Surface & Reservoir

REPRISE – Funding: STIC-AmSud / Lead: Bertrand Guenet
Future climate changes are mainly projected by Earth System Models. Climate scientists do not rely on a single model and several models have been developed in the world. Thanks to the ensemble of multiple models we can calculate future climate trajectories and associated uncertainties. One source of uncertainty comes from models’ structure and how the different mechanisms are represented and parameterized. One of the main challenges for climate scientists is to reduce such uncertainties. One possible option is the model development, but this is time consuming and needs large computing and human resources. The second option is to constraint model projections based on present day observations, in order to calculate biases and then correct the modelled data. This approach is known as emergent constraint framework. In the REPRISE collaboration we will analyse current Earth System Model simulations and analyses different output variables related to the carbon cycle, land use and climate, which will be compared to observations-based products. This work will be done through two work packages. The first one will focus on the emergent constraint framework to reduce uncertainties in future projections for specific outputs variables and regions. The second one will look at the model residues and identify their drivers to underlined specific aspect of the Earth system models that must be improved to reduce climate projections uncertainties. These two work packages will be done with a special focus over South America in order to reduce the climate change uncertainties over this region. Two additional work packages dedicated to funding exploration and to results communication/dissemination will also be included to ensure that the current consortium continues after the REPRISE project and to reach local stakeholders.

CHROME – Funding: Marie Skłodowska-Curie / Lead: Nuria Catalan
Organic carbon is exported from terrestrial to freshwater ecosystems where, not only is it being degraded and eventually lost as carbon dioxide, but such degradation occurs faster than in soils or marine systems. Across freshwaters, variations in organic matter degradation and reactivity have been related to compositional changes in organic matter. The flux from terrestrial to aquatic systems seems to be increasing associated to anthropogenic perturbations. However, despite the relevance of these fluxes for the global C cycle, Earth System Models (ESMs) are just starting to consider them. In that sense, a particularly crucial region deserving urgent attention is the Arctic, as permafrost soils hold a massive C stock that is vulnerable to being mobilized towards freshwaters. Such transfer could turn that vulnerable C stock from a sink into a carbon dioxide source. Therefore, determining the reactivity of that organic matter flux and incorporating it in surface models is key at the moment. The foundation of CHROME is the idea that the chemical diversity of organic matter explains its reactivity and, as such, should be considered in biogeochemical models. CHROME represents the first attempt to incorporate organic matter chemical diversity to ESMs, and will do so by: i) developing and selecting functional chemical diversity indices as indicators of Arctic organic matter reactivity and ii) implementing that knowledge in a regional branch of an ESM.

CCiCC – Funding: H2020 / Lead: Pierre Friedlingstein
CCiCC addresses the crucial knowledge gap in the climate sensitivity to carbon dioxide emissions, by reducing uncertainty in our quantitative understanding of carbon-climate interactions and feedbacks. This will be achieved through innovative integration of models and observations, providing new constraints on modelled carbon-climate interactions and climate projections, and supporting IPCC assessments and policy objectives. To meet this objective, CCiCC will (a) provide a step change in our ability to quantify the key processes regulating the coupled carbon-climate system, (b) use observational constraints and improved processes understanding to provide multi-model near-term predictions and long-term projections of the climate in response to anthropogenic emissions, and (c) deliver policy-relevant carbon dioxide emission pathways consistent with the UNFCCC Paris Agreement (PA) goals. To achieve its goals, CCiCC will develop and use: state-of-the-art Earth System Models (ESMs) including biogeochemical processes not included in previous IPCC reports; novel observations to constrain the contemporary carbon cycle and its natural variability; ESM-based decadal predictions including carbon-climate feedbacks and novel initialisation methods; novel emergent constraints and weighting methods to reduce uncertainty in carbon cycle and climate projections; and novel climate scenarios following adaptive CO2 emission pathways. CCiCC will support two central elements of the PA. First, the PA global stocktakes, by providing policy-relevant predictions of atmospheric CO2 and climate in response to the national determined contributions. Second, the PA ambitions to keep global warming well below 2°C, by providing robust estimates of the remaining carbon budgets and available pathways. CCiCC will bring together leading European groups on climate modelling and on carbon cycle research, uniquely securing Europe’s leadership in actionable science needed for the IPCC assessments.

