean decadal values of the Montsouris series show a marked rise in concentration from 283 ppm in the first decade to 313 ppm in the second, with a small and nonsignificant drop to 309 ppm in the third decade of the series. The results of the measurements are thus compatible with the hypothesis that a major and variable non-fossil fuel source of atmospheric CO₂ was active during the last quarter of the nineteenth century. Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel. No. 254-E, 1981 series.     

The atmospheric carbon dioxide response to oceanic primary productivity fluctuations

Data on the rate of primary production, the rate of sinking and oxidation of organic detritus, the rate of regeneration of calcium carbonate, the average rate of vertical mixing, and the vertical profile of dissolved carbon are consistent with a model of the ocean in which the downward transport of carbon by the sinking and oxidation of organic particulate matter is balanced by upward hydrodynamic mixing of dissolved inorganic carbon. A time dependent version of this model is used to make rough estimates of the effect of periodic and impulsive changes in the rate of primary production on the atmospheric CO₂ concentration. The computations suggest that a 1% decrease in marine biospheric productivity could result in a steady state increase of the atmospheric CO₂ concentration of from 0.5 to 2.5% depending on the rate of vertical mixing. Large but short term fluctuations in productivity, such as a die-off of the marine biosphere followed by an exponential recovery period, are estimated to produce smaller perturbations.Work performed under the auspices of the U.S. Department of Energy by the Lawrence Livermore National Laboratory under contract No. W-7405-ENG-48.     

The effects of carbon cycle model error in calculating future atmospheric carbon dioxide levels

Empirical investigations have indicated that projections of future atmospheric carbon dioxide concentrations of a quality quite adequate for practical questions regarding the environmental threat of anthropogenic carbon dioxide emissions and its relationship to energy use policy could be made with the simple assumption that a constant fraction of these emissions would be retained by the atmosphere. By analysis of the structural behavior of equations describing the transfer of carbon and carbon dioxide between their several reservoirs we have been able to demonstrate that this characteristic can be explained to result from approximately linear behavior and exponentially growing carbon dioxide release rates, combined with fitting of carbon cycle model parameters to the last twenty years of observed atmospheric carbon dioxide growth. These conclusions are independent of the details of carbon cycle model structure for projections up to 100 years into the future as long as the growth in atmospheric carbon dioxide release rates is sufficiently high, of the order of 1.5% per annum or more, as referenced to p re-industrial (steady state) conditions. At low rates of growth, when the longer response times of the carbon cycling system become important, for most energy use projections the resultant CO₂ induced climate changes are small and the uncertainties in predicted atmospheric carbon dioxide level are thus not important. A possible exception to this condition occurs for scenarios of future fossil fuel use rates designed to avoid atmospheric CO₂ levels exceeding a chosen threshold. In this instance details of carbon cycle model structure could significantly affect conclusions that might be drawn concerning future energy use policies; however, it is possible that such a result stems from inappropriate specification of a criterion for an environmental threat, rather than from inherent inadequacy of current carbon cycle models. Recent carbon cycle model developments postulate transfer processes of carbon into the deep ocean, large carbon storage reservoir at rates much higher than in the models we have analysed. If the existence of such mechanisms is confirmed, and they are found to be sufficiently rapid and large, some of our conclusions regarding the use of the constant fractional retention assumption may have to be modified. Currently at the Gas Research Institute, 8600 West Bryn, Mawr Ave., Chicago, IL 60631, U.S.A.     

春季南极昭和站上空增温与臭氧含量和分布的关系

本文利用南极昭和站1966—1979年的臭氧和高空气象资料,讨论了春季南极大气爆发性增温及其与臭氧总量、臭氧分压垂直分布的关系,发现如下事实:1.平流层爆发性增温与臭氧总量突变有三种类型,即一次突变型,两次突变型和一次突变与一次缓变混合型;2.平流层爆发性增温3—5天后,对流层上部也有一次剧烈升温;3.增温过程自平流层上部向对流层下传时,伴随着臭氧分压增压中心逐渐向下传递;在平流层各等压面上,臭氧分压变化与气温变化值之间有较好的正相关,相关系数为0.85.     

Climate effects on atmospheric carbon dioxide over the last century

The buildup of atmospheric CO₂ since 1958 is surprisingly well explained by the simple premise that 57% of the industrial emissions (fossil fuel burning and cement manufacture) has remained airborne. This premise accounts well for the rise both before and after 1980 despite a decrease in the growth rate of fossil fuel CO₂ emissions, which occurred at that time, and by itself should have caused the airborne fraction to decrease. In contrast, the buildup prior to 1958 was not simply proportional to cumulative fossil fuel emissions, and notably included a period during the 1940s when CO₂ growth stalled despite continued fossil fuel emissions. Here we show that the constancy of the airborne fraction since 1958 can be in part explained by decadal variations in global land air temperature, which caused a warming-induced release of CO₂ from the land biosphere to the atmosphere. We also show that the 1940s plateau may be related to these decadal temperature variations. Furthermore, we show that there is a close connection between the phenomenology producing CO₂ variability on multidecadal and El Niño timescales.     

Slowing the increase of atmospheric carbon dioxide: A biological approach

Planting trees to act as carbon sinks has been suggested as a way to slow the increase of atmospheric CO₂. Forestry growth and yield models were used to estimate that it would take 192 million hectares of Douglas-fir (Pseudotsuga menziesii) or 250 million hectares of Loblolly pine (Pinus taeda) to capture and store the United States' anthropogenic carbon emissions for an assumed period of 50 yr, at current emission rates. Although maximum growth rates are similar for both species, Douglas-fir requires less area because of its greater ability to store carbon, and its ability to maintain a high growth rate for a longer period of time. The usefulness of a particular species also depends in part on the length of the planning horizon and the forestry project. For periods of 50 or more years, it is important to consider a species' cumulative carbon storage potential rather than its potential maximum growth rate at some point during its life cycle. Forestation (reforestation and afforestation) appears to be feasible as a possible component of a comprehensive strategy for managing the CO₂ problem, but it must be practiced globally to be effective.The research described in this article has been funded by the U.S. Environmental Protection Agency. This document has been prepared at the EPA Environmental Research Laboratory. in Corvallis, Oregon, through contract number 68-C8-0006 to NSI Technology Inc. It has been subjected to the Agency's peer and administrative review and approved for publication. Mention of trade names or commercial products does not constitute endorsement of recommendation for use.