Since the IPCC Third Assessment Report (TAR), our understanding of the implications of climate change for coastal systems and low-lying areas (henceforth referred to as ‘coasts’) has increased substantially and six important policy-relevant messages have emerged. Coasts are experiencing the adverse consequences of hazards related to climate and sea level (very high confidence). Coasts are highly vulnerable to extreme events, such as storms, which impose substantial costs on coastal societies [6.2.1, 6.2.2, 6.5.2]. Annually, about 120 million people are exposed to tropical cyclone hazards, which killed 250,000 people from 1980 to 2000 [6.5.2]. Through the 20th century, global rise of sea level contributed to increased coastal inundation, erosion and ecosystem losses, but with considerable local and regional variation due to other factors [6.2.5, 6.4.1]. Late 20th century effects of rising temperature include loss of sea ice, thawing of permafrost and associated coastal retreat, and more frequent coral bleaching and mortality [6.2.5]. Coasts will be exposed to increasing risks, including coastal erosion, over coming decades due to climate change and sea-level rise (very high confidence). Anticipated climate-related changes include: an accelerated rise in sea level of up to 0.6 m or more by 2100; a further rise in sea surface temperatures by up to 3°C; an intensification of tropical and extratropical cyclones; larger extreme waves and storm surges; altered precipitation/run-off; and ocean acidification [6.3.2]. These phenomena will vary considerably at regional and local scales, but the impacts are virtually certain to be overwhelmingly negative [6.4, 6.5.3].

https://ro.uow.edu.au/cgi/viewcontent.cgi?article=1192&context=scipapers

Coastal systems and low-lying areas

Contributing Authors: Tarekegn Abeku (Ethiopia), Isabelle Cote (Canada), Mark Dyurgerov (USA), Martin Edwards (UK), Kristie L. Ebi (USA), Nicole Estrella (Germany), Donald L. Forbes (Canada), Bernard Francou (France), Andrew Githeko (Kenya), Vivien Gornitz (USA), Wilfried Haeberli (Switzerland), John Hay (New Zealand), Anne Henshaw (USA), Terrence Hughes (Australia), Ana Iglesias (Spain), Georg Kaser (Austria), R. Sari Kovats (UK), Joseph Lam (China), Diana Liverman (UK), Dena P. MacMynowski (USA), Patricia Morellato (Brazil), Jeff T. Price (USA), Robert Muir-Wood (UK), Peter Neofotis (USA), Catherine O’Reilly (USA), Xavier Rodo (Spain), Tim Sparks (UK), Thomas Spencer (UK), David Viner (UK), Marta Vicarelli (Italy), Ellen Wiegandt (Switzerland), Qigang Wu (China), Ma Zhuguo (China)

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Assessment of observed changes and responses in natural and managed systems

Understanding sea-level processes, such as ocean tides, storm surges, tsunamis, El Nino and rises caused by climate change, is key to planning effective coastal defence. Building on David Pugh's classic book Tides, Surges and Mean Sea-Level, this substantially expanded, full-colour book now incorporates major recent technological advances in the areas of satellite altimetry and other geodetic techniques (particularly GPS), tsunami science, measurement of mean sea level and analyses of extreme sea levels. The authors discuss how each surveying and measuring technique complements others in providing an understanding of present-day sea-level change and more reliable forecasts of future changes. Giving the how and the why of sea-level change on timescales from hours to centuries, this authoritative and exciting book is ideal for graduate students and researchers in oceanography, marine engineering, geodesy, marine geology, marine biology and climatology. It will also be of key interest to coastal engineers and governmental policy-makers.

Sea-Level Science: Understanding Tides, Surges, Tsunamis and Mean Sea-Level Changes

As reflected in the ecosystem approach, conservation strategies for the natural environment are responding to society's needs and the changing climate. Ecosystem assessments, particularly the Millennium Ecosystem Assessment and the UK National Ecosystem Assessment, have reviewed the benefits that society gains from the natural environment, but they under-represent and undervalue the contribution of geodiversity. Geodiversity underpins and delivers many vital ecosystem services, informs their management and is an important element of natural capital. This includes the application of knowledge of physical processes and evidence from Quaternary archives of recent environmental change to help future-proof ecosystems and their services. Key principles include working with natural processes, based on understanding their spatial and temporal dynamics, and adopting where possible soft engineering practices to enable multiple benefits for nature and society. The ecosystem approach and the need for climate change adaptation require more integrated approaches to geodiversity, biodiversity and landscape conservation and management to enable a more sustainable future. Engaging with these issues will also demonstrate the wider relevance today of geodiversity and geoconservation. Contributing successfully in these critical areas requires closer partnership working, both across the geoscience and geoconservation communities, and with other sectors of nature conservation, policy makers, planners and communities, as well as other disciplines. Geoscience has an essential contribution to make in addressing knowledge gaps recognised in ecosystem assessment and in implementing robust solutions to broader environmental, economic and social issues.

Geodiversity and the ecosystem approach: the contribution of geoscience in delivering integrated environmental management

Social justice in coastal erosion management: The temporal and spatial dimensions

Coastal steepening potentially presents an array of management issues in the form of financial implications of sea defence degradation, increased risk posed to the hinterland as wave attenuation is reduced, 'coastal squeeze' and statutory requirements in the light of the Habitats Directive. The extent to which coastal steepening has occurred throughout England and Wales has been investigated through use of a GIS and dataset based on historical Ordnance Survey map information. Data were collected along 1084 selected profile lines, positioned so as to be geomorphologically representative of the coast. Features recorded from each map year included the positions of mean high water (MHW) and mean low water (MLW), the relative movements of which infer changing intertidal gradients. The results presented in this paper are on a subject and scale not previously published. It is revealed that 61% of the coastline studied has experienced a tendency towards steepening. Of the remainder, 33% has flattened, and 6% has experienced no rotational movement. This tendency towards steepening has been the dominant movement on each of the west, south, and east coasts.

J A Taylor

Papers

A macroscale analysis of coastal steepening around the coast of England and Wales