Impacts of Climate Change on Erosion, Sediment Transport and Soil Carbon in the UK and Europe

Lead Research Organisation: NERC CEH (Up to 30.11.2019)
Department Name: Boorman

Abstract

For the government agencies and statutory bodies responsible for management of land and water resources, the past decade has witnessed growing recognition of a series of pressing environmental issues and an awareness that significant uncertainties exist concerning their future trajectories: 1. Erosion by water is the most severe threat to soil in Europe (Kirkby et al., 2004). Furthermore, rates of soil erosion are sensitive to changes in surface runoff, yet spatially-explicit predictions of future erosion rates under changing climatic conditions are not yet available. 2. Redistribution of soil by agricultural tillage is a key influence on the evolving spatial variability of soil properties and productivity (Quine and Zhang, 2002), and consequently exerts a strong control on the emission and sequestration of soil carbon from arable land (Van Oost et al., 2004, 2005). Soils are expected to represent an important control on carbon cycle feedbacks under changing climatic conditions (Cox et al., 2000). However, the role of soil erosion and redistribution in the carbon cycle remains an area of significant controversy, with estimates of the global carbon flux associated with erosion ranging from a 1 Gt/year source to a 1 Gt/year sink (Stallard, 1998; Lal, 2003). 3. Delivery of eroded sediment to river channels causes many environmental problems including diffuse pollution, transport and storage of fine sediment and associated contaminants, degradation of aquatic ecosystems, and changes in flow conveyance capacity and flood frequency due to in-channel and overbank sedimentation (Walling et al., 1999, 2001; Greig et al., 2005). Defra and the Environment Agency currently face the significant challenges posed by implementation of the EC Water Framework Directive (WFD) and the requirement to address the issues highlighted above in order to manage and maintain the ecological status of all surface waters. Furthermore, potential changes in the threats posed by these problems under future climates have yet to be quantified. Tackling these challenges at national and regional scales will necessitate the development of new modelling approaches capable of investigating the feedbacks between climatic, hydrologic, geomorphic and biogeochemical processes, which are poorly understood at present. This project will link CEH and Met. Office expertise in regional climate and hydrological modelling with geomorphological models developed by the universities of Leeds and Exeter to build for CEH a solid, strategic platform from which to address this set of fundamental scientific and environmental questions, which lie at the heart of the EHFI programme, and are central to both CEH and NERC's core missions. This project will build on recent modelling advances to develop new models in the following areas: 1. Hillslope hydrology and soil erosion; 2. Sediment routing within rivers, flood conveyance and floodplain sedimentation; 3. Soil redistribution on hillslopes and soil organic carbon dynamics on slopes and floodplains. All model components will be evaluated and assessed using a wide range of existing data sources. Models will then be implemented within an integrated framework to examine environmental responses to climate change over the next century in the UK and at selected sites in Europe. Key questions that will be addressed using this approach include: 1. What are the effects of projected future changes in climate on soil erosion and sediment delivery into and through river channels? 2. What are the projected effects of climate change and accelerated erosion on river channel morphology, and how might these changes alter future flood risk and sediment storage on floodplains? 3. Can the effects of future changes in climate on the redistribution of soil organic carbon within the landscape be quantified and incorporated as a feedback into future models of terrestrial carbon biogeochemistry? Note: References are in case for support

Publications

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Dadson S (2013) Water security, global change and land-atmosphere feedbacks. in Philosophical transactions. Series A, Mathematical, physical, and engineering sciences

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Dadson S (2010) Geomorphology and Earth system science in Progress in Physical Geography: Earth and Environment

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O. Slaymaker, T. Spencer And S. Dadson (2009) Geomorphology and Global Environmental Change

 
Description Erosion by water is among the most severe threats to soil in Europe. Moreover, delivery of eroded sediment to river channels causes many environmental problems including diffuse pollution, transport and storage of fine sediment and associated contaminants, degradation of aquatic ecosystems, and changes in flow conveyance capacity and flood frequency due to in-channel and overbank sedimentation. Whilst rates of soil erosion are sensitive to changes in surface runoff, spatially-explicit predictions of future erosion rates under changing climatic conditions are not widely available. In this project we developed a modelling framework suitable for addressing interactions between climatic, hydrologic, geomorphic and biogeochemical processes at national and regional scales, and provided a preliminary evaluation of the potential impact of future climate change on soil erosion, and sediment delivery and transport in river channels and floodplains. We used the model to provide regional projections of sediment delivery and transport and identified areas where erosion is locally important.
Exploitation Route Yes, research continues in sediment erosion and delivery at the national and continental scale.
Sectors Environment

 
Description Elucidating the variable residence times of catchment-derived soil organic carbon in floodplain soils. 
Form Of Engagement Activity Scientific meeting (conference/symposium etc.)
Part Of Official Scheme? No
Geographic Reach International
Primary Audience
Results and Impact American Geophysical Union General Assembly, San Francisco
Year(s) Of Engagement Activity 2013
 
Description Geomorphologically-determined variation in SOC residence time on floodplains: reconstruction and simulation. 
Form Of Engagement Activity Scientific meeting (conference/symposium etc.)
Part Of Official Scheme? No
Primary Audience Participants in your research or patient groups
Results and Impact Presentation at 3rd International Symposium on Soil Organic Matter
Year(s) Of Engagement Activity 2011
 
Description Systematic variation in catchment-derived SOC preservation with geomorphic context in floodplain soils: insights from SOM Fractionation and stable isotope analysis 
Form Of Engagement Activity Scientific meeting (conference/symposium etc.)
Part Of Official Scheme? No
Primary Audience
Results and Impact Presentation at 4th International Symposium on Soil Organic Matter 2013, Nanjing.
Year(s) Of Engagement Activity 2013