Soil erosion is unlikely to drive a future carbon sink in Europe

Understanding of the processes governing soil organic carbon turnover is confounded by the fact that C feedbacks driven by soil erosion have not yet been fully explored at large scale.However, in a changing climate, variation in rainfall erosivity (and hence soil erosion)maychange the amount of Cdisplacement, hence inducing feedbacks onto the land C cycle. Using a consistent biogeochemistry-erosionmodel framework to quantify the impact of future climate on the C cycle, we show that C input increases were offset by higher heterotrophic respiration under climate change. Taking into account all the additional feedbacks and C fluxes due to displacement by erosion, we estimated a net source of 0.92 to 10.1 Tg C year−1 from agricultural soils in the European Union to the atmosphere over the period 2016–2100. These ranges represented a weaker and stronger C source compared to a simulation without erosion (1.8 Tg C year−1), respectively, and were dependent on the erosion-driven C loss parameterization, which is still very uncertain. However, when setting a baseline with current erosion rates, the accelerated erosion scenario resulted in 35%more eroded C, but its feedback on the C cycle wasmarginal. Our results challenge the idea that higher erosion driven by climate will lead to a C sink in the near future.

LUGATO Emanuele;  SMITH Pete;  BORRELLI Pasquale;  PANAGOS Panagiotis;  BALLABIO Cristiano;  ORGIAZZI Alberto;  FERNANDEZ UGALDE Oihane;  MONTANARELLA Luca;  JONES Arwyn; 

2018-11-22

AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE

JRC108691

2375-2548 (online),   

http://advances.sciencemag.org/content/4/11/eaau3523,    https://publications.jrc.ec.europa.eu/repository/handle/JRC108691,   

10.1126/sciadv.aau3523 (online),