Greening of the Earth 1982-2009 revealed by satellite imagery

Trends in LAI from three different sets of satellite imagery
Spatial pattern of trends in greening/browning derived from three satellite remote sensing data sets (a) GIMMS LAI, (b) GLOBMAP LAI and (c) GLASS LAI for the period 1982 to 2009. Regions labeled by black dots indicate trends that are statistically significant.

Long-term satellite leaf area index (LAI) records were used to investigate trends in the greening/browning of the Earth during 1982–2009. The analysis reveals a persistent and widespread increase of greening over 25% to 50% of the global vegetated area, whereas less than 4% of the globe shows browning. Modeling was used to attempt to explain the greening trend in different regions in terms of CO2 fertilization, nitrogen deposition, climate change, and land cover change. It is plausible that CO2 fertilization may be the most important driver of greening in the tropics, whereas climate change is most important in the high latitudes.

Greening of the Earth and its drivers, Zaichun Zhu et al., Nature Climate Change 6, 791–795 (2016) doi:10.1038/nclimate3004