Global change impact on vulnerable carbon reservoirs: carbon sequestration and emissions in soils and waters From the Arctic To the Equator – VULCAR-FATE

Previously pristine, the Western Central Africa and Western Siberian Lowlands are now increasingly impacted by accelerated global changes with the predictable degradation of soil and groundwater systems, which could lead to potentially huge emissions of greenhouse gases (GHG) and to vast carbon (C) and nutrient exports from land to oceans. Both regions are characterized by mosaics of open (savanna/tundra) and forest vegetation, that show climate-induced, fire-mediated dynamics suggesting tipping points between contrasted vegetation types. Moreover, two soil classes, podzols and anthrosols, prone to C sequestration but fragile, are common to both regions but little-recognized: their impact on C storage, export and emissions need to be better studied. VULCAR-FATE embraces 1) an approach using multi-satellite data calibrated and validated by ground measurements, and contrasted with information from local knowledge, to monitor the water balance, land use/cover changes and C sequestration by vegetation biomass, and to constrain numerical models of geological processes and water flow, and 2) a hydrological continuum approach taking advantage of existing research stations to quantify and model the export of dissolved and/or particulate organic and inorganic C and other nutrients, and subsequently C sequestration and GHG emissions. The stake of the combined local and regional approaches is to predict the ecosystem's state for the next 30-100 years and to develop in cooperation with local stakeholders a set of recommendations on mitigation of the negative climate-induced and globalization effects. Our interdisciplinary public-private partnership (research organisations, businesses, governmental agencies, NGOs and communities) will join forces and intelligence to design scenarios, decision support data/tools and sustainable management options, and will implement capacity building activities for young scientists, land managers and decision makers. Our transdisciplinary work will thus inform management decisions and policies, and benefit other ANR and EU-ERC projects.