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

Stefan Gerber, Lars O. Hedin, Sonja G. Keel, Stephen Wilson Pacala, Elena Shevliakova

Research output: Contribution to journalArticle

30 Scopus citations

Abstract

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. Key Points Interactions between land-use and CO2 response curtail the land carbon uptake Successional dynamics of land-use recovery affect nitrogen supply and CO2 sink

Original languageEnglish (US)
Pages (from-to)5218-5222
Number of pages5
JournalGeophysical Research Letters
Volume40
Issue number19
DOIs
StatePublished - Oct 16 2013

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Earth and Planetary Sciences(all)

Keywords

  • anthropogenic carbon uptake
  • dynamic vegetation model
  • land use
  • nitrogen limitation
  • residual terrestrial carbon sink

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