Warming-related increases in soil CO2 efflux are explained by increased below-ground carbon flux

Christian P. Giardina, Creighton M. Litton, Susan E. Crow, Gregory P. Asner

Research output: Contribution to journalArticle

89 Scopus citations

Abstract

The universally observed exponential increase in soil-surface CO 2 efflux ('soil respiration'; F S) with increasing temperature has led to speculation that global warming will accelerate soil-organic-carbon (SOC) decomposition, reduce SOC storage, and drive a positive feedback to future warming. However, interpreting temperature-F S relationships, and so modelling terrestrial carbon balance in a warmer world, is complicated by the many sources of respired carbon that contribute to F S (ref.) and a poor understanding of how temperature influences SOC decomposition rates. Here we quantified F S, litterfall, bulk SOC and SOC fraction size and turnover, and total below-ground carbon flux (TBCF) across a highly constrained 5.2 °C mean annual temperature (MAT) gradient in tropical montane wet forest. From these, we determined that: increases in TBCF and litterfall explain >90% of the increase in F S with MAT; bulk SOC and SOC fraction size and turnover rate do not vary with MAT; and increases in TBCF and litterfall do not influence SOC storage or turnover on century to millennial timescales. This gradient study shows that for tropical montane wet forest, long-term and whole-ecosystem warming accelerates below-ground carbon processes with no apparent impact on SOC storage.

Original languageEnglish (US)
Pages (from-to)822-827
Number of pages6
JournalNature Climate Change
Volume4
Issue number9
DOIs
StatePublished - Sep 11 2014
Externally publishedYes

ASJC Scopus subject areas

  • Environmental Science (miscellaneous)
  • Social Sciences (miscellaneous)

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