Increases in terrestrial carbon storage from the Last Glacial Maximum to the present

EVIDENCE from ice cores1 indicates that concentrations of atmospheric carbon dioxide were lower by about 75 p.p.m. during the Last Glacial Maximum (LGM; ∼18,000 years ago) than during the present interglacial (10,000 years ago to the present). The causes of such large changes in atmospheric CO2 remain uncertain. Using a climate model, Prentice and Fung2 have estimated that there was approximately the same amount of carbon in vegetation and soils during the LGM as there was during the present (pre-industrial) interglacial. In contrast, we present here results based on palynological, pedological and sedimentological evidence which indicate that in fact the amount of carbon in vegetation, soils and peatlands may have been smaller during the LGM by ∼1.3x 1012 tonnes. Thus, organic carbon in vegetation and soils has more than doubled (from 0.96 to 2.3 x 1012 tonnes) since the LGM. Oceanic CO2 reservoirs seem to be the only possible source of this large quantity of carbon that has entered the terrestrial biosphere since the LGM (in addition to that which has entered the atmosphere to give the higher interglacial CO2 levels).

[1]  P. W. Frank.  Productivity of World Ecosystems. , 1976 .

[2]  A. Malahoff,et al.  The fate of fossil fuel Co2 in the oceans , 1977 .

[3]  A. G. Douglas.  The Global Carbon Cycle (Scope 13): B. Bolin, E.T. Degens, S. Kempe and P. Ketner (Editors). Wiley, New York, 1979, 491 pp., U.K. £ 17.50, ISBN 0-471-99710-2 , 1981 .

[4]  Wilfred M. Post,et al.  Soil carbon pools and world life zones , 1982, Nature.

[5]  J. Duplessy,et al.  Climatic conditions deduced from a 150-kyr oxygen isotope–pollen record from the Arabian Sea , 1982, Nature.

[6]  P. J. Edwards,et al.  World Forest Biomass and Primary Production Data. , 1983 .

[7]  H. Oeschger,et al.  Ice core sample measurements give atmospheric CO2 content during the past 40,000 yr , 1982, Nature.

[8]  H. E. Wright,et al.  Late Quaternary environments of the Soviet Union , 1985 .

[9]  E. Campo.  Monsoon fluctuations in two 20,000-Yr B.P. Oxygen-isotope/pollen records off southwest India☆ , 1986 .

[10]  H. Delcourt,et al.  Late-Quaternary dynamics of temperate forests: Applications of paleoecology to issues of global environmental change , 1987 .

[11]  P. Colinvaux.  Amazon diversity in light of the paleoecological record , 1987 .

[12]  F. Woodward.  Climate and plant distribution , 1987 .

[13]  C. Villagrán.  Expansion of Magellanic Moorland during the Late Pleistocene: Palynological Evidence from Northern Isla de Chiloé, Chile , 1988, Quaternary Research.

[14]  C. Caratini,et al.  Paleogeographical evolution of the Mahakam delta in Kalimantan, Indonesia during the quaternary and late pliocene , 1988 .

[15]  Kam‐biu Liu.  Quaternary history of the temperate forests of China , 1988 .

[16]  H. Hooghiemstra.  Palynological records from northwest African marine sediments: A general outline of the interpretation of the pollen signal , 1988 .

[17]  J. C. Ritchie,et al.  Postglacial Vegetation of Canada , 1988 .

[18]  G. Hannon,et al.  Vegetational Evidence for Late Quaternary Climatic Changes in Southwest Europe in Relation to the Influence of the North Atlantic Ocean , 1988 .

[19]  A. Lézine.  Late Quaternary Vegetation and Climate of the Sahel , 1989, Quaternary Research.

[20]  Wang Shaoqing,et al.  Studies on quaternary sporo-pollen assemblage and paleoclimate based on Bohai Sea core Bc−1 , 1989 .

[21]  F. Gasse,et al.  The arid–humid transition in the Sahara and the Sahel during the last deglaciation , 1990, Nature.

[22]  H. Faure.  Changes in the global continental reservoir of carbon , 1990 .

[23]  P. Colinvaux,et al.  A pollen record of a complete glacial cycle from lowland Panama , 1990 .

[24]  I. Fung,et al.  The sensitivity of terrestrial carbon storage to climate change , 1990, Nature.