Postgraduate Researcher (Ph.D.)
B.Sc. Geography (1st Class Hons), Queen's University Belfast (2007)
M.Sc. Climate Change, University of East Anglia (2008)
AAAAAAAAAAAAAAAAAAAAAAA Room 02 041 Elmwood BuildingSchool of Geography, Archaeology and PalaeoecologyQueen's University BelfastCounty AntrimNorthern Ireland BT7 1NN E-mail: dmullan15@qub.ac.uk aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaResearch project (Environmental Change cluster)
(Supervisors: Dr Dave-Favis-Mortlock, University of Oxford; Dr Rowan Fealy, National University of Ireland Maynooth; Professor Paula Reimer, Queen's University Belfast; Dr Maarten Blaauw, Queen's University Belfast)
Soil erosion by water is not currently a major issue in Ireland, owing to the predominance of permanent grassland and hence year-round protection of the soil from rainfall and runoff. When the land cover is removed following tillage, however, the soil becomes exposed to the forces of rainfall and flowing water, and ‘a window of opportunity’ is presented for soil erosion to occur. Past evidence suggests tillage was once more important than pasture in Irish agriculture, with a shift from livestock husbandry towards intensive arable farming prompting soil erosion, as evidenced by landscape features such as colluvial steps, documentary sources on traditional farming practices, and sedimentary deposits in lake bottoms. Insufficient protection of the soil following tillage is therefore a key ingredient in the development of soil erosion on agricultural land, as is a sufficient supply of rainfall to exploit the exposed soil. Any changes to the frequency of tillage or the amount/intensity of rainfall may therefore be expected to increase future soil erosion rates.
The potential exists for such changes to increase Irish soil erosion rates under future climate change. Increased rainfall intensity and greater winter rainfall amounts are projected for Ireland, which may result in increased runoff from agricultural land. In addition, projected increases in annual temperatures may cause a shift in land use to accommodate a possible introduction of crops suited to the warmer conditions. Therefore any changes from the current predominance of permanent grassland to arable farming will increase tillage and therefore reduce protection of the soil from erosion.
This project examines the impacts of future climate change on soil erosion by modelling future erosion rates using the Water Erosion Prediction Project (WEPP) model (Flanagan and Nearing, 1995) for a selection of sites in the north of Ireland, chosen to maximise variability in geography, land use, soil type etc. Most previous studies of soil erosion under future climate change (eg. Favis-Mortlock and Boardman, 1995; Pruski and Nearing, 2002; Kim et al, 2009) use raw General Circulation Model (GCM) output to perturb the erosion model to represent changed climate conditions. Due to the coarse spatial resolution of GCMs and the much finer scale nature of soil erosion, however, some method of generating higher resolution climate change projections is desirable to more robustly model future erosion rates for individual sites. In this study, the Statistical DownScaling Model (SDSM) (Wilby and Dawson, 2007) is used to ‘downscale’ coarse GCM output to the point-scale. This makes possible the assessment of site-specific future rainfall and temperature changes upon future soil erosion rates. In addition, despite the crucial importance of land use, and hence vegetation cover, most previous climate change- soil erosion studies assume that land use will continue unchanged into the future (Favis-Mortlock and Guerra, 1999). Here, potential future land use scenarios for the modelled sites are considered, to examine how both direct and indirect impacts of climate change may impact future soil erosion rates in Ireland.
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Research interests
I am interested in many aspects across the earth, environmental and atmospheric sciences, including synoptic climatology, climate modelling, downscalinng climate change projections, geomorphology, environmental modelling, soil erosion by water, and geography education.
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Publications
(1) Favis-Mortlock, D.T. and Mullan, D.J. (2011) Soil erosion by water under future climate change, In: Shukla, M. (ed.) Soil hydrology, land use and agriculture. Oxford: CABI, pp. 384-414.
(2) McCabe, S., Smith, B., Adamson, C., Mullan, D. and McAllister, D. (2011) The "greening" of natural stone buildings: quartz sandstone performance as a secondary indicator of climate change in the British Isles? Atmospheric and Climate Sciences. doi: 10.4236/acs.2011.14018
(3) Mullan, D.J. and Favis-Mortlock, D.T. (2011) Managing soil erosion: a case study from Ireland. Geography Review 24(4): 24-26.
