ArticlePDF Available

Abstract and Figures

This paper studies climatic drivers (air and water temperature, precipitation rates, river discharge, sea level and storm patterns) in four Mediterranean regions: the Catalan-Valencia Coast (Spain), the Oran (Algeria) and Gabès (Tunisia) Gulfs and the western Nile Delta (Egypt). The paper also considers the potential hazards that these drivers can induce. It first analyses climatic trends in the drivers, taking into account the available time series of recorded and simulated meteo-oceanographic data from different sources. Next, it presents the general framework to assess biogeophysical hazards (flooding, erosion, droughts and water quality), followed by a simple and yet robust evaluation of those hazards for the four studied coastal sites. Assuming climate change projections under different scenarios and considering the observed trends in drivers, the resulting erosion rates due to sea-level rise and wave storm effects have been estimated. The Nile and Ebro Deltas, together with the Oran Gulf, are more vulnerable than the Gulfs of Valencia and Gabès. Regarding water quality in terms of (a) precipitation and dissolved oxygen in the water column and (b) sea surface temperature, the results show that the most vulnerable zones for the projected conditions (a) are the Gulfs of Oran, Valencia and Gabès, while the Nile Delta is the region where the decrease in water quality will be less pronounced. For the projected conditions (b), the most vulnerable zone is the Ebro Delta, while the impact in the other three cases will be smaller and of comparable magnitude. Finally, the overall future impact of these hazards (associated to climatic change) in the four sites is discussed in comparative terms, deriving some conclusions. KeywordsMediterranean–Coastal hazards–Climatic drivers–Erosion–Flooding–Water quality
Content may be subject to copyright.
Climatic drivers of potential hazards in Mediterranean coasts
´nchez-Arcilla Cesar Mo
Joan Pau Sierra Marc Mestres Ali Harzallah
Mohamed Senouci Mohamed El Raey
Received: 10 March 2010 / Accepted: 27 November 2010 / Published online: 17 December 2010
ÓSpringer-Verlag 2010
Abstract This paper studies climatic drivers (air and
water temperature, precipitation rates, river discharge, sea
level and storm patterns) in four Mediterranean regions: the
Catalan-Valencia Coast (Spain), the Oran (Algeria) and
`s (Tunisia) Gulfs and the western Nile Delta (Egypt).
The paper also considers the potential hazards that these
drivers can induce. It first analyses climatic trends in the
drivers, taking into account the available time series of
recorded and simulated meteo-oceanographic data from
different sources. Next, it presents the general framework
to assess biogeophysical hazards (flooding, erosion,
droughts and water quality), followed by a simple and yet
robust evaluation of those hazards for the four studied
coastal sites. Assuming climate change projections under
different scenarios and considering the observed trends in
drivers, the resulting erosion rates due to sea-level rise and
wave storm effects have been estimated. The Nile and Ebro
Deltas, together with the Oran Gulf, are more vulnerable
than the Gulfs of Valencia and Gabe
`s. Regarding water
quality in terms of (a) precipitation and dissolved oxygen
in the water column and (b) sea surface temperature, the
results show that the most vulnerable zones for the pro-
jected conditions (a) are the Gulfs of Oran, Valencia and
`s, while the Nile Delta is the region where the
decrease in water quality will be less pronounced. For the
projected conditions (b), the most vulnerable zone is
the Ebro Delta, while the impact in the other three cases
will be smaller and of comparable magnitude. Finally, the
overall future impact of these hazards (associated to cli-
matic change) in the four sites is discussed in comparative
terms, deriving some conclusions.
Keywords Mediterranean Coastal hazards Climatic
drivers Erosion Flooding Water quality
During this century, society will increasingly be confronted
with impacts of global change, such as pollution and land
uses (Metzeger and Schro
¨ter 2006). A ‘‘robust’’ illustration
for the driving climatic terms is provided by the global
average surface temperature, projected to increase by
1.1–6.4°C by 2100 (Bates et al. 2008).
There is a general agreement that impacts of climate
change are more likely to result from altered climate
A. Sa
´nchez-Arcilla (&)C. Mo
¨sso J. P. Sierra M. Mestres
Laboratori d’Enginyeria Marı
´tima, Universitat Polite
`cnica de
Catalunya, Jordi Girona 1–3, Edifici D1 Campus Nord, 08034
Barcelona, Spain
A. Sa
´nchez-Arcilla C. Mo
¨sso J. P. Sierra M. Mestres
Centre Internacional d’Investigacio
´dels Recursos Costaners,
Jordi Girona 1–3, Edifici D1 Campus Nord,
08034 Barcelona, Spain
A. Harzallah
Institut National des Sciences et Technologies de la Mer, 28,
rue du 2 mars 1934, 2025 Salammbo, Tunisia
M. Senouci
Membre du Groupe Intergouvernemental sur l’Evolution du
Climat (IPCC), Association de Recherche Climat
Environnement, ARCE, BP 4250, Ibn Rochd,
31037 Oran, Algeria
M. El Raey
Alexandria University, Arab Academy of Science and
Technology and Maritime Transport, El-Guish Road, El-Shatby,
Alexandria 21526, Egypt
Reg Environ Change (2011) 11:617–636
DOI 10.1007/s10113-010-0193-6
variability and extremes than from changes in mean trends
(Goubanova and Li 2007). Any intensification and/or
increase in the number of extreme events are likely to have
disastrous socioeconomic implications on developed and
developing countries (Changnon 2003). Indeed, global
climate modelling experiments suggest that climate
extremes may become more severe under increased
greenhouse concentrations in most regions of the globe
(Kharim and Zwiers 2000; Voss et al. 2002).
It is also expected that global warming will aggravate
disease and pest transmission. Stronger or more frequent
extremes (storms, floods, etc.) associated with climate
change would cause physical damage, population dis-
placement and adverse effects on food production, fresh-
water availability and quality. The combination of these
elements would also increase the risks of infectious and
vector-borne diseases, particularly in developing countries
such as those of the southern Mediterranean shores (Moreno
2006). Primary sectors, such as agriculture and forestry,
will be more sensitive to climate change than secondary
and tertiary sectors, such as manufacturing and retailing.
Nevertheless, some tertiary sectors can also be affected.
For example, climate is a crucial resource for tourism, so
climate variations would have a profound impact on tourism
producing shifts in the pattern of demand (Hamilton and Tol
2007), with direct implications on tourist areas such as
Mediterranean shores.
Climate change also has the potential to significantly
alter the conditions for crop production due to changes in
the precipitation regime that would affect the yield distri-
bution considerably (Torriani et al. 2007). Climate change
is expected to have positive impacts only in northern
countries, implying that areas of crop suitability may
expand northwards (Olesen et al. 2007). Southern areas
(such as Mediterranean coastal countries) will probably
have to face increasing water shortage and incidence of
extreme adverse events, reducing crop yields and the area
for cropping. Moreover, the higher temperatures are likely
to increase crop water requirements and more irrigation
water will be needed per hectare (Rodrı
´az et al.
2007). Different studies on the impacts of climate change
on crop yields have been performed at different levels
(Iglesias et al. 2000; Saarikko 2000; Chen et al. 2004; Parry
et al. 2004; Trnka et al. 2004; Reidsma et al. 2009), but the
overall conclusion does not vary with scale, although there
is a sharp spatial variability across the Mediterranean basin.
Low-lying coastal regions, such as deltas or bays, are
subject to a series of driving factors that dynamically
interact with the active (as a function of the considered
time-scale) geo and ecosystems. These areas are specially
sensitive to changes in climatic drivers. In particular, del-
taic systems show the consequences of many kinds of
human-induced changes such as variations in river liquid
discharge (flow regulation) or in river solid discharge
(erosion control in the catchment basin or barrier effect of
dams). Affected by changes in relative sea-level rise (SLR)
and in atmospheric and marine factors (precipitation, wind,
storminess), deltaic systems are, thus, highly sensitive
ecosystems subject to the interactions of river, sea, land
and atmospheric factors (Sa
´nchez-Arcilla and Jime
1997). Coastal bays are also influenced by meteo-oceano-
graphic factors as well as natural or man-made boundaries,
which can act as a barrier constraining water circulation
and, thus, affecting water quality (Sa
´nchez-Arcilla et al.
2007). The associated changes in land use have become a
major driver and indicator of environmental change. This
can be illustrated by conflicts between past and present
land uses or between economic and ecologic priorities (Hill
et al. 2008) and also by the large areas of the European
Mediterranean that are affected by land degradation or
In coastal zones, flooding occurs due to storm surges
generated by meteorological forcing, mainly due to the
tangential surface wind stress on the ocean surface and the
atmospheric pressure gradients associated with the weather
systems (Kurian et al. 2009). This, combined with
anthropogenic global warming, is expected to contribute to
an increase in flooding frequencies during this century and
beyond. Sea-level rise will increase the vulnerability of
coastal populations and ecosystems, via permanent inun-
dation of low-lying regions, inland extension of episodic
flooding, increased beach erosion and saline intrusion of
aquifers (Cooper et al. 2008). Finally, wind waves are
another component of Mediterranean coastal systems, and
changes in their characteristics can have important conse-
quences on off-shore activities such as ship traffic and,
even more critical, on coastal uses and resources (Lionello
et al. 2008a).
In this paper, the main climatic drivers affecting coastal
areas in the Mediterranean basin and their potential hazards
have been analysed. The study focuses on four areas of the
Mediterranean region, which represent a variety of features
and coastal environments that can be found in this region.
The diversity of environments is also reflected in the
available data sets, limited in time, restricted in spatial
coverage and showing important gaps that shall be high-
lighted in the paper.
