RESEARCH: OUTCOMES, VIEWPOINTS & PERSPECTIVES

Holocene global dynamics of the carbon cycle

Fire regimes have changed during the Holocene due to changes in climate and in human practices. Here, we hypothesise that changes in fire regime may have affected the global CO₂ concentration in the atmosphere through the Holocene. Our data are based on quantitative reconstructions of biomass burning deduced from stratified charcoal from Europe, and South-, Central- and North America, and Oceania to test the fire-carbon release hypothesis. In Europe the significant increase of fire activity is dated ca. 6000 cal. years ago. In north-eastern North America burning activity was greatest before 7500 years ago, very low between 7500-3000 years, and has been increasing since 3000 years ago. In tropical America, the pattern is more complex and apparently zonal. Maximum burning occurred in the southern Amazon basin and in Central America during the middle Holocene, and during the last 2000 years in the northern Amazon basin. In Oceania, biomass burning has regularly decreased since a maximum 5000 years ago. Biomass burning has broadly increased in the Northern and Southern Hemispheres throughout the second half of the Holocene associated with changes in climate and human practices. Global fire indexes parallel the increase of atmospheric CO₂ concentration recorded in Antarctic ice cores. Future issues on carbon dynamics relatively to biomass burning are discussed to improve the quantitative reconstructions.

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CARCAILLET, C., ALMQUIST, H., ASNONG, H., BRADSHAW, R.H.W., CARRIÓN, J.S., GAJEWSKI, K., HAAS, J.N., HABERLE, S.G., HADORN, P., RICHARD, P.J.H., RICHOZ, I., SÁNCHEZ-GOÑI, M.F., VON STEDINGK, H., STEVENSON, A.C., TALON, B., TINNER, W., TRYTERUD, E., WICK, L. & WILLIS, K.J. 2002. Holocene biomass burning and global dynamics of the carbon-cycle. Chemosphere 49: 845-863