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) may change the amount of C displacement, hence inducing feedbacks onto the land C cycle. Using a consistent biogeochemistry-erosion model 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 was marginal. Our results challenge the idea that higher erosion driven by climate will lead to a C sink in the near future.
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机译：由于尚未充分探索由土壤侵蚀驱动的碳反馈，因此混淆了控制土壤有机碳周转的过程。但是，在气候变化的情况下，降雨侵蚀力的变化（以及土壤侵蚀）的变化可能会改变碳排量，从而引起对土地碳循环的反馈。使用一致的生物地球化学-侵蚀模型框架来量化未来气候对碳循环的影响，我们表明在气候变化下，碳输入增加被较高的异养呼吸所抵消。考虑到所有因腐蚀位移而产生的额外反馈和碳通量，我们估计在此期间从欧盟农业土壤到大气的净源为0.92至10.1 Tg C year −1 2016–2100。与没有腐蚀的模拟（1.8 Tg C year -1 ）相比，这些范围分别代表了更弱和更强的碳源，并且取决于腐蚀驱动的碳损失参数化，这仍然非常不确定。但是，当用当前的腐蚀速率作为基准时，加速腐蚀的情景导致了C侵蚀的35％，但是其对C循环的反馈是微不足道的。我们的结果对以下观点提出了挑战：气候驱动的更高侵蚀将在不久的将来导致碳汇。
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