Aeolian sediment transport and desertification in marginal desert areas in response to climate change

Background

Aeolian dune systems are highly sensitive to climate change. Desertification and dune encroachment pose a significant threat to socio-economic activities. However, research remains limited on how aeolian dune systems respond to past and future climate change [1]. Drylands currently cover 46% of global land area and are home to 38% of the world’s population [2, 3]. Desertification due to climate change – in particular, projected increases in temperature, high-magnitude wind events and the severity of drought events in dryland environments – will affect the abundance and diversity of plant species, reduce crop and livestock productivity, increase wildfire occurrence, and contribute to poverty, food insecurity, and increased disease burden [4]. Populations living in dryland settings, in particular those on the margins of deserts, are predominantly dependent on agriculture, and hence are highly vulnerable to the impacts of desertification driven by climate change [5, 6]. Concurrently, anthropogenic disturbances (e.g., grazing, fire) may further accelerate desert-dune activation, leading to rapid dune construction and migration, and widespread loss of biodiversity. It remains unclear how future climate change will impact aeolian sand mobility, dune construction, expansion and migration, and eco-geomorphic dynamics from regional (tens to hundreds km) to local (m to km) scales. These changes may significantly influence the carbon balance in dryland environments. This project will develop a suite of predictive sediment transport models to assist the global community in adequately preparing for mitigating the effects of ongoing climate change in the coming decades, from geologic, geomorphic, environmental, social and economic perspectives.

 

Aims

This project will combine field survey, remote sensing, and numerical modelling techniques to monitor, assess and predict the impacts of changes in environmental factors (e.g., precipitation, temperature and wind regime) on a wide range of dune landscape evolution and ecological responses of most vulnerable desert-margin areas at different temporal and spatial scales. Furthermore, the project will evaluate the impacts of human activities, such as grazing and fire, on the dune landscape evolution and transformation under potential climate-change scenarios. Communities living at desert margins, who are most vulnerable to climate change and desertification, will be able to use project outcomes and developed tools to guide their land management strategies.

 

Methodology

The successful applicant will collect environmental, sedimentological, topographical, ecological and anthropogenic data using field survey and remote sensing techniques to monitor and assess the evolution of selected dune fields around the world that are typically found at desert margins. They will develop sophisticated algorithms based on a numerical model [7,8] to predict geomorphological dynamics and landscape and ecological evolutions of dune areas that are thought to be most vulnerable to future climate change scenarios. They will also evaluate how human activities, e.g., grazing and fire, might play a role in the intensification of dune activation, and the potential threshold to cause irreversible environmental and socio-economic damage. The developed model will be used as a tool to (i) identify regions worldwide where dune activation is most likely to intensify under further climate change scenarios, (ii) evaluate the potential social-economic consequences, and (iii) guide local authorities in land management strategies.

 

Supervision

The supervisory team possesses extensive expertise in the research of aeolian dune geomorphology and sedimentology, as well as in the development of forward models utilising a range of cutting-edge numerical techniques.

 

Potential of Publication

A major outcome of this project will be the development of predictive models, which will improve our understanding of how aeolian dune systems respond to ongoing climate changes. The appointed candidate will have the opportunity to publish the results of their research in a leading pure or applied research journal, such as Nature Geoscience, Geomorphology, Sedimentology, Aeolian Research, Earth Surface Processes and Landforms, and Global and Planetary Change. The project supervisors have a track record of internationally recognised research publications in this field.

 

Eligibility

Applicants should have a BSc degree (or equivalent) in geography, geology, geology-geography, earth sciences, geophysics or a similar discipline. Skills in numerical modelling are desirable. Experience of using GIS and remote sensing software would be useful, though it is not essential. A background in maths will be useful. Experience of one or more computer programming languages (e.g., Matlab, Python, R, SQL, C#) will also be useful.

 

Training

Training in date collection methods and GIS, and remote sensing techniques will be provided. Training will also be provided in advanced numerical modelling concepts and techniques.

 

 

References:

[1] Baas, A. and L. Delobel., Research Square, 2022. [2] Koutroulis, A.G., Sci. Total Environ., 2019. [3] van der Esch, S., et al., PBL Netherlands Environmental Assessment Agency, 2017. [4] Mirzabaev, A., et al., Special Report on Climate Change and Land of IPCC, 2019. [5] Rosenzweig, C., et al., Proceedings of the national academy of sciences, 2014. [6] Schlenker, W. and D.B. Lobell, Environ. Res. Lett., 2010. [7] Yan, N. and A.C.W. Baas, Geomorphology, 2017. [8] Yan, N. and A.C.W. Baas, Earth Surf. Process. Landf., 2018.