Global soil organic carbon–climate interactions: Why scales matter

Abstract

Soil organic carbon (SOC) holds the largest terrestrial carbon stock because of soil conditions and processes that favor soil carbon persistence. Vulnerable to climate change, SOC may cross a tipping point toward liberating carbon-based greenhouse gases, implying massive self-amplifying SOC-climate interactions.Estimates of SOC persistence are challenging as we still lack broad mechanistic insights. Upscaling mechanistic details from small to larger scales is challenging because the driving factors are not available at the needed resolution. Downscaling is problematic as many modeling studies point to the highest uncertainties deriving from the SOC response to climate change, while models themselves have difficulties in replicating contemporary soil properties and dynamics. To bridge the problems of scaling, strict process orientation seems adequate.Holdridge Life Zones (HLZ) classification, as one example, is a climate classification framework at a mesoscale that provides a descriptive approach to facilitate the identification of potential hotspots and coldspots of SOC-climate interaction.Establishing coordinated experiments across all HLZ, but also including multiple global change drivers, has the potential to advance our understanding of general principles regulating SOC-climate interaction and SOC persistence. Therefore, regionally tailored solutions for both experiments and modeling are urgently needed and can lead to better management of soil and the ecosystem services provided. Improving "translations" from the scales relevant for process understanding to the scales of decision-making is key to good management and to predict the fate of our largest terrestrial carbon stock.

Inorganic carbon is overlooked in global soil carbon research: A bibliometric analysis

“…This underscores the importance of further expansion in the international cooperation and collaboration on soil C research in addressing the challenges of climate change. The exploration of C sequestration in soils as a potential solution to mitigate greenhouse gas emissions is widely recognized and several global initiatives have been launched to support the increase of soil C stocks, with a predominant focus on SOC ( Rumpel et al, 2018 , Jungkunst et al, 2022 ).…”

Controls on timescales of soil organic carbon persistence across sub‐Saharan Africa

“…For example, mean SOC ages from arid and humid climate zones are driven by bio‐climate factors, including GPP and SOC content, whereas reactive minerals are most important in explaining variation in mean SOC ages in seasonal climate zones (Figures 3 and 4). The composition and complexity of the factors operating in the different pedo‐climatic regions highlights the need to incorporate a process‐oriented representation of soils in models that aim to represent C cycling at broader scales, rather than trying to identify a single soil or climate property that best describes SOC persistence (Jungkunst et al., 2022). Our improved understanding also contributes to more process‐oriented future projections of soils under climate change.…”

Soil carbon, nutrient, and vegetation dynamics of an old Anogeissus grove in Mole National Park, Ghana

“…Climate change is a global concern resulting from among others, rising atmospheric carbon dioxide concentrations with devasting consequences including, global warming and erratic weather patterns. The importance of changes in soil organic carbon stocks for global warming scenarios has been recognized early on (e.g., Jones et al., 2005; Jungkunst et al., 2022) with their vulnerability due to soil temperature rise apparent. Thus, mitigation strategies including, soil organic carbon sequestration are gaining increasing attention (e.g., the recent “4p1000” and “recarbonizing global soils” initiatives) through environmentally sustainable land management practices (FAO/ITPS, 2021; Rumpel et al., 2020).…”