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

The growth rate of atmospheric carbon dioxide (CO2) concentrations since industrialization is characterized by large interannual variability, mostly resulting from variability in CO2 uptake by terrestrial ecosystems (typically termed carbon sink). However, the contributions of regional ecosystems to that variability are not well known. Using an ensemble of ecosystem and land-surface models and an empirical observation-based product of global gross primary production, we show that the mean sink, trend, and interannual variability in CO2 uptake by terrestrial ecosystems are dominated by distinct biogeographic regions. Whereas the mean sink is dominated by highly productive lands (mainly tropical forests), the…

• NS
  National Science Foundation

  Awards: 1129088, AGS 12-43071, AGS-1129088
• UD
  U.S. Department of Energy

  Award: DE-SC0006706
• NA
  National Aeronautics and Space Administration

  Award: NNX14AD94G
• SR
  Sight Research UK

  Award: NE/J010154/1
• CS
  Commonwealth Scientific and Industrial Research Organisation
• MO
  Ministry of Environment
• V
  Vetenskapsrådet

  Award: 637-2014-6895
• KF
  Kungliga Fysiografiska Sällskapet i Lund
• NO
  National Oceanic and Atmospheric Administration

  Awards: NA09NES4400006, NA10OAR4310248
• UG
  U.S. Geological Survey
• SF
  Seventh Framework Programme

  Award: 282672
• NS
  Natural Sciences and Engineering Research Council of Canada
• NE
  Natural Environment Research Council

  Award: NE/J010154/1