Journal cover Journal topic
Climate of the Past An interactive open-access journal of the European Geosciences Union
doi:10.5194/cpd-11-997-2015
© Author(s) 2015. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
30 Mar 2015
Review status
This discussion paper has been under review for the journal Climate of the Past (CP). The revised manuscript was not accepted.
Radiative forcing by forest and subsequent feedbacks in the early Eocene climate
U. Port1, M. Claussen1,2, and V. Brovkin1 1Max Planck Institute for Meteorology, Hamburg 20146, Germany
2Meteorological Institute, University of Hamburg, Hamburg 20146, Germany
Abstract. Using the Max Planck Institute for Meteorology Earth System Model, we investigate the forcing of forests and the feedback triggered by forests in the pre-industrial climate and in the early Eocene climate (about 54 to 52 million years ago). Other than the interglacial, pre-industrial climate, the early Eocene climate was characterised by high temperatures which led to almost ice-free poles. We compare simulations in which all continents are covered either by dense forest or by bare soil. To isolate the effect of soil albedo, we choose either bright soils or dark soils, respectively. Considering bright soil, forests warm in both, the early Eocene climate and the current climate, but the warming differs due to differences in climate feedbacks. The lapse-rate and water-vapour feedback is stronger in early Eocene climate than in current climate, but strong and negative cloud feedbacks and cloud masking in the early Eocene climate outweigh the stronger positive lapse-rate and water-vapour feedback. In the sum, global mean warming is weaker in the early Eocene climate. Sea-ice related feedbacks are weak in the almost ice-free climate of the early Eocene leading to a weak polar amplification. Considering dark soil, our results change. Forests cools stronger in the early Eocene climate than in the current climate because the lapse-rate and water-vapour feedback is stronger in the early Eocene climate while cloud feedbacks and cloud masking are equally strong in both climates. The different temperature change by forest in both climates highlights the state-dependency of vegetation's impact on climate.

Citation: Port, U., Claussen, M., and Brovkin, V.: Radiative forcing by forest and subsequent feedbacks in the early Eocene climate, Clim. Past Discuss., 11, 997-1029, doi:10.5194/cpd-11-997-2015, 2015.
U. Port et al.
U. Port et al.
U. Port et al.

Viewed

Total article views: 572 (including HTML, PDF, and XML)

HTML PDF XML Total BibTeX EndNote
286 241 45 572 14 41

Views and downloads (calculated since 30 Mar 2015)

Cumulative views and downloads (calculated since 30 Mar 2015)

Saved

Discussed

Latest update: 28 Apr 2017
Publications Copernicus
Download
Share