Effects of climate extremes on the terrestrial carbon cycle: concepts, processes and potential future impacts.
Extreme droughts, heat waves, frosts, precipitation, wind storms and other climate extremes may impact the structure, composition and functioning of terrestrial ecosystems, and thus carbon cycling and its feedbacks to the climate system. Yet, the interconnected avenues through which climate extremes drive ecological and physiological processes and alter the carbon balance are poorly understood. Here, we review the literature on carbon cycle relevant responses of ecosystems to extreme climatic events. Given that impacts of climate extremes are considered disturbances, we assume the respective general disturbance-induced mechanisms and processes to also operate in an extreme context. The paucity of well-defined studies currently renders a quantitative meta-analysis impossible, but permits us to develop a deductive framework for identifying the main mechanisms (and coupling thereof) through which climate extremes may act on the carbon cycle. We find that ecosystem responses can exceed the duration of the climate impacts via lagged effects on the carbon cycle. The expected regional impacts of future climate extremes will depend on changes in the probability and severity of their occurrence, on the compound effects and timing of different climate extremes, and on the vulnerability of each land-cover type modulated by management. Although processes and sensitivities differ among biomes, based on expert opinion, we expect forests to exhibit the largest net effect of extremes due to their large carbon pools and fluxes, potentially large indirect and lagged impacts, and long recovery time to regain previous stocks. At the global scale, we presume that droughts have the strongest and most widespread effects on terrestrial carbon cycling. Comparing impacts of climate extremes identified via remote sensing vs. ground-based observational case studies reveals that many regions in the (sub-)tropics are understudied. Hence, regional investigations are needed to allow a global upscaling of the impacts of climate extremes on global carbon-climate feedbacks.
Max Planck Institute for Biogeochemistry, 07745, Jena, Germany.
Dorothea
D
Frank
Max Planck Institute for Biogeochemistry, 07745, Jena, Germany.
Markus
M
Reichstein
Institute of Ecology, University of Innsbruck, 6020, Innsbruck, Austria.
Michael
M
Bahn
Potsdam Institute for Climate Impact Research (PIK) e.V., 14773, Potsdam, Germany.|Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), 14195, Berlin, Germany.
Kirsten
http://orcid.org/0000-0001-5283-4937
K
Thonicke
Swiss Federal Research Institute WSL, 8903, Birmensdorf, Switzerland.|Oeschger Centre for Climate Change Research, University of Bern, CH-3012, Bern, Switzerland.
David
D
Frank
Max Planck Institute for Biogeochemistry, 07745, Jena, Germany.
Miguel D
MD
Mahecha
Institute of Biological and Environmental Sciences, University of Aberdeen, 23 St Machar Drive, Aberdeen, AB24 3UU, UK.
Pete
P
Smith
Ecosystems Services and Management Program, International Institute of Applied Systems Analysis (IIASA), A-2361, Laxenburg, Austria.
Marijn
M
van der Velde
Research Group of Plant and Vegetation Ecology, Biology Department, University of Antwerp, Wilrijk, Belgium.
Sara
S
Vicca
Potsdam Institute for Climate Impact Research (PIK) e.V., 14773, Potsdam, Germany.|Laboratory of Tree-Ring Research, The University of Arizona, 1215 E Lowell St, Tucson, AZ, 85721, USA.
Flurin
F
Babst
Max Planck Institute for Biogeochemistry, 07745, Jena, Germany.|Department of Environmental Science and Analytical Chemistry (ACES), Bolin Centre for Climate Research, Stockholm University, 10691, Stockholm, Sweden.
Christian
C
Beer
ETH Zurich, 8092, Zurich, Switzerland.
Nina
N
Buchmann
Global Carbon Project, CSIRO Oceans and Atmosphere Flagship, GPO Box 3023, Canberra, ACT, 2601, Australia.
Josep G
JG
Canadell
IPSL - Laboratoire des Sciences du Climat et de l'Environnement CEA-CNRS-UVSQ, 91191, Gif sur Yvette, France.
Philippe
P
Ciais
Institut Méditerranéen de Biodiversité et d'Ecologie marine et continentale (IMBE), Aix Marseille Université, CNRS, IRD, Avignon Université, Aix-en-Provence, France.
Wolfgang
http://orcid.org/0000-0002-9205-5812
W
Cramer
Department of Chemical and Biochemical Engineering, Technical University of Denmark (DTU), Frederiksborgvej 399, 4000, Roskilde, Denmark.
Andreas
A
Ibrom
IBIMET-CNR, Via Caproni, 8, 50145, Firenze, Italy.|FoxLab, Fondazione E.Mach, Via Mach 1, 30158, San Michele a/Adige, Trento, Italy.
Franco
F
Miglietta
IPSL - Laboratoire des Sciences du Climat et de l'Environnement CEA-CNRS-UVSQ, 91191, Gif sur Yvette, France.
Ben
B
Poulter
Oeschger Centre for Climate Change Research, University of Bern, CH-3012, Bern, Switzerland.|Institute of Biological and Environmental Sciences, University of Aberdeen, 23 St Machar Drive, Aberdeen, AB24 3UU, UK.
Anja
A
Rammig
ETH Zurich, 8092, Zurich, Switzerland.
Sonia I
SI
Seneviratne
Institute of Earth and Environmental Science, University of Potsdam, 14476, Potsdam, Germany.
Ariane
A
Walz
Helmholtz Centre Potsdam, GFZ German Research Centre For Geosciences, 14473, Potsdam, Germany.
Martin
http://orcid.org/0000-0002-1843-1031
M
Wattenbach
Forest Ecology and Restoration Group, Universidad de Alcalá, Alcalá de Henares, Madrid, Spain.
Miguel A
MA
Zavala
Max Planck Institute for Biogeochemistry, 07745, Jena, Germany.
Jakob
J
Zscheischler
D057486:Carbon Cycle; D057231:Climate Change; D017753:Ecosystem
carbon cycle; climate change; climate extremes; climate variability; disturbance; terrestrial ecosystems