Although forest removal has been well documented at a global level, knowledge of how major forest processes such as photosynthesis have been affected remains poor. Global forest change between 1986 and 1993 was assessed using the NOAA/AVHRR satellite data converted to terrestrial net primary productivity (NPP). Forest loss was a dominant feature in tropical regions, with the most severe destruction in Latin America followed by southeast Asia and Africa. Loss of high-productivity forests over wide areas was observed for countries such as Brazil and Bolivia. Further analysis showed that approximately 12% (9100999 km2) and 19% (2 600000 km2) of the low-NPP regions (<500 g m−2yr−1, e.g., deserts, tundra) and the high-NPP regions (> 2000 g m−2yr−1, e.g., tropical rain forests), respectively, were transformed to intermediate-NPP regions (500–1500 g m−2yr−1, e.g., savanna, grassland, or cultivated land), between 1986 and 1993. The extent of global forest degradation or fragmentation may be more severe than the deforestation itself. Low-latitude ecosystems were more prone to decline in NPP than mid- and high-latitude ecosystems. The NPP method offers insight into global forest change in a timely, practical and consistent manner.