Multi vegetation model evaluation of the Green Sahara climate regime

Research output: Contribution to journalArticle

Authors

Colleges, School and Institutes

External organisations

  • BRISTOL UNIVERSITY
  • University of Exeter
  • SHEFFIELD UNIVERSITY

Abstract

During the Quaternary, the Sahara desert was periodically colonized by vegetation, likely because of orbitally induced rainfall increases. However, the estimated hydrological change is not reproduced in climate model simulations, undermining confidence in projections of future rainfall. We evaluated the relationship between the qualitative information on past vegetation coverage and climate for the mid-Holocene using three different dynamic vegetation models. Compared with two available vegetation reconstructions, the models require 500–800 mm of rainfall over 20°–25°N, which is significantly larger than inferred from pollen but largely in agreement with more recent leaf wax biomarker reconstructions. The magnitude of the response also suggests that required rainfall regime of the early to middle Holocene is far from being correctly represented in general circulation models. However, intermodel differences related to moisture stress parameterizations, biases in simulated present-day vegetation, and uncertainties about paleosoil distributions introduce uncertainties, and these are also relevant to Earth system model simulations of African humid periods.

Details

Original languageEnglish
Pages (from-to)6804-6813
Number of pages10
JournalGeophysical Research Letters
Volume44
Issue number13
Early online date4 Jul 2017
Publication statusPublished - 16 Jul 2017

Keywords

  • paleoclimate, vegetation dynamics