Study area
The aim of this work is to characterize drivers and hazards
for typical Mediterranean conditions. Because of that, four
areas (representative of the Mediterranean coastal envi-
ronment and particularly sensitive to climate change) have
been selected. They all fulfil some minimum requirements
618 A. Sa
´nchez-Arcilla et al.
for observational evidence to allow performing an initial
analysis at climatic scales. The four areas in a west-east
direction are as follows: the Spanish NW Mediterranean
Coast (Spain), the Gulf of Oran (Algeria), the Gulf of
`s (Tunisia) and the Alexandria and West Nile Delta
area (Egypt). Their locations are shown in Fig. 1.
The four cases present a typical Mediterranean climate,
but each area has some distinctive features. The studied
part of the Spanish Coast, in the north-western Mediterra-
nean, is located in front of the Balearic Islands, stretching
from the Creus Cape in the north to La Nao Cape in the
south, with a coastal length of about 750 km. Its location,
together with the local topography, exert a significant
control over the wind climate, which is characterized by
low to medium average winds, although some synoptic
events are responsible for strong winds in this region
´nchez-Arcilla et al. 2008a). Moreover, this area also
presents some special features that determine the wave
climate, being the most important the short fetches (due to
the presence of the Balearic Islands), the high wind vari-
ability in time and space (Mo
¨sso et al. 2007) and the wave
calms during the summer and energetic storms from
October to May. This wave climate has a very defined
seasonal structure with yearly averaged significant wave
heights lower than 1 m (Garcia et al. 1993; Sierra et al.
2002). As a result of the oblique wave approach for the
more energetic E-NE storms, long shore sediment transport
shows a net S-SW component (Sa
´nchez-Arcilla et al.
As most of the Mediterranean coast, this is a microtidal
environment and, according to different tide gauges located
in the area, the maximum spring tide range observed is of
about 40 cm. Storm surges are also common, with inten-
sities up to 1.0 m for typical storm conditions (Sa
Arcilla et al. 2008b). In some areas, there is also subsi-
dence, as for instance in the Ebro Delta, where the average
rate is between 1.5 and 3.0 mm per year (Sa
et al. 1996; Somoza et al. 1998).
The second analysed case, the Gulf of Oran, located in
western Algeria, is delimited by the Aiguille Cape in the
east and the Falcon Cape in the west, and it is about 50 km
wide. This gulf encompasses, in its western part, from the
port of Oran to the Mers El Kebir, and it is characterized by
high and escarped cliffs, going from 10 to almost 30 m in
height. In the eastern part, the coast presents smaller cliffs,
interrupted by small and narrow beaches.
This area has a semi-arid Mediterranean climate, with
mild and wet winters and hot and dry summers. The
average rainfall is of about 390 mm/year (varying from
2 mm in July to 120 mm in December). This sunny region,
with more than 3,300 h of sunshine per year, has monthly
average temperatures ranging from 12°C in January to
29°C in August (Chegaar and Chibani 2001). The wind
regime features 6% of calm periods and an average wind
velocity of 3.6 m/s (Merzouk 2000), with monthly average
wind speeds between 3 m/s (December) and 4.6 m/s
(April) (Mahmoudi et al. 2009).
Due to the prevailing currents in the area, the Gulf of
Oran receives waters of Atlantic origin (Millot 1987). The
circulation seems to be turbulent along the Algerian Coast,
and these turbulences favour the dispersion of eventual
pollution sources and allow a relative important primary
productivity (Millot et al. 1997).
The third studied zone, the Gulf of Gabe
`s, is a shallow
eastward-facing embayment area located in the Tunisia
Coast. It is 100 km long and 100 km wide, with depths
typically ranging from 20 to 50 m (Sammari et al. 2006). It
is bordered by a subdued topography formed mainly by
low plateaus (20–70 m) and plains (1–5 m), and it is
characterized by an arid Mediterranean climate, with an
average rainfall varying from 250 mm/year in the north to
100–150 mm/year in the south, although the rainfall rate is
highly irregular (Oueslati 1992).
The Gulf of Gabe
`s is one of the few Mediterranean
regions where astronomic tides are relatively important,
with a semi-diurnal pattern and spring tidal range of
Fig. 1 The Mediterranean
basin showing the four case
studies selected for this work
Climatic drivers of potential hazards in Mediterranean coasts 619
2.0–2.3 m (Morhange and Pirazzoli 2005). This is because
of resonance phenomena in the area which act to amplify
tidal levels (Sammari et al. 2006). On the other hand, wave
storms in the Gulf of Gabe
`s are generally low energy
events, because of the shallowness of the broad continental
shelf and the important meadows of phanerogams. The
wave energy is also bounded by the low wind velocities
and, in some positions, the limited fetch (Oueslati 1992),
which restricts the effect of the stronger easterly winds.
This area is also characterized by weak currents, with high
temperature (13.2–26.5°C) and high salinity in summer
(37.5–39.25%) (Pe
´rez-Domingo et al. 2008), although
lower salinities (37.3–37.5%) have been detected in the
region in other seasons and have been attributed to the
presence of Modified Atlantic Water (Be
´ranger et al. 2004;
´et al. 2005; Poulain and Zambianchi 2007; Drira
et al. 2008; Bel Hassen et al. 2009).
In the last years, this area has suffered high anthropic
pressures due to urban and industrial activities (Drira et al.
2008), experiencing a substantial proliferation of microal-
gae and, particularly, toxic dinoflagellates (Turki et al.
2006). As a consequence, fish resources in the Gulf of
`s (which represent 65% of the national fish production
in Tunisia) have declined, associated to the degradation of
seagrass meadows.
Finally, the fourth studied environment, the West Nile
Delta, is located in Egypt, in the eastern Mediterranean and
at the mouth of one of the world’s longest rivers
(6,690 km). The annual average water discharge averaged
84 billion m
during the twentieth century. More than 80%
of the Nile River total discharge occurs from August to
October, while about 20% is distributed during the
remaining 9 months (Stanley and Warne 1998).
This delta is located in a hyperarid region, with tempera-
tures over 30°C in July and mean annual precipitation
ranging from 100 to 200 mm. The deltaic plain encom-
passes about 22,000 km
, and its coast is about 225 km
long. It is characterized by a very low tidal range (spring
tides average 30–40 cm), N-NW offshore winds that are
active during most of the year, and a large-scale counter-
clockwise circulation pattern that drives water masses
eastward. The offshore surface (geostrophic) eddy veloci-
ties can exceed 0.25 m/s (Stanley and Warne 1998). Pre-
dominant waves feature an oblique approach, generating
longshore currents with velocities from 20 to 50 cm/s and
occasionally exceeding 100 cm/s. Storm waves with heights
of 1.5–3 m approach the coast from the northern quadrant
(commonly from the north-west), eroding and displacing
sediment eastwards (Stanley 1989; Stanley et al. 1998).
The Nile Delta is also experiencing relative sea-level
rise due to land subsidence. In the northern delta, this
happens at a rate between 1 and 5 mm per year (Emery
et al. 1988; Stanley 1988,1990; Stanley and Goodfriend
1997). Moreover, since the construction of the High Dam
at Aswan in 1964, less than 2% of sediment bypasses this
dam, and about 100 million tons of sediments per year
accumulate in the southern part of Lake Nasser reservoir.
As a consequence, less than 10% of the former Nile River
potential sediment load is now delivered to the Mediter-
ranean coast (Stanley and Warne 1998).
General framework
One of the most robust indicators of climate change is air
temperature. Most of Europe has revealed increases in
surface air temperatures during the twentieth century. This
warming has been largest over north-western Russia and
the Iberian Peninsula (Nicholls et al. 1996), suggesting that
in Europe the balance (in terms of implications) of climate
change will be more negative in southern and eastern
countries (Maracchi et al. 2005).
In the last decades, extreme events registered in the
Mediterranean basin have shown an increase in heavy
precipitations and a raise of extreme temperatures (Sa
et al. 2004; Giorgi et al. 2004). Present climate models
indicate a decrease in precipitation levels during the
twenty-first century (Gibelin and De
´2003), mainly
during the summer months (Rowell 2005), with the central
and south Mediterranean being one of the regions most
affected by the precipitation decrease. This will exacerbate
drought episodes, land degradation and desertification,
particularly for the East-Mediterranean (Ko
¨rner et al. 2005;
Vicente-Serrano 2007). A pronounced warming is also
projected, being maximum in the summer season with a
greater occurrence of high temperature events (Giorgi and
Lionello 2008).
Global low-frequency sea-level trends are dominated by
the steric component, and the associated ocean volume
increase (Levitius et al. 2000; Calafat and Gomis 2009).
However, at a regional scale, atmospheric pressure and
wind effects can also play a key role (e.g. Gomis et al.
2008) such as it happens for the Mediterranean region.
Wind-generated waves are the more energetic driving
term among all meteo-oceanographic factors, given the
limited tidal range in the Mediterranean. The available
observational series span less than three decades, which
suggests the use of numerically generated series. However,
the hindcast fields should be used with care since the
accuracy of predicted waves is significantly smaller than
for open sea conditions (Be
´ranger et al. 2004; Cavaleri and
Bertotti 2006).
Some analyses suggest a milder future wave storm cli-
mate, being the significant wave height reduction linked to
620 A. Sa
´nchez-Arcilla et al.
the diminished ocean surface winds and storm activity. A
reduction in low-pressure centre intensity is consistent with
the overall decrease in precipitation and northward dis-
placement of storm tracks, which most models indicate for
the Mediterranean area (Lionello et al. 2008a). Neverthe-
less, within the last decades, the NW Mediterranean has
experienced some of the most severe storm events ever
recorded in the area (Sa
´nchez-Arcilla et al. 2008a).
