Large influence of soil moisture on long-term terrestrial carbon uptake
By Julia K Green, Sonia I. Seneviratne, A. Berg, K. Findell, Stefan Hagemann, D. Lawrence, Pierre Gentine. Nature, 2019
655 citations recorded by the source corpus.
Although the terrestrial biosphere absorbs about 25 per cent of anthropogenic carbon dioxide (CO2) emissions, the rate of land carbon uptake remains highly uncertain, leading to uncertainties in climate projections1,2. Understanding the factors that limit or drive land carbon storage is therefore important for improving climate predictions. One potential limiting factor for land carbon uptake is soil moisture, which can reduce gross primary production through ecosystem water stress3,4, cause vegetation mortality5 and further exacerbate climate extremes due to land–atmosphere feedbacks6. Previous work has explored the impact of soil-moisture availability on past carbon-flux variability3,7,8. However, the influence of soil-moisture variability and trends on the long-term carbon sink and the mechanisms responsible for associated carbon losses remain uncertain. Here we use the data output from four Earth system models9 from a series of experiments to analyse the responses of terrestrial net biome productivity to soil-moisture changes, and find that soil-moisture variability and trends induce large CO2 fluxes (about two to three gigatons of carbon per year; comparable with the land carbon sink itself1) throughout the twenty-first century. Subseasonal and interannual soil-moisture variability generate CO2 as a result of the nonlinear response of photosynthesis and net ecosystem exchange to soil-water availability and of the increased temperature and vapour pressure deficit caused by land–atmosphere interactions. Soil-moisture variability reduces the present land carbon sink, and its increase and drying trends in several regions are expected to reduce it further. Our results emphasize that the capacity of continents to act as a future carbon sink critically depends on the nonlinear response of carbon fluxes to soil moisture and on land–atmosphere interactions. This suggests that the increasing trend in carbon uptake rate may not be sustained past the middle of the century and could result in accelerated atmospheric CO2 growth. Earth system models suggest that soil-moisture variability and trends will induce large carbon releases throughout the twenty-first century.
Subfields: Global and Planetary Change
View Paper: https://www.semanticscholar.org/paper/55bf4589d73c07e20c567e815498a5bce1afe9e1
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In Global and Planetary Change
Citations in the corpus
- Coupling between the terrestrial carbon and water cycles—a review (2019, background): “…heat waves, have now clearly been identified as key components of the terrestrial water and carbon cycles (Knapp et al 2008, Jaeger and Seneviratne 2010, Reichstein et al 2013, Zscheischler et al 2014, Sippel et al 2017, Vogel et al 2017, von Buttlar et al 2018, Yin et al 2018, Green et al 2019).”
- Just transition on the ground: Challenges and opportunities for social dialogue (2020, background): “automobile industry, climate change, coal, Europe, just transition, unions Introduction: framing the climate emergency context Scientific evidence is piling up: time is running short for having a realistic chance to bring climate change under control (Green et al., 2019).”