Carbon cycle. The dominant role of semi-arid ecosystems in the trend and variability of the land CO₂ sink

Science. 2015 May 22;348(6237):895-9. doi: 10.1126/science.aaa1668. Epub 2015 May 21.

Authors

Anders Ahlström¹, Michael R Raupach², Guy Schurgers³, Benjamin Smith⁴, Almut Arneth⁵, Martin Jung⁶, Markus Reichstein⁶, Josep G Canadell⁷, Pierre Friedlingstein⁸, Atul K Jain⁹, Etsushi Kato¹⁰, Benjamin Poulter¹¹, Stephen Sitch¹², Benjamin D Stocker¹³, Nicolas Viovy¹⁴, Ying Ping Wang¹⁵, Andy Wiltshire¹⁶, Sönke Zaehle⁶, Ning Zeng¹⁷

Affiliations

¹ Department of Physical Geography and Ecosystem Science, Lund University, 223 62 Lund, Sweden. Department of Earth System Science, School of Earth, Energy and Environmental Sciences, Stanford University, Stanford, CA 94305, USA. anders.ahlstrom@nateko.lu.se.
² Climate Change Institute, Australian National University, Canberra, ACT 0200, Australia.
³ Department of Geosciences and Natural Resource Management, University of Copenhagen, 1350 Copenhagen, Denmark.
⁴ Department of Physical Geography and Ecosystem Science, Lund University, 223 62 Lund, Sweden.
⁵ Institute for Meteorology and Climate Research-Atmospheric Environmental Research, Karlsruhe Institute for Technology, 82476 Garmisch-Partenkirchen, Germany.
⁶ Biogeochemical Intergration Department, Max Planck Institute for Biogeochemistry, 07745 Jena, Germany.
⁷ Global Carbon Project, CSIRO Oceans and Atmospheric Flagship, Canberra, ACT, Australia.
⁸ College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter EX4 4QF, UK.
⁹ Department of Atmospheric Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
¹⁰ Institute of Applied Energy, 105-0003 Tokyo, Japan.
¹¹ Institute on Ecosystems and the Department of Ecology, Montana State University, Bozeman, MT 59717, USA.
¹² College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4RJ, UK.
¹³ Department of Life Sciences, Imperial College, Ascot SL5 7PY, UK. Climate and Environmental Physics, Physics Institute and Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland.
¹⁴ Laboratoire des sciences du climat et de l'environnement, CEA Saclay, F-91191 Gif-sur-Yvette Cedex, France.
¹⁵ CSIRO Ocean and Atmosphere Flagship, PMB 1, Aspendale, Victoria 3195, Australia.
¹⁶ Met Office Hadley Centre, Fitzroy Road, Exeter EX1 3PB, UK.
¹⁷ Department of Atmospheric and Oceanic Science and Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD 20742, USA.

PMID: 25999504
DOI: 10.1126/science.aaa1668

Abstract

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 trend and interannual variability of the sink are dominated by semi-arid ecosystems whose carbon balance is strongly associated with circulation-driven variations in both precipitation and temperature.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Atmosphere / chemistry*
Carbon Cycle*
Carbon Dioxide / analysis*
Forests*
Grassland*

Substances

Carbon Dioxide