More about the Programme
Carbon stored in soils represents the largest terrestrial carbon pool. Consequently, we cannot begin to understand the controls on the terrestrial carbon balance until we have a thorough understanding of the “ins and outs” of soil carbon. In practice, however, most carbon balance research has focussed effort on the aboveground parts of ecosystems. It’s not hard to see why. Whereas the carbon stocks and fluxes of the aboveground parts can be quantified with relative ease, those of the belowground parts cannot.
That is not to say, however, that little is known about the processes taking place within the soil. On the contrary, there exists a huge amount of knowledge relevant to the carbon cycle in soils. The main problem is that most of this knowledge resides with those engaged in “traditional” soil science, rather than with those engaged in carbon balance studies. This ESF programme has been set up to help break down the distinction between these two communities of scientists, and to develop closer integration with a third group of scientists, the modellers.
The programme seeks:
- To increase confidence in soil carbon flux and stock change estimates to generate datasets that are reliable and consistent.
- To develop a new generation of models describing soil carbon dynamics.
- To investigate the effects of perturbation on soil carbon balance and the potential for mitigation of carbon missions.
Background to the Programme
The largest terrestrial carbon pool
Carbon stored in soils represents the largest terrestrial carbon pool. Knowledge of the dynamics of this pool is essential if we are to understand the terrestrial carbon balance as a whole. Because inter-annual changes in soil carbon stocks are small compared to the total carbon stored in soils, determining the dynamics of the soil carbon pool by repeated “stocktaking” is difficult. Inaccuracies also confound attempts to measure, directly, the flux of CO2 from the soil. Furthermore, we must also deal with considerable spatial and temporal variability – how do we “scale” measurements made at a limited number of locations, over a limited period, to provide a meaningful description of the long-term dynamics of soil carbon at the regional, continental and global scales?
Soils and climate change
Soils and climate change interface in two major ways. Firstly, because the rate of carbon loss from soil is, to some extent, a function of temperature, soil carbon balance is likely to be a sensitive indicator of climate change. If soil carbon stocks become depleted, long-term sustainability of agricultural production on these soils becomes questionable. Secondly, there has been considerable speculation, particularly in the US, about the potential for changing land management practices to increase the amount of carbon stored in soils as a means of offsetting CO2 emissions from other sectors. The environmental and economic benefits of this form of carbon sequestration are huge, but as of now, we simply do not have the scientific basis with which to judge the theoretical and practical validity of these ideas.
Needs in soil carbon research
Thus there is a great and urgent need to develop methods of studying and describing soil carbon balance that are scientifically valid, and recognised as being so. At this time, however, we do not have a complete understanding of the various soil processes that affect carbon. Equally importantly, none of the models that we currently use summarise all the understanding we do have.
Achieving an international consensus on how to include soils in carbon accounting procedures demands that methods of determining, reporting and verifying changes in soil carbon stocks are scientifically valid. To contribute to this, soil carbon research must become more coherent, and must develop greater linkages between pure- and applied scientists, between modellers and experimentalists and between scientists, economists and policy-makers.
The ESF Programme
A multidisciplinary programme
In general, the question of understanding soil carbon balance is of major concern to two, quite distinct, scientific communities: soil scientists and carbon budget researchers. Soil scientists have traditionally been concerned with describing general trends in soil carbon stocks, whilst the carbon budget communities are interested in soil carbon dynamics because they want to understand carbon fluxes of ecosystems. It is recognised by the ESF that scientific progress is made when bridges are built between disparate scientific disciplines, and it is the overarching aim of this programme to foster synergistic interaction between these two groups. We further hope to develop collaborations with yet more scientific communities, for example microbiologists, plant physiologists, chemists and atmospheric physicists.
Modelling is an example of a topic where the interdisciplinary approach taken by the proposed programme could lead to considerable progress. Models produced by soil scientists tend to have long time-steps, and tend to focus on partitioning the soil carbon pool into different sub-pools. These models are generally very good at reproducing, for example, geo-climatic influences on soil carbon distribution, but are less good at describing fine resolution details such as the carbon fluxes at individual sites. On the other hand, the models used by the flux measuring community tend to be short time-step models describing instantaneous soil CO2 efflux. These models explain most of the daily and annual variation of the CO2 efflux at particular sites but cannot explain differences between sites and do not attempt to describe long-term carbon dynamics. We hope to bring together these different modelling communities, to bridge the gap in our modelling efforts, and to facilitate the development of a new generation of soil carbon balance models – ones that can describe fluxes well at the individual site level as well as longer-term trends in soil organic carbon across many sites.
The programme will bring together scientists to find ways of reducing uncertainties associated with stock change and flux estimates at site, national and continental levels. This will be done by devising means of cross-validating carbon stock changes inferred from flux measurements and directly measured stock changes.
