A KEY-ASSET TO ACT AGAINST COASTAL EROSION
The diversity of the coastal erosion indicators measurable from EO data, the monitoring frequency adapted to every end user expectation, and the accuracy achieved offer valuable and fundamental tools to support decision-makers in the mitigation of coastal hazards. Earth Observation also provide support for communicating on the effects of coastal protection measures and to anticipate consequences of planned actions, one-off events such as storms, or the effects of climate change.
For the first time in Europe, a consortium of multidisciplinary experts with adequate background in the use of satellite remote sensing for coastal erosion proposes an EO-based packaged service suited for every kind of coastal areas.
After proving that EO products provide relevant complementarity to field observations by providing new, reliable and crucial information lacking along many coastal areas around the world, the ESA Coastal Erosion initiative has probably definitely changed the game in the way to consider coastal erosion monitoring.
In the context of population growth, global warming and sea level rise, coastal erosion issues will be even more relevant in future, as both the frequency and strength of storm events are likely to increase causing billions of Euros of damages.
Unfortunately, this topic is not covered by any European directives (neither the Water nor the Marine Strategy); therefore, it is currently dealt with at the national levels (e.g. in France through the shoreline management policy) resulting in heterogeneous degrees of concern in different EU member States.
70% of the coastlines will face sea level rise within the average IPCC projections. It already raises geopolitical threats, impaires the territorial integrity of island states and countries mainly coastal.
The IPCC expectations are a massive climate-induced population migration by 2100, extreme hundred-year events will become annual, and ecological and economical threats: loss of invaluable ecosystems.
More than 200 million of European citizens live in coastal regions, representing 41% of Europe’s total population, and 33% live within 50 km from the sea (Eurostats, 2013). Coastal regions account for about 40% of European Union’s Domestic Gross Product with the maritime economy, tourism and yachting being the main parts of the total gross value. In addition, in 2004, the estimate of the current total value of the economic assets located within 500 m from the EU’s coastline, including beaches, agricultural land and industrial facilities, was 500 to 1,000 billion € (Eurosion, 2004; EEA, 2013).
According to the Eurosion project (Eurosion, 2004), 20 000 km of the coastline faced serious impacts in 2004. Most of the impact zones are actively retreating, including 2900 km that are already protected, whilst 4700 km are artificially stabilized. Erosion rates of 2 m per year are frequently recorded all over Europe. Thus, about 25% of the European coastline for which data is available is currently retreating. The issue is not restricted to European coasts, but is a global, worldwide threat.
The use of new technologies for shoreline monitoring has significantly increased during the past 20 years (airborne lidar topographic surveys, photogrammetry, in situ laser scanning) but their definitive adoption still depends on their cost to effectiveness ratio. At the same time, previous work has shown high-resolution (Pleiades-like) optical satellite remote sensing to be adequate and relatively cost-effective for detecting and monitoring shorelines over wide sandy areas on a yearly timescale (Lafon et al., 2010).
“Space for Shore” intends to unravel the remaining technical issues and to provide a large European end user community with prototyped products, that are based on the Copernicus Sentinel-1 and Sentinel-2 missions and, to a certain extent, on Third Party Missions.