Coastal sustainability for uncertain futures.

Agustin Sánchez-Arcilla, Joan Pau Sierra, Vicente Gracia, Manuel García-León, Jose Antonio Jiménez, César Mösso, Herminia Inmaculada Valdemoro

Chair(s): dr. Ciavola

Tuesday 30 june 2015

9:15 - 9:30h at Central America (level 0)

Themes: (T) Special session, (ST) Coasts at threat in Europe

Parallel session: 4H. Special Session: Coasts at Threat in Europe

In this paper we analyse the impact of future climate scenarios on the sustainability of geo-diverse coasts under heavy pressure of conflicting uses such as is the Catalan coast (Spanish coast in the Mediterranean). The paper will present the need to downscale future scenarios so that the coastal policy makers can rely on locally meaningful values. The available mean sea level, waves and storm surge projections will be presented and discussed, with emphasis on high end conditions to assess the coastal and harbour sustainability for a pessimistic combination of settings. We shall be comparing drivers, impacts and responses for the most vulnerable hot spots within our regional study case, with a coastal length of 700km and a variety of morphodynamic features and harbour geometries. This shall include two deltas and several artificial coastal stretches (including ports), where the natural dynamics have been prevented by a number of human interventions. The comparison of the behaviour under present conditions and the projected impacts will allow establishing an adaptation pathway where the various tipping points will be identified, assessing the effect of human interventions under future climatic conditions, particularly the extreme scenarios that go up to a plausible although unlikely 2.0 rise in mean sea level. The effect of natural accretion and defence mechanisms under future climates will also be included in the adaptive pathway, to show the role played by marine and riverine pulses in transporting sediments and how this natural power could be used to enhance the geomorphic resilience of our coast. In the discussion we shall present the feedback and relative contributions of future sea-levels, wave height, period and direction) and precipitation when projecting coastal impacts. Here we shall also discuss comparatively te downscaled results for the Catalan coast with other vulnerable tracts now being considered in ongoing EU research.