Greenness in semi-arid areas across the globe 1981–2007 — an Earth Observing Satellite based analysis of trends and drivers

University of Copenhagen, Geocenter Denmark, University of Maryland, College Park, Goddard Space Flight Center, Council for Scientific and Industrial Research, University of Bonn, ETH Zurich, Centre National de la Recherche Scientifique, Potsdam Institute for Climate Impact Research, Institut de Recherche pour le Développement, Institut Méditerranéen de Biodiversité et d'Ecologie Marine et Continentale, Clark University, University of Virginia, University of Florida, Lund University, Cheikh Anta Diop University, University of Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Agricultural Plant Physiology and Ecology Research Institute, Helmholtz Centre for Environmental Research