HoliSoils – Funding: H2020 / Lead: Raisa Mäkipää
Knowledge gaps on forest soil processes and lack of a harmonised soil monitoring limit the EU’s ability to maintain soil related ecosystem services and to reach climate policy targets. A better understanding of the soil processes and a harmonised approach to manage and integrate data to computational models that are used for decision making is urgently required in order to meet climat and sustainability goals, including the UN’s Agenda 2030 SDGs, the Paris Agreement of Climate Convention, the EU Bioeconomy Strategy, the EU’s LULUCF Regulation, the EU Forest Strategy (2018), and the European Green Deal. HoliSoils will develop a harmonised soil monitoring framework and identify and test soil management practices aiming to mitigate CC and sustain provision of various ecosystem services essential for human livelihoods and wellbeing. HoliSoils incorporates novel methodologies and expert knowledge on analytical techniques, data sharing, soil properties and biodiversity, and processes with model development, in order to develop tools for soil monitoring, refine GHG assessment of the LULUCF sector, enhance efficiency of GHG mitigation actions, and improve numerical forecasting of soil-based mitigation, adaptation, and ecosystem services. HoliSoils applies a collaborative multiactor approach, in order to maximise its applicability and impact beyond its duration. The multidisciplinary consortium consists of universities and research institutes from across Europe, with leading expertise on soil analysis and databases, development of advanced analytical techniques, complex system modelling, digital soil mapping, soil ecology, disturbance ecology, forest and GHG inventories, social sciences, and communications. It also involves active engagement with diverse stakeholders, including forest owners and managers, industry actors, forest extension services, a certification body, forest and soils researchers, climate policy support and GHG inventory experts, and policymakers.

ROCOCO – Funding: ADEME / Lead: Lauric Cecillon
While the National Forest and Wood Programme aims to increase wood harvesting in France, the 4p1000 France study stresses the importance of monitoring the effects of intensified silvicultural management on soil organic carbon (SOC) stocks, with the objective of preserving or enhancing the net SOC sink constituted by French forest soils. However, monitoring the effects of increased biomass mobilisation in forests on SOC stocks is made very difficult because there is no validated SOC dynamics model under French forest conditions. Our ROCOCO project aims to remove the scientific barrier of a failing model of SOC dynamics in forests. As such, it is part of Axis 2 of the APR GRAINE. It focuses on one of the priorities of the 2019 edition concerning forest management and wood industries: “modelling the effects of forest management on soil carbon”. The objectives of the ROCOCO project are as simple as they are ambitious: to improve SOC dynamics models to make them more predictive of the changes observed in French forests (by making them compatible with a method quantifying SOC stability and by simplifying them); to use the improved models to simulate changes in SOC stocks in all French forests by 2050 under different forest management and climate scenarios. Our ROCOCO project will thus provide the scientific community and forest managers with operational SOC dynamics models and robust projections of SOC stock changes by 2050 under different climate and forest management scenarios. These projections will be able to more objectively inform public policies aimed at increasing wood harvesting in France with regard to their compatibility with the national low-carbon strategy.

Chaire Channel – Financement : Fondation Channel / Pilotage : Laurent Bopp
The ocean moderates and controls the timing of anthropogenic climate change.  It has absorbed the vast majority of excess heat in the climate system—more than 90% since the 1970s. It is also an enormous carbon sink—each year it absorbs several billion tonnes of carbon. It has captured almost 30% of anthropogenic carbon emissions since the start of the industrial period, thereby significantly reducing the increase in the concentration of CO2 in the atmosphere. The oceans moderating impact on anthropogenic climate change comes at a cost: it warms up by absorbing heat and it acidifies by absorbing carbon. These changes in the fundamental physico-chemical properties of the ocean (warming, acidification) have repercussions on the functioning of ecosystems and on marine species by modifying their geographical distribution, their basic physiology, and their seasonal rhythms. Nevertheless, the ocean is also a source of potential solutions to mitigate climate change. Coastal ecosystems, mangroves, salt marshes, seagrass beds and macroalgae constitute what is known as “Blue Carbon”. By protecting and restoring these very productive ecosystems could significantly increase the Earth’s carbon storage capacity and reduce the rate of atmospheric CO2 increase in the atmosphere.
Despite significant advances, our understanding of the role of the ocean in climate change projections for the coming decades is still limited. What will be the evolution of the ocean carbon sink in the 21st century? What will be the impacts of ocean acidification on marine ecosystems? Similarly, the quantification of the potential role of “blue carbon” in mitigating climate change is still very incomplete. This quantification is mainly based on local terrain data that has been extrapolated to the entire globe. How can we improve our estimates of blue carbon?