RECONSTRUCTION OF PAST TERRESTRIAL CARBON STORAGE IN THE NORTHERN-HEMISPHERE FROM THE OSNABRUCK-BIOSPHERE-MODEL AND PALAEODATA

Until now the reconstruction of past carbon storage from data has ofte n been done by using modern carbon databases. The results are Likely a rough approximation of the reality, and can be improved by the use of biosphere models. These models usually need to be parameterized by a large number of environmental inputs, which are often not available fr om palaeodata. The empirical Osnabruck Biosphere Model (OBM) needs as input only 3 environmental parameters, easily derivable from pollen da ta. We adapted it to reconstruct the past terrestrial carbon storage f rom palaeodata. Sensitivity experiments performed by uniformly decreas ing the mean annual temperature, average annual precipitation and/or C O2 concentration suggest that temperature and CO2 concentration affect the carbon storage more than does precipitation. The use of the only palaeodata available at a global scale shows that only a weakening of CO2 fertilization must be invoked to reconstruct the Last Glacial Maxi mum (LGM) carbon storage, which is an intermediate situation between t he no-fertilization effect assumed by previous studies and the fertili zation effect based on modernist empirical equations. The terrestrial carbon storage in the Northern Hemisphere for this period ranged from 910 to 1270 Pg, which represents an increase of 330 to 710 Pg (a plane tary increase of 470 to 1014 Pg from the LGM to the present). This res ult is similar to our previous reconstruction and agrees broadly with the values estimated on the basis of 0.32 parts per thousand change ob tained for global deep ocean delta(13)C.