Sea level
Sea level rise is an important indicator of climate change,
with great relevance in squeezed coastal regions, such as
those of the Mediterranean, for flooding, coastal erosion
and the loss of low-lying areas. Relative sea-level rise
increases the likelihood of storm surges, enforces landward
intrusion of salt water and endangers coastal ecosystems
and wetlands. Apart from natural ecosystems, coastal areas
often feature important managed ecosystems, economic
sectors and major urban centres. Thus, a higher flood risk
increases the threat of loss of life and property as well as of
damage to protection measures and infrastructures. This, in
turn, should result in a degradation of coastal functions
such as recreation, transport.
A change in relative mean sea level (MSL) at the coast
may have various origins. It can be caused by the vertical
movement of the land itself. This applies to the Mediter-
ranean basin, which is located on the boundary of an active
geological plate, so that any global sea-level rise induced
by climate change may be locally accentuated or mini-
mized by tectonic movements. Relative MSL can also arise
from local sea-level changes due to variations in prevailing
winds and ocean currents or from by a change in the vol-
ume of the world’s oceans, mainly controlled by
It is generally accepted that the global sea level has
increased between 10 and 25 cm over the past 100 years
(e.g. Raper et al. 2001), and it is expected that the rise will
not only continue in the near future, but it will probably
also accelerate, although the range of predictions and
models is so large that precise forecasting is not possible.
Nicholls and Hoozemaans (1996) point out that the sea
level might rise between 0.2 and 0.9 m by the year 2100,
being the best estimates in the order of 0.5 m. In the past
100 years, European and global average sea level has risen
by 10–20 cm with a central value of 15 cm (IPCC 2001).
Currently, the sea level at Mediterranean coasts is rising at
a rate of 1.0 mm/year (Marseille), 1.3 mm/year (Genova or
Trieste), to 2.6 mm/year (Venice), which is close to the
global average (Liebsch et al. 2002). It is likely that the
observed trend in sea-level rise over the past 100 years is
mainly attributable to an increase in the volume of ocean
water as a consequence of global warming. The local
variations could be explained by some of the other pro-
cesses mentioned above. In what follows, we shall discuss
the trends in the Catalan (Spain) Coast and Gabe
`s Gulf.
There is no conclusive evidence for Oran and the case of
the Nile Delta will be discussed at the end of this section.
The relative sea level in the Spanish Mediterranean
Coast and Gulf of Gabe
`s do not present a common or well-
defined pattern. The available data in the Spanish Coast
case consist of hindcasted storm surge data (HIPOCAS)
from 1958 to 2001 (Ratsimandresy et al. 2008) and
observations of the residual tide within the ports of Bar-
celona and Valencia from 1992 to date. For the Gulf of
`s case, there are only observed series since 1999.
For the Spanish coastal case, storm surge simulations
(Fig. 2a) suggest that the relative sea level is slightly
decreasing during the considered time span. The average
decrease in surge intensity is of about -0.54 m per decade.
The observations also suggest a fall in mean sea level of
-0.04 m per year, although the registered time series are
too short to allow any final conclusion. In both cases, it is
assumed that the land remains at a steady level since that is
the conclusion obtained from recent geological studies
(Somoza et al. 1998). The trend in mean sea level derived
from observations is, however, so small dependent on the
considered time-scale (due to the shortness of the series)
that the more robust conclusion is that it is almost steady.
In the case of the Gulf of Gabe
`s, the observed data,
provided by the Tunisia Hydrographic and Oceanographic
Center, suggest that the relative sea level is rising at a rate
of 2.6 cm per decade (Fig. 2b). These results are consistent
with altimetry data that show an increase in sea level of
2.1 cm per decade. Notably, for the Spanish case, if only
modelled data from 1992 to 2001 are considered (coin-
ciding temporarily with some of the observed data), they
suggest an increase in storm surge of 1.75 cm per decade.
This suggests an increase in mean sea level at both loca-
tions and illustrates the sensitivity of the relative sea-level
values to the selected time and space intervals.
Precipitation rates
Changes in average precipitation can have potentially far-
reaching impacts on ecosystems and biodiversity, agricul-
ture (food production), water resources and river flows.
Global climate model simulations indicate that there shall
be a decrease in yearly averaged values but that the return
period for heavy rainfall events may decrease (Lionello
et al. 2002). This change in precipitation patterns, associ-
ated to a decreasing mean and an increasing variance in the
corresponding probability function, should lead to an
intensification of flooding during the rainy period, parti-
cularly for low-lying coastal areas. This will be accompa-
nied by more frequent and severe drought periods, more
Climatic drivers of potential hazards in Mediterranean coasts 621
frequent land slides and increased soil erosion. Floods and
droughts can even occur in the same region in different
seasons of the same year (e.g. a region may be exposed to
drought in spring and summer and be flooded in autumn).
Brunet et al. (2007) have studied the changes in precipi-
tation extremes within Spain (from the beginning of the
twentieth century) indicating that there is a tendency
towards more intense rainy days and increases in heavy
precipitation during the twentieth century, a behaviour
consistent with a warmer planet.
Decreasing precipitation trends will mean reductions in
water quality and availability over the four regions.
Drought periods are likely to become more frequent as the
probability of dry days and the length of dry spells
increase. The more frequent extreme precipitation events
will intensify the hydrological cycle and the risk of extreme
flooding and erosion. Most scenarios suggest an increase in
the frequency of extreme events and, in particular, of
droughts and flooding in the western Mediterranean. The
potential coastal impact of modified precipitation rates is
largely associated to the supply of riverine sediment to
counter the enhanced land loss and erosion induced by the
sea-level rise and increased storminess. Therefore, and
taking into account that river sediment transport takes place
only when the river flow exceeds a given threshold, it is the
time distribution of extreme precipitation events that is of
interest, rather than a mean (e.g. yearly) precipitation trend.
Nevertheless, the real influence on the coast of larger
rainfall rates is limited due to the effective decoupling of
riverine systems from the coastal environment, because of
the intensive regulation of river flows by dams. In recent
works, it has been estimated that more than 90% of the
Annual Storm Surge (Hipocas Data) in cm
Mean Sea Level
Hipocas Data
Mean Sea Level Hipocas
Linear Trend from 1990-2001
Linear Trend from 1958-2001
1999 2000 2001 2002 2003 2004 2005 2006 2007 2008
Monthly Storm Surge (Observed Data) in cm
Mean Sea Level
Observed Data
Sea Level Sfax
Linear Trend
Fig. 2 Storm surge at the Ebro
Coast in Spain (hindcasted data)
and at the Gabe
`s Gulf (observed
data). Considering the hindcast
time series (1954–2001), there
is a slight decreasing trend at
Ebro, while if we only look at
the last decade of data, there is
an increasing trend, consistent
with the observations of mean
sea level from Gabe
622 A. Sa
´nchez-Arcilla et al.
sediment transported by, e.g., the Ebro River became
trapped in the numerous reservoirs built along its course.
The reduction is nearly complete for bed load (the only one
providing beach sized material) but is also affects sus-
pended and wash loads (Marin
˜o1992; Iba
˜ez et al. 1996;
´nez 2005). The same applies to the Nile, as mentioned
in the previous section.
Precipitation data coverage in the Mediterranean is quite
heterogeneous, and the derived trends are uncertain,
because measurement techniques have changed during the
twentieth century. However, it is clear from the recorded
data that precipitation, in terms of standardized anomalies
(e.g. the case of the Catalan Coast), shows a large vari-
ability typical of the Mediterranean climate, preventing a
clear identification of sub-periods with differential beha-
viour (Fig. 3).
Precipitation patterns in the four studied sites (Fig. 3)
show the characteristic variability of the Mediterranean,
with negative or positive trends depending on location.
There are inverse trends between Barcelona and Ebro Delta
(200 km apart) in the Spanish case or between Gabe
`s and
Oran and important decadal shifts in the West Nile Delta.
Despite the great variability, any changes in precipitation
patterns will have a direct influence on the studied coasts.
Precipitation rates in the 4 cases show a large variance and
no significant commonalities. In the Spanish case, the
studied stations (Fabra in Barcelona from 1914 to 2008 and
Ebro Delta, from 1906 to 2008) show an opposite trend, the
yearly mean decreasing in Fabra and increasing in Ebro
Delta through the observed period, and without similarities
in the annual distribution of rainfall. Table 1summarizes
the different dry and wet periods recorded at the analysed
The registered series show some commonalities among
sites, such as the dry period around 1925 in the Catalan
Coast and Gulf of Gabe
`s or the rainy interval around
1970–1975 in the Catalan Coast, the Gulf of Oran and
`s. There are no clear and statistically significant
trends, nor any common sustained patterns, for the 4
studied sites. Moreover, the Gabe
`s plot (where data pro-
vided by the Ministery of Agriculture and Water Resources
of Tunisia from other stations are included) illustrates the
high-level variability at a local scale (less that 200 km)
typical of Mediterranean shores.
Precipitation Anomaly
Ebro Std Precip Anomal.
GaussianSmooth (3)
Ye a r
Precipitation Anomaly
Oran Std Precip Anomal.
GaussianSmooth (3)
Precipitation Anomaly
Gabès Std Precip Anomal.
GaussianSmooth (3) Gabès
GaussianSmooth (3) Sfax
GaussianSmooth (3) Jerba
190519101915192019251930193519401945195019551960196519701975198019851990199520002005 1925 1930 1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005
1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010
Ye a r
Precipitation Anomaly
West Nile Delta Std Precip Anomal.
GaussianSmooth (3)
Fig. 3 Precipitation rates, expressed as anomaly over standard
deviation, at the Spanish NW Mediterranean Coast (a), Gulf of Oran
(b), Gulf of Gabe
`s(c) and West Nile Delta (d). The Gulf of Gabe
plot includes time series from and from the Tuni-
sian Ministry of Agriculture and Water Resources, illustrating the
high level of local variability
Climatic drivers of potential hazards in Mediterranean coasts 623
This observational evidence agrees with predicted
regional changes (Lionello et al. 2008b), which suggest a
decrease in average precipitation together with an increase
in rainy events during fall/winter. These trends may be
different for the northern Mediterranean shore, particularly
in the region of Alpine influence, which may even expe-
rience an increase in precipitation.
