Quantifying the effect of vegetation dynamics on the climate of the Last Glacial Maximum
Article, Other literature type, Research
Jahn , A.
Claussen , M.
Ganopolski , A.
Brovkin , V.
- Publisher: European Geosciences Union (EGU)
(issn: 1814-9332, eissn: 1814-9332)
[ SDU.STU ] Sciences of the Universe [physics]/Earth Sciences | [ SDU.ENVI ] Sciences of the Universe [physics]/Continental interfaces, environment
The importance of the biogeophysical atmosphere-vegetation
feedback in comparison with the radiative effect of lower
atmospheric CO<sub>2</sub> concentrations and the presence of ice sheets
at the last glacial maximum (LGM) is investigated with the climate
system model CLIMBER-2. Equilibrium experiments reveal that most
of the global cooling at the LGM (-5.1°C) relative
to (natural) present-day conditions is caused by the introduction
of ice sheets into the model (-3.0°C), followed by
the effect of lower atmospheric CO<sub>2</sub> levels at the LGM
(-1.5°C), while a synergy between these two factors
appears to be very small on global average. The biogeophysical
effects of changes in vegetation cover are found to cool the global LGM
climate by 0.6°C. The latter are most pronounced in
the northern high latitudes, where the taiga-tundra feedback
causes annually averaged temperature changes of up to
-2.0°C, while the radiative effect of lower
atmospheric CO<sub>2</sub> in this region only produces a cooling of
1.5°C. Hence, in this region, the temperature
changes caused by vegetation dynamics at the LGM exceed the
cooling due to lower atmospheric CO<sub>2</sub> concentrations.