VULCAR-FATE

The VUCAR-FATE project

The VULCARE-FATE (Global change impact on VULnerable CARbon reservoirs: carbon sequestration and emissions in soils and waters From the Arctic To the Equator) was selected as part of the Belmont Forum’s call “Towards Sustainability of Soils and Groundwater for Society (Soils 2020)”. The kick-off meeting was held in June 2021 during the conference « Sustainability Research & Innovation Congress 2021 » in Brisbane, Australia…

The VULCAR-FATE consortium, led by IRD, includes IFP Energies nouvelles (IFPEN, France), Florida State University (FSU, United States of America) and Tomsk State University (Russian Federation) as than funded institutions. As self-funded partners, the consortium also involves the Autonomous University of Barcelona (UAB, Spain), the National Center for Scientific Research (CNRS, France) and the non-governmental organization The Nature Conservancy (TNC-Gabon, United States). United States of America), the world’s largest conservation NGO. The project also associates many academic partners and stakeholders in Gabon and the Russian Federation.

The Earth’s Critical Zone, which sustains nearly all terrestrial life, is the “heterogeneous, near surface environment in which complex interactions involving rock, soil, water, air, and living organisms regulate the natural habitat and determine the availability of life-sustaining resources”. In the world-wide effort to improve the knowledge of the Critical Zone’s long-term response to environmental, societal and economic drivers, the tropical socio-ecosystems of Western Central Africa (WCA), and those of Arctic and sub-Arctic zones of the Western Siberian Lowlands (WSL) are all under-studied although both regions have been recognized as crucial for the future of the biosphere and of humanity.

Well known for their carbon storage, these regions of low population density are now undergoing accelerated changes due to growing human activities with the predictable degradation of soil cover, groundwater, and river and lake systems. These changes are combined with the effects of climate change, that could lead to potentially huge emissions of greenhouse gases (GHG) and sizable increase in carbon, including black carbon, and nutrient export from land to oceans. The sensitivity to climate of carbon in humid tropical ecosystems – both aboveground biomass and belowground carbon stocks – and in peat and wetlands of the WCA is thus a key uncertainty in predicting global climate change. Today, rivers and lakes of the WSL are amongst the world’s largest pools of carbon storage but also the most powerful emitters of CO₂ and CH₄ due to thawing permafrost.

In both regions, highly contrasted vegetation classes are observable (forest vs. savannah and taiga vs. tundra) that strongly differ in albedo and in levels and modalities of carbon storage. Understanding of global change-driven dynamics of vegetation cover is thus quintessential for the future of carbon balance and stocks. Fires are pervasive, although crown fires in taiga are intrinsically different from savannah surface fires. But in both cases, interactions and feedbacks between vegetation states and fire regime diversify pathways that vegetation is liable to follow under climate change. Moreover, human practices also influence the fire regime. If forest encroachment over savannahs is a widespread pattern in West and Central Africa over the last 70 years, it suffers exceptions that call for investigation. Similarly, the northward (upward) tree-line movement is not ubiquitous. Notably, manmade tundra and ‘paludification’ contribute to uncertainty in the future changes of the tundra-taiga boundary

In both regions, there exist also other environments that are rarely taken into account by scientists and policy-makers, although they constitute cultural and natural heritages that supply important ecosystem services, including long-term carbon storage in soils. Both regions harbour podzols, soils that store large quantities of carbon, sequestered in forms that are reputed to be resistant to alteration, and anthrosols, which, as a cultural heritage, testify to the long history of societies’ interactions with their environments, helping create a sense of place and identity. Podzols and many anthrosols share an important trait: storage of large stocks of carbon that may be vulnerable to anthropogenic environmental change.