Warming-enhanced Plant Growth in the North Since 1980s: A Greener Greenhouse? NASA GSFC Biospheric Sciences Branch 1 Department of Geography, Boston University.

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Warming-enhanced Plant Growth in the North Since 1980s: A Greener Greenhouse? NASA GSFC Biospheric Sciences Branch 1 Department of Geography, Boston University 2 1 Compton J. Tucker and Daniel Slayback 2 Liming Zhou, Robert K. Kaufmann, and Ranga B. Myneni Slide 2 Has Vegetation Responded to Climate Change? Pronounced warming in northern high latitudes Earlier disappearance of snow in spring Increased precipitation in northern high latitudes Increased concentration of atmospheric CO 2 Changes in Climate Increased productivity through: - enhanced photosynthesis - enhanced nutrient availability Changes in Vegetation Slide 3 coolingwarming Overall warming in Eurasia. Lower warming and even cooling in North America Continental Differences in Warming Land surface April-October temperature trends in C/18 yrs between 1982 and 1999 (NASA GISS Station Temperature data) Slide 4 GIMMS NDVI 15-day composite NDVI data at 8 km resolution (07/81-12/99) 1. improved calibration 2. corrections for stratospheric aerosol effects from El Chichon and Mt. Pinatubo eruptions Slide 5 Study Region Vegetated pixels between 30 N-70 N Objectives 1. minimize the effect of Solar Zenith Angle 2. reduce background effects (snow, barren and sparsely vegetated areas) 3. use data from the same pixels in the entire analysis. Slide 6 Changes in Vegetation Activity Changes in vegetation activity can be characterized through 1. changes in growing season 2. changes in seasonal NDVI magnitude Increases in NDVI magnitudeIncreases in growing season JanDecJul Aug Increase NDVI JanDecJul Aug earlier spring delayed fall NDVI Slide 7 Longer Growing Seasons (Increased by 18 Days) (Increased by 12 Days) 11.9 days/18 yrs (p