Even assuming that the frequency and intensity of storms do
not vary due to climate change, the return period of extreme
water levels induced by storm surges at the coast will be
reduced because of relative sea-level rise (Sa
et al. 2008b). This will eventually lead to a larger frequency
of flooding events in coastal low-lying areas. Particularly
vulnerable to this effect will be deltaic areas and coastal
lagoons (Sa
´nchez-Arcilla and Jime
´nez 1994), where the
combined effects of subsidence plus low topography will
induce flooding and enhanced erosion (Fig. 4).
Any variations in wave and storm characteristics will
play a critical role in determining the coastal impact of
climate change, since the present shoreline configuration is
in dynamic equilibrium with today’s meteo-oceanographic
patterns. Incident waves with larger average heights will
result in stronger longitudinal and return currents, which
will eventually lead to enhanced coastal sediment transport
and erosion rates. A further contribution to coastline ero-
sion can result from the increased frequency of moderate
storms, since the coast will not have enough recovering
time between storm events.
However, the exact response of the coast to these storms
depends not only on the energy of the event, but also on the
particular features of the storm, such as duration, wave
period or steepness (Sa
´nchez-Arcilla et al. 2008a). Related
flooding (due to storm surge and wave-breaking) is the
single most destructive type of natural disaster that strikes
humans and their livelihoods around the world (Ismail-
Zadeh and Takeuchi 2007), and this also holds true for
Mediterranean coasts.
The storms considered in this study have been defined
by two different criteria, in terms of meteorological con-
ditions for the Gulf of Oran and in terms of wave
conditions for the Spanish Mediterranean Coast (Bolan
et al. 2004). This provides the widest possible coverage of
meteo-oceanographic conditions for the available obser-
vations. The main result is the large variability, in time and
space, characteristic of Mediterranean conditions, which
are essentially torrential. The average number of observed
meteorological storms in the Gulf of Oran from 1950 to
2007 does not present significant changes throughout the
observation period, though there are more extremes since
1970. More specifically, autumn storms have increased
their frequency by about 10% since 1975. This increase is
related to recent floods in the north-western region of
Table 1 Summary of rainy and
drought periods in the four
study cases
Site Rainy period Drought period
Spanish Coast (Barcelona) (1970–1993) (1994–2008)
Spanish Coast (Ebro) (1936–1949) (1956–1976) (2001–2008) (1907–1932) (1976–2000)
`s (1917–1922) (1948–1997) (1907–1916) (1923–1948)
Oran (1926–1926) (1948–1976) (1937–1947) (1997–2007)
West Nile Delta (1962–1969) (1988–2009) (1970–1987)
Fig. 4 Storm impact in the Ebro region and, in particular, in the
Trabucador Beach (top-left). Breaching after the impact of the
October 1990 storm (top-right). Breaching after the November 2001
storm (bottom)
624 A. Sa
´nchez-Arcilla et al.
In the Spanish case (Fig. 5), the annual number of
moderate and severe wave storms throughout the obser-
vation period (1990–2006) presents an opposite trend: a
decrease in the number of severe storms, while there is an
increase in the number of moderate storms.
Regarding the actual Hs magnitude, the observed data
series are too short (Fig. 6) to provide any definite con-
clusion. The hind-cast values, on the other hand, suggest an
increase at most stations, as illustrated in Fig. 6for the
`s and Catalan Coasts. The Spanish data come from the
HIPOCAS project and have been supplied by Puertos del
Estado (Ministry of Public Works). The Tunisian data
come from the Direction Ge
´rale des services Aeriens et
Maritimes, Ministe
`re de l’Equipement et l’Habitat.
The average duration of the studied moderate storms is
fairly constant, while the corresponding value for severe
storms has shown an increasing trend during the last dec-
ade (Fig. 5). The directional distribution of incident waves
shows also large variations, as expected for the irregular
topo-bathymetric characteristics of Mediterranean coasts.
This is illustrated with data from the Spanish coast (Fig. 7).
In the sector around Barcelona, the more energetic waves
come from the East, corresponding to the longest fetch,
since this part of the coast is sheltered from Northern wave
components. The Ebro Delta Coast, in the middle of the
Spanish case, shows frequent wave events from the East
and North-West. The East corresponds to the same storms
as for the Barcelona sector, while the NW (Mistral) waves
are associated to winds from that direction blowing down
the valley of the Ebro River. The most southern Spanish
location (Cullera Bay) shows a predominance of NE waves
since this corresponds to the longest available fetch, with
other directional sectors being limited in occurrence and
energetic content, due to the coast orientation and the
presence of the Balearic Islands.
In the particular case of the Ebro region, eastern wave
storms tend to occur simultaneously with surged water
levels, related to the passage of low-pressure systems off
the delta (Sa
´nchez-Arcilla and Jime
´nez 1994; Jime
et al. 1997). In this case, the most important effects are
related to the inundation of agricultural zones plus the
affectation of natural values due to wave exposure and
flooding. All these effects result in a large ‘‘impulsive’
coastal erosion (see Fig. 4for a sample illustration).
Sea surface temperature
The oceans have a large capacity for storing and redis-
tributing heat. By storing heat, they delay global tempera-
ture increases, but this goes together with an increase in
evaporation and, thus, precipitation. Overall ocean tem-
peratures show a rising trend consistent with the observed
increase in air temperatures (Levitius et al. 2000). The
western Mediterranean and North Atlantic react in a
manner similar to that of global oceans. In the 1990s, these
seas warmed by about 0.5°C (Rixen et al. 2005; Vargas-
˜ez et al. 2009).
More specifically, the annual mean, maximum and
minimum values of sea surface temperature (SST) show a
clear increasing trend (Fig. 8a). However, the intra-annual
viability is so pronounced that it tends to mask this longer
term trend, which is about 0.77°C/decade in the Ebro sta-
tion (Fig. 8b). The increasing trend of SST is linked to a
similar behaviour in air temperature evolution (Fig. 9a
for the Catalan Coast). This pattern is also observed
(Fig. 9b–d) for the rest of coastal sites. In particular, the
duration of storms (hrs.)
Mean Duration of Storms
Sens Slope Hs=1.5
Sens Slope Hs=2.0
1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 200 6
number of storms
Number of Storms
Linear Trend Hs=1.5
Linear Trend Hs=2.0
Fig. 5 Mean duration of moderate (above an Hs threshold of 1.5 m)
and severe (above an Hs threshold of 2.0 m) storms (left) and number
of occurrences (right) for the same two storm types. Both panels
correspond to the observed wave data series off the Ebro Delta, in the
Spanish NW Mediterranean coast
Climatic drivers of potential hazards in Mediterranean coasts 625
`s mean-maximum temperature data from 1950 to
2005 (provided by the Tunisia National Meteorological
Centre) show a 0.29°C/decade increase with a clear
acceleration during the last 30 years. This means that,
although no instrumental records are available, there
should be a general SST increase in all coastal stations.
Among the extreme natural events that struck the Earth
and our coastal societies in recent times, some of the most
violent (e.g. hurricane Charley (category 4 on the Saffir-
Simpson scale, in August 2004), Ivan (category 3, in
September 2004), Katrina (category 4, August 2005), etc.)
have been related to this increase in sea surface temperatures
(SST). Several studies suggest that global warming will
likely result in SST increase, which will enhance the inten-
sity of extreme storms (Sun et al. 2007) and mean sea levels.
This also applies regionally, where the largest, ever recor-
ded, significant wave height in the Catalan coast occurred in
the Costa Brava region—near the border between Spain and
France—in December 2008. Therefore, it is a matter of when
rather than if such extreme natural events will occur.
Wave Height (m)
Swell Gabès
Swell Site2 34º00.5'N 10º20.0E
Swell Site2 Linear Trend
1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 19 84 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994
1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005
Wave Height (m)
Ebro Delta
Swell Ebro Hs Max Hipocas
Swell Ebro Hs Max Linear Trend
Fig. 6 Yearly mean hind-cast
Hs values for the Gabe
and Catalan (bottom) coasts.
The data have been provided by
the Ministe
`re de l’Equipement
et l’Habitat for Tunisia and by
Puertos del Estado, Ministry of
Public Works for Spain (see
626 A. Sa
´nchez-Arcilla et al.
General framework
In this section, we present the implications of climatic
variability on erosion and water quality [both bio-geo-
physical hazards (Adger 2006)], driven by changes in
physical parameters. The assessment should be in terms of
the average trend and the estimated changes in variance.
However, in order to be consistent with the paucity of
available data, we shall only perform the exercise for the
medium trend.
Even with this simplified approach, there remain a large
number of uncertainties. They can be classified in seven
large blocks, of which the first four are the normally
accepted sources of uncertainty in climatic scenarios
(Somot et al. 2006,2008; Terray and Braconnot 2007).
They can be summarized as follows:
Green house gas emissions, related to the socioeco-
nomic behaviour and technological developments.
Modelling performance, related to the employed equa-
tions and parameterizations.
Type of downscaling (physical or statistical) and selected
boundary conditions, plus the considered feedbacks.
The inherent limits of predictability, which vary
depending on the nonlinearity of the sub-system prop-
erty considered (for instance, about 1 year for features
such as the North Atlantic oscillation or the ENSO).
It is also important to include three additional sources of
uncertainty, which may become even dominant in terms of
the resulting hazards. They are related to:
The response function that links climatic drivers to the
desired ‘‘property’’ of the coastal system and that is
normally poorly known. For instance, computations of
sediment transport rates may present errors of up to
100% (see e.g. Ca
´ceres et al. 2009).
The threshold needed to calculate hazards, which is
also an open question mark for many practical appli-
cations related to erosion, flooding or water quality.
