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Climate and CO 2 controls on global vegetation distribution at the last glacial maximum: analysis based on palaeovegetation data, biome modelling and palaeoclimate simulations
Author(s) -
HARRISON SANDY P.,
PRENTICE COLIN I.
Publication year - 2003
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1046/j.1365-2486.2003.00640.x
Subject(s) - biome , glacial period , vegetation (pathology) , climatology , last glacial maximum , environmental science , climate change , temperate climate , climate model , tropical vegetation , subtropics , physical geography , boreal , atmospheric sciences , paleoclimatology , geology , tropics , ecosystem , ecology , geography , oceanography , medicine , paleontology , pathology , geomorphology , biology
The global vegetation response to climate and atmospheric CO 2 changes between the last glacial maximum and recent times is examined using an equilibrium vegetation model (BIOME4), driven by output from 17 climate simulations from the Palaeoclimate Modelling Intercomparison Project. Features common to all of the simulations include expansion of treeless vegetation in high northern latitudes; southward displacement and fragmentation of boreal and temperate forests; and expansion of drought‐tolerant biomes in the tropics. These features are broadly consistent with pollen‐based reconstructions of vegetation distribution at the last glacial maximum. Glacial vegetation in high latitudes reflects cold and dry conditions due to the low CO 2 concentration and the presence of large continental ice sheets. The extent of drought‐tolerant vegetation in tropical and subtropical latitudes reflects a generally drier low‐latitude climate. Comparisons of the observations with BIOME4 simulations, with and without consideration of the direct physiological effect of CO 2 concentration on C 3 photosynthesis, suggest an important additional role of low CO 2 concentration in restricting the extent of forests, especially in the tropics. Global forest cover was overestimated by all models when climate change alone was used to drive BIOME4, and estimated more accurately when physiological effects of CO 2 concentration were included. This result suggests that both CO 2 effects and climate effects were important in determining glacial‐interglacial changes in vegetation. More realistic simulations of glacial vegetation and climate will need to take into account the feedback effects of these structural and physiological changes on the climate.