Finding the sweet scale to understand processes and climate control over soil carbon stocks

Earth system model are designed to capture our present knowledge of soil-carbon-climate interactions. However, uncertainties remain high because mechanistic insights are available at fine scales for which we can never achieve unbiased resolution for global modeling. Consequently, the key challenge gaining global or regional overviews of soil carbon-climate feedbacks is to identify the scale that best reflects the underlying soil processes without getting lost in details. According to latest findings, the dominant control of soil carbon persistence varies with climate, which suggests that overarching proxies at a critical mesoscale combine climatic and soil factors and could enable regionally tailored approaches. Here, the Holdridge Life Zone (HLZ) classification proved to be more than a descriptive tool to guide our understanding of soil carbon-climate interaction allowing for linking top-down (from global to local) and bottom-up (from local to global) approaches. In the talk we will present the results for the indiviaul 38 HLZ and present possibilities to add soil internal controls. Regionally tailored solutions can lead to better management of soil carbon. Improving ‘translations’ from the scales relevant for process understanding to the scales of decision-making is key to sustainable soil management and to improve predictions of the fate of our largest terrestrial carbon reservoir during climate change.