Fig. 7 Directional wave distribution along the Spanish Coast. The
radial axis indicates frequencies of occurrence. aLlobregat wave
buoy that corresponds to the Barcelona coast, bCap Tortosa buoy that
corresponds to the Ebro Delta cost and cCullera Bay that corresponds
to the central/south Valencia Gulf (sources:Sa
´nchez-Arcilla et al.
2008a a,band Mo
¨sso et al. 2007 c)
1970 1975 1980 1985 1990 1995 2000 2005 2010
Temperature ºC
Estartit Yearly Averaged Mean, Min and Max Temp.
Yearly Averaged Mean Temperature
Yearly Averaged Max Temperature
Yearly Averaged Min Temperature
Fig. 8 a Annual mean (middle curve), maximum (upper curve) and
minimum (lower curve) sea surface temperature (SST) at the Northern
Catalan Coast (Estartit station), for the period 1969–2008 (left) and
bmonthly SST in front of the Ebro Delta, for the period 1990–2008
(right). Data sources: SMC (Servei Meteorologic de Catalunya) and
Josep Pascual
Climatic drivers of potential hazards in Mediterranean coasts 627
The probability distribution functions of drivers and
responses which is seldom known and is introduced in
terms of a mean, or, at most a mean plus a standard
deviation. This presents particular problems, especially
for extremes since the tail of the distributions are
sensitive to all previous hypotheses.
Such a wide fan of uncertainties also applies to the four
studied field sites, which are characteristic examples of
Northern and Southern Mediterranean coasts (Fig. 1). They
have been analysed covering a wide range of physical
drivers with some Esocioeconomic implications. Uncer-
tainties begin with the fact that the Mediterranean is a
particularly vulnerable region to climate changes (Gouba-
nova and Li 2007) and has shown large climatic shifts in
the past, being identified as one of the most prominent
‘hot-spots’’ in future climatic change projections (Giorgi
2006). Given that the Mediterranean is a transition area
between the temperate climate of central Europe and the
arid climate of northern Africa, changes have the potential
to deeply modify the climatic characteristics of the
Mediterranean. The population density plus these effects
could result in devastating impacts on water resources,
natural ecosystems (both terrestrial and marine), human
activities (e.g. agriculture, recreation, tourism) and health
(Giorgi and Lionello 2008).
Flooding is the most common of these environmental
hazards, and the number of people vulnerable to it is
increasing as populations rise and the alternative settlement
sites decrease. In particular, floods are the most common
kind of natural hazard in the Western Mediterranean region
(Milelli et al. 2006), either in river basins by intense
rainfalls over small catchments (flash floods) or by ener-
getic sea storm events, acting on low-lying coastal areas.
Because of this torrential character of the climate,
droughts are one of the main climatic hazards affecting
Mediterranean regions. In Spain, they have become a fre-
quent phenomenon due to the high spatial and temporal
variability of precipitation. They are controlled by atmo-
spheric circulation patterns in the North Atlantic (Barri-
endos and Llasat 2003; Vicente-Serrano and Cuadrat 2007)
Temperature ºC
Ebro Delta
Air Temperature
Running average
Deviation ºC
Gulf of Oran
Deviation ºC
Polynomial Fit
Deviation ºC
Summer Daily MaximumTemperature
Linear Trend
SUM 0.36 0.55 0.75 ºC/decade
1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 1925 1930 1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010
1970 1975 1980 1985 1990 1995 2000 2005 2010 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010
Deviation ºC
West Nile Delta
Deviation Annual Mean Temperature
Polynomial Fit
(a) (b)
(c) (d)
Fig. 9 Air temperature evolution at aCatalan Coast, bGulf of Oran,
cGulf of Gabe
`s and dWest Nile Delta. In all four cases, disregarding
the type of statistical analyses or whether they refer to absolute
temperature data or temperature deviation, there is an increasing trend
over the observation period
628 A. Sa
´nchez-Arcilla et al.
and also by local cyclo-genesis. Drought periods can result
in significant loses for crop yields (Quiring and Papa-
kryiakou 2003), increasing the risk of forest fires (Pausas
2004), gradual reduction in tree growth (Ko
¨rner et al. 2005)
and triggering processes of land degradation and deserti-
fication (Schlesinger et al. 1990).
Sea temperatures control atmosphere–ocean exchanges
and are, thus, linked to evaporation and precipitation rates.
The associated hazards come, mainly, from coastal flood-
ing due to continental run-off. Water temperature also
controls the solubility of certain substances—among them
dissolved oxygen—and primary production (Manasrah
et al. 2006; Markfort and Hondzo 2009). This results in a
factor affecting water quality, as described below.
Water temperature regulates ecosystem functioning both
directly, through physiological effects on organisms, and
indirectly, as a consequence of habitat loss. Photosynthesis
and aerobic respiration and the growth, reproduction,
metabolism and mobility of organisms are all affected by
changes in water temperature. Indeed, the rates of bio-
chemical reactions usually double when temperature is
increased by 10°C within the given tolerance interval of an
organism, and this also applies to microbial processes such
as nitrogen fixation, nitrification and denitrification.
Aquatic organisms can only survive within a particular
temperature range. If temperature goes too far above or
below (positive or negative temperature anomalies of only
a few degrees can induce mortality), the tolerance for a
given species (e.g. fish, insects, benthic invertebrates,
zooplankton, phytoplankton & microbes) and its ability to
survive may be compromised. Unnatural changes in water
temperature impact indirectly upon biota through loss of
supporting habitat, by changing the solubility of oxygen
and calcium carbonate (calcite or aragonite) in water or by
influencing the extent to which metal contaminants and
other toxicants are assimilated by physiological processes.
Water temperature is also, probably, the most important
factor influencing viral persistence in estuarine environ-
ments, since it affects the density, conductivity and pH of
the water column.
In addition, the solubility of gases (e.g. dissolved oxy-
gen and carbon dioxide) decreases with increasing tem-
perature (solubility being the maximum amount of gas that
can be dissolved in a given volume of water). Water is
more likely to become anoxic or hypoxic under warmer
conditions, because of increased bacterial respiration and a
decreased ability of water to hold dissolved oxygen.
If SST warming continues, the solubility of CO
thus the net uptake of it by the oceans will decrease. On the
other hand, ocean warming can activate zoo- and phyto-
plankton, the so-called ‘‘biological pump’’, which is
responsible for the oceans’ biological uptake of CO
However, the decreasing physical solubility of CO
warmer seas could override the positive effect of the bio-
logical pump, in terms of global average and also for
regional scales, such as in the case of the Mediterranean
(Westby et al. 2002).
Physical hazards based on sediment balance:
forcing terms
Within the framework just presented, there is a variety of
physical hazards that can be considered. We shall focus on
erosion and water quality at climatic scales. Coastal ero-
sion will be addressed in terms of the corresponding sedi-
ment balance, whose main drivers are analysed in what
The first obvious climatic driver is sea-level rise which,
as mentioned in previous sections, has experienced during
the twentieth century in the Mediterranean an average rise
of about 10 cm. By 2100, all SRES scenarios (Nakicenovic
et al. 2000) predict an average rise of 18–59 cm. No better
estimation is presently available for the Mediterranean, far
less distinguishing between the Eastern and Western sides
or Northern vs. Southern shores. Based on the available
time series, the short-term rates of SLR for the four studied
sites, excluding subsidence, are found to be smaller than
5 mm per year for Spain (Catalan Coast), Oran and Gabe
and between 5 and 10 mm per year for the Nile Delta.
More specifically, there appears to be a relatively steady
sea level in the Spanish case (less than 1 mm per year of
change), while mean sea level appears to be increasing in
the southern shore (e.g. Gabe
`s) since 1992, at a rate of
about 2 mm per year.
The subsidence rates have been taken as close to 0 for
`s and Oran, as 2.5 mm per year for sinking areas in
the Catalan coast such as the Ebro Delta and of about 4 mm
per year for the Nile Delta. These values correspond to the
last decades, being representative of some ‘‘contemporary’
interval in the last century. They are in agreement with the
present state-of-art (Emery et al. 1988;Sa
et al. 1998; Somoza et al. 1998; Ericson et al. 2006) but
should be considered as the best possible educated guess at
this time, due to the lack of more solid geophysical evi-
dence. However, they are considered to be suitable for the
vulnerability analysis to be performed in next section.
A more accurate estimation is, however, urgently
required in the near future, since even small increases or
variations in these parameters can produce a large impact.
As an example, 1 cm of sea-level rise increases the flooded
area by various metres in the low-lying areas along the
Mediterranean coast, and a sea-level rise of 1 m has been
estimated to produce a loss of 10% of the available
emerged plain in the Nile Delta (Dasgupta et al. 2007).
This justifies the need for an enhanced monitoring effort in
the coming future.
Climatic drivers of potential hazards in Mediterranean coasts 629
These same limitations apply to other climatic vari-
ables such as river discharge or wave storminess. In the
case of river discharge, there should be a distinction
between liquid and solid transport, and this latter variable
should be split into bed, suspended and wash loads.
Bed-load transport, which is mostly sand, has been
significantly reduced in all regulated rivers (see e.g.
´nchez-Arcilla et al. 1996). However, wash-load and
suspended fluxes are not so sharply reduced, although
they only provide fine material such as silt or clay, which
is not suitable for building a stable shoreline. The same
fate applies to nutrient discharges, important for the bio-
logical productivity of the coastal sea, which is also
dependent on the liquid discharge. In the case of regulated
rivers, the experience from Northern Mediterranean
shores of the European Union (e.g. the Deltas of the Ebro,
Rhone or Po) is that river regulation exerts a stronger
control than climatic variability (Sa
´nchez-Arcilla et al.
1996; Sierra et al. 2004).