A European level programme
Soils in Europe span the range from the massive carbon stores in the boreal region to the semi-arid, desertification-prone soils of the Mediterranean, and from the rich, intensively farmed soils of the low counties to the thin, erosion-prone Alpine soils. At the national level, individual countries tend to fund research focussing on their own, local, conditions and concerns. There is a powerful case for having a consolidated research effort into the terrestrial carbon balance at the continental scale. The beginning of the first Kyoto commitment period in 2008 underlines the urgent need for action. This programme aims to bring together soil carbon researchers from all these regions to create a whole-Europe perspective on the role of soils in the terrestrial carbon balance.
Scope and Scientific Objectives
Increasing confidence in carbon flux and carbon stock estimates
The first step towards understanding the soil carbon balance is to be able to make accurate measurements of soil carbon dynamics, notably CO2 fluxes and carbon stock changes. The difficulties of measuring soil CO2 fluxes are well documented, but measuring the carbon stock of soils is no less difficult. Two major uncertainties remain. First is the difficulty in getting a spatially representative measurement. Geostatistics can help us predict how many samples are needed to bring our estimates to within an acceptable error range. But will it ever be economically feasible to measure small enough changes in carbon stocks against the large carbon stocks present in most soils? Second, should we concern ourselves with total organic carbon or should we equate “sequestered” carbon with carbon that is completely inert (recalcitrant)? Clarifying these issues will be the focus of workshops within the programme.
Dealing with heterogeneity and scale provides methodological challenges in the design of experiments to investigate soil carbon balance. Two are particularly important at the European level. Firstly, there is a need to describe the soil carbon balance of ALL Europe. The proposed programme will include people from every part of Europe and will stimulate the European perspective necessary for successful integration of local measurements to the regional and continental scales. Secondly, we need to devise ways to investigate the long-term behaviour of the soil carbon balance. The difficulties of studying long-term phenomena within a reasonable time-period are obvious, and require that novel experimental methods and modelling techniques be developed. What sorts of methods can we use when our objectives are so large-scale and long-term? What combination of local measurements, remote sensing and modelling yields the most useful/reliable estimates? This programme will provide the opportunity for assessing scientific priorities and formulating the ideas necessary to address them.
A new generation of soil carbon dynamics models
Several disparities suggest that we need a new generation of models to describe soil carbon dynamics. Firstly, the disparity between what we have now and what we need, and secondly, the disparity between what we know and what is currently included in our models. Whilst there is unlikely to be a single ubiquitous model, we hope that by bringing together scientists from different disciplines, (pure scientists with new process understanding, modellers with experience of describing processes mathematically, ecologists with access to various datasets, etc.) we can create a state-of-the-art modelling framework that can be simplified in different ways according to different users requirements.
The effects of perturbation and the potential for mitigation
To compliment and build on the scientific and modelling advances that will come out of the programme, we will consider two questions: What are the effects of environmental perturbation on soil carbon balance and what is the potential for using soils to mitigate CO2 emissions.
Perturbations may be caused by climate change, they may be a normal part of the land-use routine (e.g. disturbances in agriculture or forestry rotations), or they may be the consequence of a policy-driven change in management practice. The effects of these perturbations are huge. For example, an estimated 100 billion tonnes of soil carbon has been lost through human activity, particularly agriculture. In the latter part of the programme, we hope to use the model structure we have built up to explore the possible consequences of present and future perturbations.
Although organic matter in soils is already the largest terrestrial carbon pool, there is speculation that potential exists to increase the amount of carbon stored in soils still further. Over the next 50 to 100 years, it is estimated that between 40 and 80 billion tonnes of carbon could be sequestered in agricultural soils alone. On the other hand, there is a body of opinion that soil carbon stocks are governed by geo-climatic factors, and the potential for mitigating CO2 emissions by carbon sequestration in soils is overestimated. As carbon “credits” become a recognised commodity, there is a need for science to address the assumptions upon which these differing opinions are based. This programme will provide the forum and modelling tools that will allow us to consider the carbon sequestration question in it’s entirety – from the basic science governing the dynamics of soil carbon stocks, to the cost-benefit analyses of, for example, taking land out of agricultural production and managing it for carbon sequestration.
For these tasks, the programme will include scientists from out with the soil community, for example agricultural economists and land use planners. In this way, we will generate two-way dialogues that inform the wider global change debate with soil-related scientific knowledge as well as adding relevance to our own scientific work by placing it in a broader context.
Activities
Programme activities include:
- Science Meetings (Workshops, Summer Schools & Conferences)
- Short Visit and Exchange Grants [CLOSED]
If you wish to receive information on Programme activities please join the Programme email mailing list.
Further information on Programme activities at Go to Website
A brochure containing information on the scientific background and aims and objectives of the programme has been published. If you wish to receive a copy of this brochure send an email with your full postal address to
- EllenDegott-RekowskiE-Mail
- Senior Administrator
The brochure can also be downloaded by clicking here (PDF 288 KB).
Links to other Programmes/Activities
- Forest Soil Co-ordinating Centre Go to Website
- ICP Forests Go to Website
