Vulnerability indicators : Indicators for soil carbon vulnerability

Soil carbon constitutes the largest terrestrial reservoir of organic carbon, far exceeding the atmospheric storage. In the context of both changing land use and climate, understanding the stability and vulnerability of this soil carbon pool is key. The interaction between geology, climate and soil carbon stability in ecosystems is poorly understood. Presently, there are no tools or measurable soil indicators that can show soil carbon vulnerability.

The project aimed to achieve a better understanding of soil carbon stability and vulnerability in relation to climate change as well as provide tools that can be used as indicators or sentinels of soil carbon vulnerability.

The project provides scientific insights into the relation between carbon turnover and climatic and geologic conditions. It shows that climate only weakly controls soil carbon turnover. Temporal data analysis of soils along a climatic gradient showed that carbon signatures can be overprinted relatively rapidly (decadal timescale) in some ecosystems, whilst others are hardly affected. The vulnerability indicators developed in the project are promising and will be finalised soon.

This project has generated more comprehensive knowledge about the interaction of climate and geology on soil carbon stability and vulnerability.

For greenhouse gas inventories in Switzerland and beyond, the results provide valuable information that will help to improve estimates of the carbon storage and release potential in soils in the context of climate change.

Molecular and radiocarbon sentinels of soil organic matter vulnerability