Physical hazards: erosion
We shall now estimate coastal erosion due to relative sea-
level rise, without considering any further reductions in
river sedimentary supplies with respect to the present sit-
uation, because of the stronger effects of river regulation
when compared to climate variability. The corresponding
erosion rates appear in Table 2. In this table, the ‘‘recent
past’’ corresponds to the last century, while the ‘‘present’
estimates have been obtained assuming a 1 mm sea-level
rise per year as an average figure for the whole domain.
The ‘‘near future’’ rates correspond to the interval
2050–2100 and have been obtained assuming an increase
in sea level by 2100 of about 50 cm. The displayed figures
correspond to an average estimate, assuming a ‘‘solid’
response of the shoreline to sea-level rise based on a
simplified version on Bruun’s rule. However, it should be
explicitly stated that the actual response will vary from
beach to beach, depending on sediment and profile features
and the availability of space for the required beach erosion.
Because of that these numbers, expressed in horizontal
metres of erosion, should be considered as rough estimates
to illustrate the variability across Mediterranean coasts.
The numbers can nevertheless be used to perform a
regional scale analysis.
Regarding storm events, there appears to be a slight
increase in the number of moderate storms during the fall
period, based, as it was described in previous sections, on
the thunderstorms for the Oran Gulf and on the wave
storms for the Catalan region. However, the number of
more energetic events appears to be decreasing, while there
is an increase in storm duration (based on a limited set of
data from the Catalan case).
The beach profile erosion associated to wave storms
depends on both intensity and duration (see e.g. Sa
Arcilla et al. 2008b). If, as justified in previous sections, we
assume an increase in duration of 2 h per decade, then we
can estimate the corresponding increase in eroded volume
as approximately 2 m
/m (for the extra 2 storm hours)
based on the previous reference. This results in an erosion
increase of 2 m per decade, using a berm height of between
1.0 and 2.0 m, since we are including also part of the
submerged beach profile to calculate the balance. This
would result in 20 m of extra erosion by 2100 for the
Catalan, Nile and Oran cases, while the Gabe
`s case, more
sheltered, has not been considered to be subject to this
effect. The increase in number of storms reported from the
Oran case has been considered to be included in the 2 h per
decade increase in duration (in terms of resulting erosion)
since these 2 h per decade may come from either a longer
duration or an increase in the number of storms.
Adding this enhanced erosion due to wave storminess to
the previously calculated figures, resulting from relative
sea-level rise, we end up with the estimates presented in
Table 3, which again correspond to the horizontal average
erosion expected for 2100.
The combined erosion for the year 2100 is, therefore,
around 70 m for the most favourable cases of the Spanish
NW Mediterranean Coast (excluding deltas) and Gabe
Gulf, while it goes up to 95 m or even 110 m for subsiding
areas (Nile and Ebro Deltas) or the Oran case. This illus-
trates the high vulnerability of many of the beaches located
in our four sites which, for the urban beaches, seldom have
widths in excess of 100 m.
It is also possible to estimate the ‘‘coping capability’’ of
a given beach, based on the minimum beach width needed
to perform the protection function associated to a given
sandy stretch (Valdemoro et al. 2007). Defining that the
minimum reserve width for protection should be similar to
the erosion produced by two consecutive storms (Bolan
et al. 2007), we can estimate the storm induced erosion as
Table 2 Shoreline erosion rates in horizontal metres, due to SLR for
the last century (recent past), present conditions (present) and by the
year 2100 (near future)
Site Recent past Present Near future
No sub Sub No Sub Sub No sub Sub
Valencia 0 10 50
Ebro Delta 25 35 75
Oran 25 35 75
`s25 35 75
Nile 40 50 90
A distinction is made between the sites without subsidence (no sub)
and those with subsidence (sub). The uncertainty in the estimates
should be always considered
630 A. Sa
´nchez-Arcilla et al.
30 m
/m (Sa
´nchez-Arcilla et al. 2008b). This results in
erosion, approximately, 30 m of horizontal retreat, using
again a berm height between 1 and 2 metres and consi-
dering also part of the active submerged beach profile.
The effect of these 2 consecutive storms would, there-
fore, require a width of about 60 m, which would be the
minimum sub-aerial beach required to cope with present
meteo-oceanographic conditions. For the corresponding
climatic-scale assessment, it is necessary to add the margin
due to the worsening of climatic conditions, which are
shown in Tables 2and 3. The end result of all that is that
an average width of 150 metres should be prescribed
throughout Mediterranean coasts to ensure the survival for
many of our beaches.
Physicochemical hazards: water quality
Looking now at coastal water quality, we can relate it to
climate dynamics in terms of precipitation and dissolved
oxygen in the water column. Precipitation affects water
quality, in the sense that it determines the concentration of
pollutants coming from river discharges or from the dis-
tributed continental run-off. If we assume that concentra-
tion is inversely proportional to the discharged volume and,
therefore, for a constant drainage area, inversely propor-
tional to the precipitation rate, this results in water quality
being directly proportional to precipitation rate (assuming
that the amount of pollutants remains constant). Intuitively,
this simply means that higher precipitation rates produce a
higher dilution and therefore should improve water quality.
Of course this is a crude simplifying hypothesis, since
impulsive rain events (at least the first of a series) would
have to ‘‘cleanse’’ the drainage system and, thus, contribute
a higher concentration of pollutants. However, the extra
momentum of torrential discharges favour river plumes
that are able to cross the continental shelf (Sa
and Simpson 2002) and, thus, reduce the local pollutant
load. All things considered, we have opted for a robust,
simple analysis to achieve some regional order of magni-
tude estimates as presented below.
Yearly average precipitation has experienced a reduc-
tion from about 400 mm in the interval 1927–1997 to
around 300 mm in the interval 1978–2007 (for the Oran
case). This supposes a decrease in precipitation, and thus
water quality, of about 20%. Future scenarios, although
less robust for precipitation than for variables such as
temperature, predict a reduction in precipitation of about
5% for the Northern Mediterranean Coast and of about
20–25% for the Southern Mediterranean Coast (rounded
estimates after Christensen et al. 2007). This corresponds
to A1B scenarios, where the rapid economic growth goes
accompanied by more efficient technologies.
Based on these numbers and the work performed within
the CIRCE project, we are assuming that, under present
conditions, the precipitation in the Spanish case has
remained reasonable steady, while there has been an
increase in the Gabe
`s case in winter and a decrease in the
Oran case starting in 1970 (this includes the 30-year severe
drought experienced by Oran from 1977 to 2007). The Nile
case has shown a decrease in precipitation in the 1970 and
1980 s and a further decrease in the 1990 and 2000s. The
associated changes in water quality (expressed as per-
centages) for the four studied cases appear in Table 4.
These numbers should be considered as representative
of the trend, since they constitute a rough estimate of the
variation in water quality due to precipitation changes.
They also fail to consider the local scale differences in
climatic variability. Moreover, the distinction between
summer and winter periods should be also handled with
care since it represents the forecast variation in precipita-
tion, depending on the season within the year. Regarding
water quality, we should also consider that the expected
change towards more pulsed river discharges, linked to
more torrential precipitations concentrated in time, should
also increase the amount of pollutants discharged to the
coastal sea. This effect is nearly impossible to assess with
the present level of information and has not, therefore, been
included in the analysis.
Table 3 Shoreline erosion rates in horizontal metres due to
SLR ?storm effects for the last century (recent past), present con-
ditions (present) and by the year 2100 (near future)
Site Recent past Present Near future
No sub Sub No sub Sub No sub Sub
Valencia 0 10 70
Ebro Delta 25 35 95
Oran 25 35 95
Nile 40 50 110
A distinction is made between the sites without subsidence (no sub)
and those with subsidence (sub)
The uncertainty in the estimates should be always considered
Table 4 Water quality percentual variations driven by precipitation
Present (%) Near future
Average (%) Summer (%) Winter (%)
Oran -20 -40 -50 -40
Spanish coast 0 -5-30 0
`s0-20 -25 -20
Nile 0 -20 -5-20
Present conditions are indicated by ‘‘present’’, while the estimates for
the year 2100 appear as ‘‘near future’
The uncertainty in the estimates should be always considered
Climatic drivers of potential hazards in Mediterranean coasts 631
Water quality can also be assessed from the amount of
dissolved oxygen (DO) in a water ‘‘parcel’’. The DO will
change within the water column and as a function of the
spatial hydrodynamic pattern. It will also depend on the
water temperature and several other physicochemical
parameters. In this work, we have considered only the
relation to water temperature to infer the impact of future
climatic scenarios.
Based on previous campaigns and analyses, we have
found out that the DO range in the Mediterranean is
roughly between 5 and 12 mg/l. Below 5 mg/l, the aquatic
system becomes stressed and the WQ degrades sharply
(Benson and Krause 1984; Boyd 2000). Assuming a linear
relation of DO with temperature, it is obtained that DO
decreases by about 2% (0.15 mg/l) for each Celsius degree
of temperature increase. In terms of water quality, con-
sidering that we would need about 15°C of temperature
increase to reach the 5 mg/l threshold, this means a WQ
decrease of about 7% for each Celsius degree of temper-
ature increase. This means that we would need an increase
in temperature of 5°for the dissolved oxygen to get below
the 5 mg per litre for deep water and an increase of 17°for
dissolved oxygen to go below this threshold for surface
Water quality is, therefore, inversely related to the
temperature via the level of dissolved oxygen. This means
that the sea surface temperature (SST) range included in
climatic projections can be translated into percentual
decreases in water quality via the dissolved oxygen rate
proposed above. This relationship amounts to about a 7%
decrease per Celsius degree. If we apply that to the pro-
jected scenarios, we end up with the numbers presented in
Table 5.
