Changes in the Carbon Content of Terrestrial Biota and Soils between 1860 and 1980: A Net Release of CO"2 to the Atmosphere

Changes in land use over the past two centuries have caused a significant release of CO2 to the atmosphere from the terrestrial biota and soils. An analysis of this release is based on amounts of organic carbon within an ecosystem following changes such as harvest of forests; it is also based on rates of changes, such as conversion of forest to agriculture, deduced from agricultural and forestry statistics. A model is used to calculate the net amount of carbon stored or released each year by the biota and soils of 69 regional ecosystems. Some of the changes, such as afforestation, the growth of harvested forests, and buildup of soil organic matter, result in a storage of carbon; others, such as harvest of forests and increase in pasture and agricultural areas, result in a loss of carbon to the atmosphere. According to this analysis, there has been a net release of carbon from terrestrial ecosystems worldwide since at least 1860. Until 1960, the annual release was greater than release of carbon from fossil fuels. The total net release of carbon from terrestrial ecosystems since 1860 is estimated to have been 180 x 1015 g (a range of estimates is 135-228 x 1015 g). The estimated net release of carbon in 1980 was 1.8-4.7 x 1015 g; for the 22 yr since 1958 the release of C was 38-76 x 1015 g. The ranges reflect the differences among various estimates of forest biomass, soil carbon, and agricultural clear- ing. Improvements in the data on the clearing of tropical forests alone would reduce the range of estimates for 1980 by almost 60%. Estimates of the other major terms in the global carbon budget, the atmospheric increase in C02, the fossil fuel release of C02, and the oceanic uptake of C02, are all subject to uncertainties. The combined errors in these estimates are large enough that the global carbon budget appears balanced if the low estimate for the biotic release of carbon given above is used (1.8 x 1015 g released in 1980) with the higher estimates of oceanic uptake. If higher estimates for biotic release are used, then the carbon budget does not balance, and the estimates of oceanic uptake or of other factors require revision.

[1]  George M. Woodwell,et al.  The role of terrestrial vegetation in the global carbon cycle : measurement by remote sensing , 1985 .

[2]  T. Barr.  The world food situation and global grain prospects. , 1981, Science.

[3]  L. Brown.  World population growth, soil erosion, and food security. , 1981, Science.

[4]  S. V. Smith.  Marine macrophytes as a global carbon sink. , 1981, Science.

[5]  A. O. Aweto.  Organic Matter Build-Up in Fallow Soil in a Part of South-Western Nigeria and its Effects on Soil Properties , 1981 .

[6]  T. Armentano.  Drainage of Organic Soils as a Factor in the World Carbon Cycle , 1980 .

[7]  H. Delcourt,et al.  Carbon Budget of the Southeastern U.S. Biota: Analysis of Historical Change in Trend from Source to Sink , 1980, Science.

[8]  P. Crutzen,et al.  Estimates of gross and net fluxes of carbon between the biosphere and the atmosphere from biomass burning , 1980 .

[9]  R. E. Phillips,et al.  No-Tillage Agriculture , 1980, Science.

[10]  P. Tans,et al.  Past atmospheric CO2 levels and the 13C/12C ratios in tree rings , 1980 .

[11]  R. Stallard,et al.  Organic Carbon: Oxidation and Transport in the Amazon River , 1980, Science.

[12]  T. Armentano,et al.  The role of temperate zone forests in the global carbon cycle , 1980 .

[13]  S. Manabe,et al.  On the Distribution of Climate Change Resulting from an Increase in CO2 Content of the Atmosphere , 1980 .

[14]  A. Lugo,et al.  Tropical forest ecosystems: sources or sinks of atmospheric carbon? , 1980 .

[15]  A. Lugo,et al.  Preliminary estimate of the storage of organic carbon in tropical forest ecosystems. , 1980 .

[16]  F. Millero,et al.  Gradual increase of oceanic CO2 , 1979, Nature.

[17]  W. Broecker,et al.  Fate of Fossil Fuel Carbon Dioxide and the Global Carbon Budget , 1979, Science.

[18]  Marion Clawson,et al.  Forests in the Long Sweep of American History , 1979, Science.

[19]  M. J. Salinger.  New Zealand climate: The temperature record, historical data and some agricultural implications , 1979 .

[20]  P. Sánchez,et al.  Seminar on Pasture Production in Acid Soils of the Tropics (1978, Cali, Colombia). Pasture production in acid soils of the tropics : Proceedings , 1979 .

