Ecophysiological implications of projected changes in climate in the 21st century: variability in vegetation water use efficiency and productivity in a CMIP5 multimodel ensemble

Sergio Bernardes, NASA, sbernard@uga.edu (Presenter)
Elizabeth M. Middleton, NASA GSFC, elizabeth.m.middleton@nasa.gov
Petya Krasteva Entcheva Campbell, NASA GSFC/JCET/UMBC, petya.campbell@nasa.gov
Karl Fred Huemmrich, NASA GSFC/UMBC, karl.f.huemmrich@nasa.gov
Qingyuan Zhang, GESTAR/USRA, qingyuan.zhang-1@nasa.gov
Lawrence A Corp, SSAI, lawrence.a.corp@nasa.gov
David Landis, SSAI, david.r.landis@nasa.gov

Climate projections for the 21st century predict substantial changes in temperature and in the quantity and spatiotemporal distribution of precipitation for large regions on the planet. Vegetation is expected to respond to this climatic variability, particularly when associated with reductions in water availability resulting from decreased precipitation and increased water demand by the atmosphere. These conditions have been demonstrated to negatively affect plant metabolism, reduce primary productivity/carbon uptake, affect plant survival, change fire regimes, and limit services of entire ecosystems. In contrast, it has been reported that future increases in temperature and in atmospheric carbon dioxide concentrations may help offset some of these impacts on vegetation. In particular, plants may adjust their water use efficiency (WUE, plant production per water loss by evapotranspiration) in response to changing environmental conditions. This investigation assesses an ensemble of models from the fifth phase of the Coupled Model Intercomparison Project (CMIP5) and analyzes changes in climate variables, primary productivity and WUE, predicted to occur in the 21st century. The analysis uses outputs from eight CMIP5 models, encompassing multiple implementations of dynamic vegetation, nitrogen cycle and land use and land cover change. The work considers two representative concentration pathways (RCP4.5 and RCP8.5) for the period 2006-2100 and compares projections to historical data (1850–2005). Results include global, regional and latitudinal distributions of model outputs for both carbon dioxide scenarios, considering also comparisons between historical and projected conditions. We observed significant intramodel variability when representing changes in WUE over the 21st century, including high model sensitivity to different atmospheric carbon concentration scenarios. Higher changes in WUE were observed for RCP8.5 in most of the models considered. A global analysis of the spatial distribution of WUE changes is presented for multiple models and the representative concentration pathways.

Presentation Type:  Poster

Session:  Theme 4: Human influence on global ecosystems   (Mon 4:30 PM)

Associated Project(s): 

• Middleton, Betsy: Spectral Bio-Indicators of Ecosystem Photosynthetic Efficiency II: Synthesis and Integration ...details

Poster Location ID: 23