Concept and objectives
CARBO-Extreme aims to
- improve our understanding of the terrestrial carbon cycle in response to climate variability and extreme events
- represent and apply this knowledge over Europe with predictive terrestrial carbon cycle modelling
- interpret the model predictions in terms of vulnerability of the terrestrial – in particular soil – carbon pools under different scenarios and give advice to the European Commission and other stakeholders to support the development and implementation of climate, soil and ecosystem protection policies.
This overall objective is broken down into the following scientific, technical and policy related objectives:
Main scientific objectives
- Obtain a better and more comprehensive predictive understanding of terrestrial carbon cycle responses to climate variability and extreme weather events for European forest, grass- and peat-land and arable ecosystems.
- Identify the most sensitive and vulnerable carbon pools and processes to climate variability and extreme events
- Map the most likely trajectory of carbon pools in Europe over the 21st century and associated uncertainties introduced by model assumptions and setup (i.e. model structure, parameters and input, e.g. scenarios)
Specifically the following scientific questions will be addressed in the project:
- How do ecosystem carbon balances respond to changing climate variability in contrast to gradual climate change?
- How sensitive is the carbon balance of different European ecosystem types to climate extremes? Are there vegetation- and soil-specific thresholds?
- Which are the processes that dominate the ecosystem's carbon balance sensitivity and vulnerability under climate variability and extreme events?
- Is temperature the main determinant of changes in carbon balance and potential saturation of the carbon sink or is it overridden by water limitation or by interactions between temperature and water?
- Will destabilizing mechanisms of soil carbon be more affected than stabilizing mechanisms by climate extremes? Will this enhance the vulnerability of soil C to climate change?
- Which lagged responses and memory effects play an important role for long term terrestrial carbon balance? Which part of the growing season is most sensitive to climate extremes, with implications for cultivation practices?
Main technical objectives
- Build a European network of Ecosystem Manipulation Experiments by harmonizing existing experiments and amending with cross-site process studies in-situ and in the laboratory.
- Build a consistent multi-source (ecosystem experiments, long-term monitoring of soils, trees and fluxes, remote sensing, riverine transport) database on the European carbon cycle components for use in studying climate variability and extreme events
- Perform a Bayesian model calibration and comparison that allows multiple observational constraints to be assimilated into process models across different time and spatial scales, leading to improved terrestrial carbon cycle predictions and a refined assessment of their uncertainties in scenario analyses
- Select and integrate the available and most suitable spatial data for predictive carbon cycle modelling (e.g. soil maps, land-use, regional climate scenarios)
Main policy relevant objectives
- Provide an integrated analysis of critical vulnerabilities of the terrestrial carbon sink and carbon pools in Europe, in a spatially explicit way and aggregated by country and sectors/ecosystem types.
- Quantify the risk of not attaining targets in European emission reductions due to increased greenhouse gas losses from European terrestrial ecosystems
- Compare carbon pools trajectories in Europe for contrasted CO2 emission scenarios and assess the additional mitigation efforts that might be needed to compensate for the decline in the European terrestrial carbon sinks.
- Give guidance on ecosystem-type and region-specific carbon and soil protection strategies for post-Kyoto policies, i.e. negotiations for a long-term agreement on emissions cuts (‘Bali roadmap’).
- Strengthening the competitiveness of the European carbon cycle research by bringing together different experimental, observational and modelling communities for an integrated assessment.