Get access
Geophysical Research Letters

Land use change and nitrogen feedbacks constrain the trajectory of the land carbon sink

Authors

  • Stefan Gerber,

    Corresponding author
    1. Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA
    2. Soil and Water Science Department, IFAS, University of Florida, Gainesville, Florida, USA
    • Corresponding author: S. Gerber, University of Florida, Soil and Water Science Department, IFAS, PO Box 110290, Gainesville, FL 32611, USA. (sgerber@ufl.edu)

    Search for more papers by this author
  • Lars O. Hedin,

    1. Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA
    Search for more papers by this author
  • Sonja G. Keel,

    1. Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA
    2. Climate and Environmental Physics, Physics Institute and Oeschger Centre for Climate Change Research, Bern, Switzerland
    Search for more papers by this author
  • Stephen W. Pacala,

    1. Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA
    Search for more papers by this author
  • Elena Shevliakova

    1. Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA
    Search for more papers by this author

Abstract

[1] Our understanding of Earth's carbon climate system depends critically upon interactions between rising atmospheric CO2, changing land use, and nitrogen limitation on vegetation growth. Using a global land model, we show how these factors interact locally to generate the global land carbon sink over the past 200 years. Nitrogen constraints were alleviated by N2 fixation in the tropics and by atmospheric nitrogen deposition in extratropical regions. Nonlinear interactions between land use change and land carbon and nitrogen cycling originated from three major mechanisms: (i) a sink foregone that would have occurred without land use conversion; (ii) an accelerated response of secondary vegetation to CO2 and nitrogen, and (iii) a compounded clearance loss from deforestation. Over time, these nonlinear effects have become increasingly important and reduce the present-day net carbon sink by ~40% or 0.4 PgC yr−1.

Get access to the full text of this article

Ancillary