The obtained variations in water quality correspond to
the forecast changes in air and water temperatures in the
Mediterranean, which are higher than the world average
(Somot et al. 2008). These numbers have been obtained
based on the A2 scenario. The expected increase in the
warm period or summer season, estimated in about 10 days
per decade for the Gabe
`s case, should also lead to a dete-
rioration of the corresponding water quality since the water
volume and the contained aquatic ecosystem would be
exposed to the forecast increases for a longer period of
The performed analyses illustrate the possible range of
effects of climatic variability in a given coastal region.
These effects will be linked to socioeconomic impacts
originated by an increase in mean sea level, storminess
and/or water/air temperatures. We have seen how these
increases vary for the four studied sites and the uncer-
tainties in the quantifications. The resulting erosion,
flooding, water quality degradation and salinization will
require, as schematized in Fig. 10, further energy
consumption and they are, thus, likely to enhance human-
induced climatic change.
From the presented analysis, it is concluded that the more
direct and robust climatic indicators for the state of coastal
zones are mean sea level and wave storminess for erosion
and flooding and water temperature and precipitation for
water quality. Erosion due to increases in relative mean-
sea-level appears due to the incident waves being able to
reach higher parts of the Coastal Winter-land, normally not
expressed directly to wave action without that rise in sea
level. Erosion also appears due to enhanced wave storms
due to offshorewards directed transport and, in general, a
reshaping of the shore to get in equilibrium with the new
wave conditions. Erosion is, thus, related to (1) relative
level between land and sea, (2) energy of storms and (3)
other storm features such as duration, wave steepness (ratio
of wave height to wave length), wave orientation with a
respect to the coast and repetition of energetic events (i.e.
frequency of occurrence).
Water quality on the other hand is related to (1) water
temperature and (2) precipitation features such as volume,
duration and repetition or frequency of occurrence.
Increased precipitation favours dilution, and this leads to
improved water quality, although the amount of discharged
pollutants may also become larger. The raise in water
temperature decrease the amount of dissolved oxygen in
the water and should, therefore, lead to a worsening of
ecosystem conditions, which may reach anoxia for certain
semi-enclosed bodies of water such as the Mediterranean
lagoons found in our study sites.
Table 5 Percentual variation in water quality driven by temperature
changes for present conditions and by the year 2100 (denoted as near
Present rates Near future
Spanish Coast ?3.3°C?5.0°C
-20% -40%
Oran Gulf ?4°C?2°C?6°C
-30% -10% -50%
`s Gulf ?4°C?2°C?6°C
-30% -10% -50%
Nile Coast ?4°C?2°C?6°C
-30% -10% -50%
Winter Summer
Present Near future
Values of average variation in SST (sea surface temperature) and WQ
(water quality) are shown simultaneously (SST/WQ) for the present
conditions and the accelerated rate due to climate change. The
uncertainty in the estimates should be always considered
632 A. Sa
´nchez-Arcilla et al.
Sea surface temperature appears to be increasing in all
studied sites, with a clear upward trend for the annual
mean. This should lead to lower values of dissolved oxygen
which, together with the decrease in average precipitation
plus a concentration into more torrential events, will result
in water quality degradation.
Although the available level of instrumental information
and the errors in simulated fields preclude any final con-
clusion, there are a number of commonalities and differ-
ences to be observed. Precipitation interannual variability
is so large that it hampers deriving any common pattern for
all studied sites. There appears, however, to be a slight
increasing trend in the number of moderate storms. This
could support the incipient evidence towards a higher
number of impulsive events (wave storms, precipitation,
etc.) in the area. The resulting impact, for a squeezed coast
such as the Mediterranean, subject to storms from more
than one direction, would be enhanced erosion and flood-
ing. The human response should, accordingly, be an
‘ordered’’ retreat from the immediate coastline, in what is
nowadays called managed realignment. Alternatively, for
selected stretches of the coast where this realignment is not
possible (e.g. coastal cities), there should be a reenforce-
ment of defence structures, including if at all possible a
wide enough beach (natural or, more likely, artificial) in
front. The human response should, thus, be a careful design
of sea-outfalls, avoiding semi-enclosed bodies of water and
periods of abnormally high temperature and/or low water
renovation. This implies managing coastal waters using the
available knowledge on oceanographic variables and the
corresponding wave and current operational predictions.
This information could also be used to achieve safer
bathing water conditions, regulating access and preferential
areas as a function of the prevailing meteo-oceanographic
The associated impacts will be cross-sectorial and with
feedbacks at multiple scales, some of which may, in turn,
require higher energy consumption and an enhancement of
climatic change. This illustrates the importance to act in an
anticipatory manner, invoking in case of doubt the
Fig. 10 Schematization of the
conceptual relation between
climate hazards and cross-
sectorial socioeconomic
impacts, for the coastal cases
studied in this paper
Climatic drivers of potential hazards in Mediterranean coasts 633
precautionary principle, so that we can preserve an envi-
ronment as valuable and unique as the Mediterranean
coastal fringe.
Acknowledgments This work has been funded by the EU project
CIRCE (ref. TST5-CT-2007-036961) and the research project ARCO
(ref. 200800050084350) from the Spanish Ministry of Environment.
The authors also went to acknowledge the use of data from various
public organizations in the four studied sites, as described in the text,
with a special mention to Mr. Josep Pascual.
Adger WN (2006) Vulnerability. Glob Environ Change 16:68–281
Barriendos M, Llasat MC (2003) The case of the ‘Malda
´’ anomaly in
the western Mediterranean basin (AD 1760–1800): an example
of strong climatic variability. Clim Change 61:191–216
Bates BC, Kundzwwicz ZW, Wu S, Palutikov JP (eds) (2008)
Climate change and water. Technical paper of the Intergovern-
mental Panel on Climate Change. IPCC Secretariat, Geneva,
p 210
Bel Hassen M, Drira Z, Hamza A, Ayadi H, Akrout F, Messaoudi S,
Issaoui H, Aleya L, Bouaı
¨n A (2009) Phytoplankton dynamics
related to water mass properties in the Gulf of Gabes: ecological
implications. J Mar Syst 75:216–226
Benson BB, Krause D (1984) The concentration and isotopic
fractionation of oxygen dissolved in freshwater and seawater
in equilibrium with the atmosphere. Limnol Oceanogr
´ranger K, Mortier L, Gasparini GP, Gervasio L, Astraldi M,
Crepon M (2004) The dynamics of the Sycili Strait: a
comprehensive study from observations and models. Deep Sea
Res 51:411–440
˜os R, Sa
´nchez-Arcilla A, Go
´mez J, Cateura J (2004) Limits of
operational prediction in the north-western Mediterranean. In:
Proceedings of 29th international conference on coastal engi-
neering, Lisbon, Portugal, pp 818–829
˜os R, Sa
´nchez-Arcilla A, Cateura J (2007) Evaluation of two
atmospheric models for wind-wave modelling in the NW
Mediterranean. J Mar Syst 65:336–353
Boyd CE (2000) Water quality. An introduction. Kluwer Academic
Publishers, pp 330
Brunet M, Sigro
´J, Jones PD, Saladie
´O, Aguilar E, Moberg A, Lister
D, Walther A (2007) Long-term changes in extreme tempera-
tures and precipitation in Spain. Contrib Sci 3:331–342
´ceres I, Alsina JM, Sa
´nchez-Arcilla A (2009) Mobile bed
experiments focused to study the swash zone evolution.
J Coast Res SI56:1736–1740
Calafat FM, Gomis D (2009) Reconstruction of Mediterranean sea
level fields for the period 1945–2000. Glob Planet Change
Cavaleri L, Bertotti L (2006) The improvement of modelled wind and
wave fields with increasing resolution. Ocean Eng 33:553–565
Changnon SD (2003) Measures of economic impacts of weather
extremes. Bull Am Meteorol Soc 84:1231–1235
Chegaar M, Chibani A (2001) Global solar radiation estimation in
Algeria. Energy Convers Manag 42:967–973
Chen CC, McCarl BA, Schimmelpfenning DE (2004) Yield variabil-
ity as influenced by climate: a statistical investigation. Clim
Change 66:239–261
Christensen JH, Hewitson B, Busuioc A, Chen A, Gao X, Held I,
Jones R, Kolli RK, Kwon W-T, Laprise R, Magan
˜a Rueda V,
Mearns L, Mene
´ndez CG, Ra
¨nen J, Rinke A, Sarr A, Whetton
P (2007) Regional climate projections. In: Solomon S, Qin D,
Manning M, Chen Z, Marquis M, Averyt KB, Tignor M, Miller
HL (eds) Climate change 2007: the physical science basis
Contribution of working group I to the fourth assessment report
of the intergovernmental panel on climate change. Cambridge
University Press, Cambridge
Cooper MJP, Beevers MD, Oppenheimer M (2008) The potential
impacts of sea level rise on the coastal region of New Jersey,
USA. Clim Change 90:475–492
Dasgupta S, Laplante B, Meisner C, Wheeler D, Yan J (2007) The
impact of sea-level rise on developing countries: a comparative
analysis. World Bank policy research paper 4136, Washington,
Drira Z, Hamza A, Belhassen M, Ayadi H, Bouaı
¨n A, Aleya L (2008)
Dynamics of dinoflagellates and environmental factors during
the summer in the Gulf of Gabes (Tunisia, Eastern Mediterra-
nean Sea). Sci Mar 72:59–71
Emery KO, Aubrey DG, Goldsmith V (1988) Coastal neotectonics
of the Mediterranean from tide-gauge records. Mar Geol
Ericson JP, Vo
¨smarty CJ, Dingman SL, Ward LG, Meybeck M
(2006) Effective sea-level rise and deltas: causes of change and
human dimension implications. Glob Planet Change 50:63–82
Garcia MA, Sa
´nchez-Arcilla A, Sierra JP, Sospedra J, Go
´mez J
(1993) Wind waves off the Ebro Delta, NW Mediterranean.
