Looking for evidence of climate change impacts in the eastern Irish Sea 1Cities Institute, London Metropolitan University, Ladbroke House, 62-66 Highbury Grove, London, N5 2AD, UK
14 Jun 2011
2ABPMer, Suite B, Waterside House, Town Quay, Southampton, SO14 2AQ, UK
3National Oceanographic Centre, Joseph Proudman Building, 6, Brownlow Street, Liverpool, L3 5DA, UK
Received: 10 February 2011 – Revised: 13 April 2011 – Accepted: 26 April 2011 – Published: 14 June 2011Abstract. Although storminess is often cited as a driver of long-term coastal erosion,
a lack of suitable datasets has only allowed objective assessment of this
claim in a handful of case studies. This reduces our ability to understand
and predict how the coastline may respond to an increase in "storminess" as
suggested by global and regional climate models. With focus on 16 km
of the Sefton coastline bordering the eastern Irish Sea (UK), this
paper analyses available measured datasets of water level, surge level, wave
height, wind speed and barometric pressure with the objective of finding
trends in metocean climate that are consistent with predictions. The paper
then examines rates of change in shoreline position over the period 1894 to
2005 with the aim of establishing relationships with climatic variability
using a range of measured and modelled metocean parameters (with time spans
varying from two to eight decades). With the exception of the mean monthly
wind speed, available metocean data do not indicate any statistically
significant changes outside seasonal and decadal cycles. No clear
relationship was found between changes in metocean conditions and rates of
shoreline change along the Sefton coast. High interannual variability and
the lack of long-term measurements make unambiguous correlations between
climate change and shoreline evolution problematic. However, comparison
between the North Atlantic Oscillation winter index (NAOw) and coastline
changes suggest increased erosion at times of decreasing NAOw values and
reduced erosion at times of increasing NAOw values. Erosion tends to be more
pronounced when decreasing NAOw values lead to a strong negative NAO phase.
At present, anthropogenic changes in the local sediment budget and the
short-term impact of extreme events are still the largest threat likely to
affect coastal flooding and erosion risk in the short- and medium-term.
Nevertheless, the potential impacts of climate change in the long-term
should not be ignored.
Citation: Esteves, L. S., Williams, J. J., and Brown, J. M.: Looking for evidence of climate change impacts in the eastern Irish Sea, Nat. Hazards Earth Syst. Sci., 11, 1641-1656, doi:10.5194/nhess-11-1641-2011, 2011.