(4) Mullan, D.J., Favis-Mortlock, D.T. and Fealy, R. (In Review) Modelling the impacts of climate change on future rates of soil erosion: addressing key limitations. Agricultural and Forest Meteorology.
(5) Mullan, D.J., Fealy, R. and Favis-Mortlock, D.T. (2011) Developing site-specific future temperature scenarios for Northern Ireland: a statistical downscaling approach. International Journal of Climatology. doi: 10.1002/joc.2414
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Teaching and demonstrating
Level 1 Physical Geography (1st semester, 2008/09) - classroom group teaching and practical marking
Level 1 Introduction to Earth Science (2nd semester, 2008/09; 2009/10) - field group teaching
Level 2 Acquisition and analysis of geographical information (1st semester, 2008/09; 2009/10; 2010/11) - practical class assistance and practical marking
Level 2 Field and research techniques in geographical practice (2nd semester, 2009/10; 2010/11) - field and classroom teaching
Level 2 Water, atmosphere and society (2nd semester, 2009/10) - report marking
Level 2 Sustaining the Biosphere (2nd semester, 2010/11) - development and delivery of 3 lectures
Level 2 Climate Change: Science, Impacts and Policy (1st semester, 2011/12) - practical class assistance
Level 3 Coastal Environments (2nd semester, 2008/09) - field group teaching
Level 3 Catchments: geomorphology, hydrology and environmental management (2nd semester, 2008/09) - development and implentation of a new practical
Level 3 Sea Level Change: past, present and future (1st semester, 2011/12) - field and laboratory assistance
Society membership
Irish Meteorological Society
Royal Meteorological Society
British Society for Geomorphology
Soil Science Society of Ireland
Geographical Society of Ireland
Presentations, conferences and workshops
(7) International Symposium on Erosion and Landscape Evolution, Anchorage, Alaska, USA (September 2011)
Mullan, D.J., Favis-Mortlock, D.T. and Fealy, R. (2011)Modelling the impacts of climate change on future rates of soil erosion: Addressing key limitations. International Symposium on Erosion and Landscape Evolution Conference Proceedings, 18-21 September 2011, Anchorage, Alaska.
(6) European Geosciences Union, Vienna, Austria (May 2010)
Mullan, D.J. and Favis-Mortlock, D.T. (2010) Modelling the impact of climate change on future rates of soil erosion: a case study from the north of Ireland. EGU General Assembly.
(5) Conference of Irish Geographers, National University of Ireland, Maynooth (April 2010)
Mullan, D.J., Fealy, R. and Favis-Mortlock, D.T. (2010) Downscaling global climate models to produce site-specific future temperature scenarios for the north of Ireland. CIG, Maynooth.
(4) Weather and Climate Conference, Irish Meteorological Society, Glasnevin, Dublin (March 2010)
Mullan, D.J., Fealy, R. and Favis-Mortlock, D.T. (2010) Developing site-specific future temperature scenarios for the north of Ireland. IMS, Dublin.
(3) School of GAP research day, Queen's University Belfast (January 2010)
Mullan, D.J. (2010) Developing site-specific future temperature scenarios for the north of Ireland.
(2) Differentiation presentation, Queen's University Belfast (June 2009)
Mullan, D.J. (2009) Future climate change: the potential for increased soil erosion by water in Northern Ireland.
(1) Windsor Workshop, London (December 2008)
Mullan, D.J. (2008) Future climate change: the potential for increased soil erosion by water in Northern Ireland.
Media involvement
(3) UTV Studio interview entitled 'Stormy outlook' (June 2011)
http://www.u.tv/utvplayer/video/137208/112404/7a259635-8bc7-4eae-8984-3f8afdb66cd4
(2) BBC Radio Ulster interview on 'Changing weather patterns' (April 2011)
(1) Downtown Radio interview on 'Severe winter weather' (December 2010)
Academic awards
Winner of Estyn Evans prize for top Geography dissertation (2007)
Runner-up of Sarah M. Holland memorial prize for overall performance in Geography degree (2007)