The dominant role of semi-arid ecosystems in the trend and variability of the land CO 2 sink

• DOI: 10.1126/science.aaa1668
• Publication Date: 2015-05-22T21:00:59Z
• Authors: Anders Ahlström; Michael R. Raupach; Guy Schurgers; Benjamin Smith; Almut Arneth; Martin Jung; Markus Reichstein; Josep G. Canadell; Pierre Friedlings...; Atul K. Jain; Etsushi Kato; Benjamin Poulter; Stephen Sitch; Benjamin D. Stocker; Nicolas Viovy; Ying Ping Wang; Andy Wiltshire; Sönke Zaehle; Ning Zeng
• Keywords: Sink (geography); Carbon sink

The difference is found at the margins terrestrial biosphere absorbs about a quarter of all anthropogenic carbon dioxide emissions, but amount that they take up varies from year to year. Why? Combining models and observations, Ahlström et al. marginal ecosystems—semiarid savannas low-latitude shrublands—are responsible for most variability. Biological productivity in these semiarid regions water-limited strongly associated with variations precipitation, unlike wetter tropical areas. Understanding uptake by lands may help improve predictions global cycle. Science , this issue p. 895