The Greek coast

The coastline of Greece is 15,000 km long (60% mainland, 40% islands). Four coastal types have been recognized (2): hard rock coasts (44%), soft rock or conglomerates cliff coasts with pocket beaches (14%), beach zones (36%), and mud coasts (6%).

The astronomical tide is generally less than 10 cm. Due to meteorological forcing (barometric pressure differences, wind and wave set up) sea level variation may exceed 0.5 m. The average annual significant wave height varies between 0.4 and 1.1 m (1).

Vulnerabilities - Current situation

Nearly one-third (28.6%) of the Hellenic coastline is eroding (mostly < 10 m over time periods of 20-30 years). Sediment supply to the coast has decreased strongly due to the construction of dams, river channelization and intense coastal development (1).

Vulnerabilities - Future situation

With respect to climate change, it was reported that in the case of a sea level rise up to 1.8 mm/year almost half of the Aegean coast would be moderately vulnerable and the remaining part highly vulnerable (3). For the case of a sea level rise of more than 3.5 mm/year, almost all the Hellenic Aegean coast would be highly vulnerable.

Island of Crete

With a length of 260 km and a width up to 60 km, Crete is the largest Greek island and one of the largest in the Mediterranean basin. The approximately 1,300 km long Cretan coastline shows various landforms, including rocky coasts/coastal cliffs and medium/coarse sediment beaches; about 15 % of coastline (in terms of length) is formed by sandy beaches (1).

Sea level rise may challenge the sustainability of the beach-based touristic sector through increasing beach erosion and the inundation/damage of related infrastructure (4). Therefore, a first (rapid) assessment of beach erosion was carried out to estimate the vulnerability of the beaches of Crete to sea level rise between now and the end of this century (5). This will help to develop appropriate adaptation measures that will ensure the long-term sustainability of beaches and their many ecosystem services and uses. The assessment was carried out for the beaches of Eastern Crete. With six different models (analytical and numerical) beach erosion was estimated under three scenarios of sea level rise: a low and high scenario of 0.26 and 0.82 m, respectively, between now and the period 2081 – 2100, and a ‘doom’ scenario of 1.86 m sea level rise in 2100 (5).

According to the results 80% of the examined beaches may retreat by more than 20% of their current maximum ‘dry’ width and about 16% by more than 50% under the low scenario of sea level rise between now and 2081 - 2100. Under the high scenario almost all of the examined beaches are predicted to retreat by more than 20% of their maximum current width, and about 72% by more than 50%. Part of the beaches may completely ‘drown’. The ‘doom’ scenario is worst case indeed: almost all of the examined beaches are predicted to retreat by more than 50% of their maximum current width. In fact, these results may be conservative, as other significant beach erosion factors (e.g., decreasing beach sediment supply) have not been considered (5). 

Adaptation strategies

Hard engineering structures that are used in Greece to protect the coast from eroding include seawalls, groins, breakwaters, revetments, flood embankments, placement of gabions and rock armouring. Approximately 15% of the eroding coastline is artificially protected. The most commonly used soft protection methods are beach nourishment, sediment recycling (transport of sediment from the down drift end of a beach back to its up drift end), and stabilization of coastal dunes with vegetation (1).

References

The references below are cited in full in a separate map 'References'. Please click here if you are looking for the full references for Greece.

1. Alexandrakis et al. (2013)
2. EUROSION project (2004), in: Alexandrakis et al. (2013)
3. Alexandrakis et al. (2010), in: Alexandrakis et al. (2013)
4. Snoussi et al. (2008), in: Monioudi et al. (2016)
5. Monioudi et al. (2016)