[21]  U. Hampicke.  Man'S Impact on the Earth'S Vegetation Cover and Its Effects On Carbon Cycle and Climate , 1979 .

[22]  P. Brewer.  Direct observation of the oceanic CO2 increase , 1978 .

[23]  K. Wagener.  Total anthropogenic CO2 production during the period 1800–1935 from carbon-13 measurements in tree rings , 1978, Radiation and environmental biophysics.

[24]  J. Olson,et al.  Changes in the global carbon cycle and the biosphere , 1978 .

[25]  A. T. Wilson.  Pioneer agriculture explosion and CO2 levels in the atmosphere , 1978, Nature.

[26]  C. S. Wong.  Atmospheric Input of Carbon Dioxide from Burning Wood , 1978, Science.

[27]  H. Oeschger,et al.  Predicting future atmospheric carbon dioxide levels. , 1978, Science.

[28]  M. Stuiver.  Atmospheric Carbon Dioxide and Carbon Reservoir Changes , 1978, Science.

[29]  G. Likens,et al.  The biota and the world carbon budget. , 1978, Science.

[30]  P. Tans.  Carbon 13 and carbon 14 in trees and the atmospheric CO2 increase , 1978 .

[31]  J. Arnold,et al.  Fuelwood and charcoal in developing countries. An economic survey. , 1978 .

[32]  Patrick Fleuret,et al.  Fuelwood Use in a Peasant Community: A Tanzanian Case Study , 1978 .

[33]  H. Freyer.  PRELIMINARY EVALUATION OF PAST CO2 INCREASE AS DERIVED FROM 13C MEASUREMENTS IN TREE RINGS , 1978 .

[34]  M. Heimann,et al.  Model responses of the atmospheric CO2 level and 13C/12C ratio to biogenic CO2 input , 1978 .

[35]  E. Eckholm,et al.  Spreading Deserts--The Hand of Man. , 1977 .

[36]  B. Bolin,et al.  Changes of land biota and their importance for the carbon cycle. , 1977, Science.

[37]  J. Adams,et al.  Wood Versus Fossil Fuel as a Source of Excess Carbon Dioxide in the Atmosphere: A Preliminary Report , 1977, Science.

[38]  W. Clarke.  Maintenance of agriculture and human habitats within the tropical forest ecosystem , 1976 .

[39]  Broadus Mitchell,et al.  European Historical Statistics, 1750-1970. , 1976 .

[40]  H. Oeschger,et al.  A box diffusion model to study the carbon dioxide exchange in nature , 1975 .

[41]  A. N. Duckham,et al.  The Agricultural Systems of the World: An Evolutionary Approach. , 1974 .

[42]  R. Persson.  World forest resources : review of the world's forest resources in the early 1970's , 1974 .

[43]  L. Machta.  Prediction of CO2 in the atmosphere. , 1973, Brookhaven symposia in biology.

[44]  R. Bacastow,et al.  Atmospheric carbon dioxide and radiocarbon in the natural carbon cycle: II. Changes from A. D. 1700 to 2070 as deduced from a geochemical model. , 1973, Brookhaven symposia in biology.

[45]  G. Likens,et al.  Carbon in the biota. , 1973, Brookhaven symposia in biology.

[46]  C. D. Keeling.  The Carbon Dioxide Cycle: Reservoir Models to Depict the Exchange of Atmospheric Carbon Dioxide with the Oceans and Land Plants , 1973 .

[47]  D. John.  Accumulation and decay of litter and net production of forest in tropical West Africa , 1973 .

[48]  M. Witkamp.  Soils as components of ecosystems , 1971 .

[49]  C. D. Keeling,et al.  The concentration of atmospheric carbon dioxide in Hawaii , 1965 .

[50]  R. Cunningham.  THE EFFECT OF CLEARING A TROPICAL FOREST SOIL , 1963 .

[51]  C. Kellogg.  The Soil under Shifting Cultivation , 1962 .

[52]  G. Hart.  Humus depths under cut and uncut northern hardwood forests , 1960 .

[53]  J. Giddens.  Rate of Loss of Carbon from Georgia Soils , 1957 .

[54]  C. E. Evans,et al.  Nitrogen and carbon changes in great plains soils as influenced by cropping and soil treatments , 1957 .

[55]  C. J. Robertson.  The expansion of the arable area , 1956 .

[56]  H. Lull,et al.  The role of forest humus in watershed management in New England , 1956 .

[57]  R. S. Sartz,et al.  Some factors affecting humus development in the Northeast. , 1950 .

[58]  Raphael Zon,et al.  Forest Resources of the World. , 1911 .