CO2 fluctuations during the last millenium reconstructed by stomatal frequency analysis

Reconstructed CO2 mixing ratios based on stomatal frequency counts on Tsuga heterophylla needles for the time period from 800 AD to 2000 AD. Black line are the means of 3–5 needles per sample, thick white line represents a 3 point moving average. Grey area shows confidence interval of ± 1 RMSE.

Atmospheric CO2 fluctuations during the last millenium reconstructed by stomatal frequency analysis of Tsuga heterophylla needles

by Kouwenberg L. L. R., Wagner R., Kürschner W. M., Visscher H. (2005)

Lenny Kouwenberg, Rike Wagner, Wolfram Kürschner, Henk Visscher,

In Geology 33: 33-36 –


A stomatal frequency record based on buried Tsuga heterophylla needles reveals significant centennial-scale atmospheric CO2 fluctuations during the last millennium.

The record includes four CO2 minima of 260–275 ppmv (ca. A.D. 860 and A.D. 1150, and less prominently, ca. A.D. 1600 and 1800). Alternating CO2maxima of 300–320 ppmv are present at A.D. 1000, A.D. 1300, and ca. A.D. 1700. These CO2 fluctuations parallel global terrestrial air temperature changes, as well as oceanic surface temperature fluctuations in the North Atlantic.

The results obtained in this study corroborate the notion of a continuous coupling of the preindustrial atmospheric CO2 regime and climate.

Published by

Willem Van Cotthem

Honorary Professor of Botany, University of Ghent (Belgium). Scientific Consultant for Desertification and Sustainable Development.

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