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

Recent improvements in mapping of global population distribution makes it possible to estimate the number and distribution of people near coasts with greater accuracy than previously possible, and hence consider the potential exposure of these populations to coastal hazards. In this paper, we combine the updated Gridded Population of the World (GPW2) population distribution estimate for 1990 and lighted settlement imagery with a global digital elevation model (DEM) and a high resolution vector coastline. This produces bivariate distributions of population, lighted settlements and land area as functions of elevation and coastal proximity. The near-coastal population within 100 km of a shoreline and 100 m of sea level was estimated as 1.2 X 10(9) people with average densities nearly 3 times higher than the global average density. Within the near coastal-zone, the average population density diminishes more rapidly with elevation than with distance, while the opposite is true of lighted settlements. Lighted settlements are concentrated within 5 km of coastlines worldwide, whereas average population densities are higher at elevations below 20 m throughout the 100 km width of the near-coastal zone. Presently most of the near-coastal population live in relatively densely-populated rural areas and small to medium cities, rather than in large cities. A range of improvements are required to define a better baseline and scenarios for policy analysis. Improving the resolution of the underlying population data is a priority.

A global analysis of human settlement in coastal zones

https://oss.deltares.nl/documents/48999/59759/Roelvink_2009.pdf

Modelling storm impacts on beaches, dunes and barrier islands

Coastal zones constitute one of the most heavily populated and developed land zones in the world. Despite the utility and economic benefits that coasts provide, there is no reliable global-scale assessment of historical shoreline change trends. Here, via the use of freely available optical satellite images captured since 1984, in conjunction with sophisticated image interrogation and analysis methods, we present a global-scale assessment of the occurrence of sandy beaches and rates of shoreline change therein. Applying pixel-based supervised classification, we found that 31% of the world’s ice-free shoreline are sandy. The application of an automated shoreline detection method to the sandy shorelines thus identified resulted in a global dataset of shoreline change rates for the 33 year period 1984–2016. Analysis of the satellite derived shoreline data indicates that 24% of the world’s sandy beaches are eroding at rates exceeding 0.5 m/yr, while 28% are accreting and 48% are stable. The majority of the sandy shorelines in marine protected areas are eroding, raising cause for serious concern.

/pdf/the-state-of-the-world-s-beaches-23rvmtb7c1.pdf

The State of the World’s Beaches

Meteorology today : An introduction to weather, Climate, and the environment

Variability of shore and shoreline evolution

Genesis: generalized model for simulating shoreline change/Report 1

http://www.vliz.be/imisdocs/publications/41429.pdf

Beach nourishment projects, practices, and objectives - a European overview

This report describes a numerical model called GENESIS ( GENE ralized model for SI mulating S horeline change), developed for calculating shoreline change as caused primarily by wave action. The modeI is based on the one line theory, for which it is assumed that the beach profile remains unchanged, thereby allowing beach change to be described uniquely in terms of the shoreline position. As opposed to previous models based on the same concept, GENESIS is generalized in the sense that a simple user Interface allows the system to be applied to a diverse variety of situations involving almost arbitrary numbers, locations, and combinations of groins, jetties, detached breakwaters, seawalls, and beach fills. Other features included in the system are wave shoaling, refraction, and diffraction; sand passing through and around groins, and sources and sinks of sand. An overview of the modeling system is presented, and comparisons to analytic solutions as well as prototype situations are presented to demonstrate the capabilities of the system.

Hans Hanson

Papers

Variability of shore and shoreline evolution

Genesis: generalized model for simulating shoreline change/Report 1

Beach nourishment projects, practices, and objectives - a European overview

Genesis-A Generalized Shoreline Change Numerical Model

An analytical model to predict dune erosion due to wave impact