J Mar Syst 4:235–262
Gibelin AL, De
´M (2003) Anthropogenic climate change over the
Mediterranean region simulated by a global variable resolution
model. Clim Dyn 20:327–339
Giorgi F (2006) Climatic change hot-spots. Geophys Res Lett
Giorgi F, Lionello P (2008) Climate change projections for the
Mediterranean region. Glob Planet Change 63:90–104
Giorgi F, Bi X, Pal JS (2004) Mean, interannual variability and trends
in a regional climate change experiment over Europe. II: climate
change scenarios (2071–2100). Clim Dyn 23:839–858
Gomis D, Ruiz S, Sotillo MG, A
´lvarez-Fanjul E, Terradas J (2008)
Low frequency Mediterranean Sea level variability: the contri-
bution of atmospheric pressure and wind. Glob Planet Change
Goubanova K, Li L (2007) Extremes in temperature and precipitation
around the Mediterranean basin in an ensemble of future climate
scenario simulations. Glob Planet Change 57:27–42
Hamilton JM, Tol RSJ (2007) The impact of climate change on
tourism in Germany, the UK and Ireland: a simulation study.
Reg Environ Change 7:161–172
Hill J, Stellmes M, Udelhoven T, Ro
¨der A, Sommer S (2008)
Mediterranean desertification and land degradation. Mapping
related land use change syndromes based on satellite observa-
tions. Glob Planet Change 64:146–157
˜ez C, Prat N, Canicio A (1996) Changes in the hydrology and
sediment transport produced by large dams on the lower Ebro
River and its estuary. Regul River Res Manage 12:51–62
Iglesias A, Rosenzweig C, Pereira D (2000) Agricultural impacts of
climate change in Spain: developing tools for a spatial analysis.
Glob Environ Change 10:69–80
IPCC, 2001: Climate Change 2001: The Scientific Basis. Contribution
of Working Group I to the Third Assessment Report of the
Intergovernmental Panel on Climate Change, J.T. Houghton, Y.
Ding, D.J. Griggs, M. Noguer, P.J. van der Linden, X. Dai, K.
Maskell and C.A. Johnson, Eds., Cambridge University Press,
Cambridge, UK, 881pp
Ismail-Zadeh A, Takeuchi K (2007) Preventive disaster management
of extreme natural events. Nat Hazards 42:459–467
´nez J (2005) Effects of storm impacts in the Ebro Delta coast.
Floodsite report T26-10-10, pp 31
634 A. Sa
´nchez-Arcilla et al.
´nez J, Sanchez-Arcilla A, Valdemoro H, Gracia V, Nieto F
(1997) Processes reshaping the Ebro Delta. Mar Geol 144:59–79
Kharim VV, Zwiers FW (2000) Changes in extremes in an ensemble
of transient climate simulations with a coupled atmosphere–
ocean GCM. J Clim 13:3760–3788
¨rner C, Sarris D, Christodoulakis D (2005) Long-term increase in
climatic dryness in the East-Mediterranean as evidenced for the
island of Samos. Reg Environ Change 5:27–36
Kurian NP, Nirupama N, Baba M, Thomas KV (2009) Coastal
flooding due to synoptic scale, meso-scale and remote forcings.
Nat Hazards 48:259–273
Levitius S, Antonov JI, Boyer TP, Stephens C (2000) Warming of the
world ocean. Science 287:2225–2229
Liebsch G, Novotny K, Dietrich R (2002) Untersuchung von
Pegelreihen zur Bestimmung der A
¨nderung des mittleren
Meeresspiegels an den europa
¨ischen Ku
¨sten. Technische
¨t Dresden (TUD), Germany
Lionello P, Dalan F, Elvini E (2002) Cyclones in the Mediterranean
region: the present and the doubled CO
climate scenarios. Clim
Res 22:147–159
Lionello P, Boldrin U, Giorgi F (2008a) Future changes in cyclone
climatology over Europe as inferred from a regional climate
simulation. Clim Dyn 30:657–671
Lionello P, Cogo S, Galati MB, Sanna A (2008b) The Mediterranean
surface wave climatic inferred from future scenario simulations.
Glob Planet Change 63:152–162
Mahmoudi H, Spahis N, Goosen MF, Sablani S, Abdul-wahab SA,
Ghaffour N, Drouiche N (2009) Assessment of wind energy to
power solar brackish water greenhouse desalination units: a case
study from Algeria. Renew Sustain Energy Rev 13:2149–2155
Manasrah R, Rasheed M, Badran M (2006) Relationships between
water temperature, nutrients and dissolved oxygen in the
northern Gulf of Aqaba, Red Sea. Oceanologia 48:237–253
Maracchi G, Sirotenko O, Bindi M (2005) Impacts of present and
future climate variability on agriculture and forestry in the
temperate regions: Europe. Clim Change 70:117–135
˜o MG (1992) Implications of climatic change on the Ebro Delta.
In: Jeftic L, Milliman JD, Sestini G (eds) Climate change and the
Mediterranean. Edward Arnold, London, pp 304–327
Markfort CD, Hondzo M (2009) Dissolved oxygen measurements in
aquatic environments: the effects of changing temperature and
pressureon three sensortechnologies. JEnviron Qual 38:1766–1774
Merzouk NK (2000) Wind energy potential of Algeria. Renew Energy
Metzeger MJ, Schro
¨ter D (2006) Towards a spatially explicit and
quantitative vulnerability assessment of environmental change in
Europe. Reg Environ Change 6:201–216
Milelli M, Llasat MC, Ducrocq V (2006) The cases of June 2000,
November 2002 and September 2002 as examples of Mediter-
ranean floods. Nat Hazards Earth Syst Sci 6:271–284
Millot C (1987) The circulation of the Levantine Intermediate Water
in the Algerian basin. J Geophys Res 92:8265–8276
Millot C, Benzhora M, Taupier-Letage I (1997) Circulation in the
Algerian basin inferred from the MEDIPROD-5 current-meter
data. Deep Sea Res 44:1467–1495
Moreno AR (2006) Climate change and human health in Latin
America: drivers, effects and policies. Reg Environ Change
Morhange C, Pirazzoli PA (2005) Mid-holocene emergence of
southern Tunisian coasts. Mar Geol 220:205–213
¨sso C, Sierra JP, Mestres M, Cupul L, Falco S, Rodilla M,
´nchez-Arcilla A, Gonza
´lez del Rı
´o J (2007) The influence of
topography on wind-induced hydrodynamics in Cullera bay.
J Coast Res SI 47:17–30
Nakicenovic N, Davidson O, Davis G, Gru
¨bler A, Kram T, Lebre La
Rovere E, Metz B, Morita T, Pepper W, Pitcher H, Sankovski A,
Shukla P, Swart R, Watson R, Dadi Z (2000) Special report on
emissions scenarios: a special report of working group III of the
intergovernmental panel on climate change. Cambridge Univer-
sity Press, Cambridge, p 599
Nicholls RJ, Hoozemaans FMJ (1996) The Mediterranean: vulnera-
bility to coastal implications of climate change. Ocean Coast
Manage 31:105–132
Nicholls N, Gruza GV, Jouzel J, Karl TR, Ogallo LA, Parker DE
(1996) Observed climate variability and change. In: Houghton
JT, Meiro Filho LG, Callendar BA, Kattenburg A, Maskell K
(eds) Climate change 1995. The science of climate change, vol
572. Cambridge University Press, Cambridge, pp 133–192
Olesen JE, Carter TR, Diaz-Ambrona CH, Fonzek S, Heideman T,
Hickler T, Holt T, Minguez MI, Morales P, Palutikov JP, Quemada
M, Ruiz-Ramos M, Rubaek GH, Sau F, Smith B, Sykes MT (2007)
Uncertainties in projected impacts of climate change on European
agriculture and terrestrial ecosystems based on scenarios from
regional climate models. Clim Change 81:123–143
Oueslati A (1992) Salt marshes in the Gulf of Gabes (Southeastern
Tunisia): their morphology and recent dynamics. J Coast Res
Parry ML, Rosenzweig C, Iglesias A, Livermore M, Fischer G (2004)
Effects of climate change on global food production under SRES
emissions and socio-economic scenarios. Glob Environ Change
Pausas JG (2004) Changes in fire and climate in the eastern Iberian
Peninsula (Mediterranean basin). Clim Change 63:337–350
´JL, Arı
´stegui J, Cana L, Gonza
´vila M (2005) Coupling
between the open ocean and the coastal upwelling region off
northwest Africa: water recirculation and offshore pumping of
organic matter. J Mar Syst 54:3–37
´rez-Domingo S, Castellanos C, Junoy J (2008) The sandy beach
macrofauna of Gulf of Gabe
`s (Tunisia). Mar Ecol Evol Perspect
Poulain PM, Zambianchi E (2007) Near-surface circulation in the
central Mediterranean Sea as deduced from Lagrangian drifters
in the 1990s. Cont Shelf Res 27:981–1001
Quiring SM, Papakryiakou TN (2003) An evaluation of agricultural
drought indices for the Canadian prairies. Agric Forest Meteorol
Raper SCB, Wigley TML, Warrick RA (2001) Global sea-level rise:
past and future. In: Milliman JD, Hag BU (eds) Sea level rise and
coastal subsidence: causes, consequences and strategies. Springer
Ratsimandresy AW, Sotillo MG, Carretero Albiach JC, A
Fanjul E, Hajji H (2008) A 44-year high-resolution ocean and
atmospheric hindcast for the Mediterranean Basin developed
within the HIPOCAS Project. Coast Eng 55:827–842
Reidsma P, Ewert F, Lansink AO, Leemans R (2009) Vulnerabilty
and adaptation of European farmers: a multi-level analysis of
yield and income responses to climate variability. Reg Environ
Change 9:25–40
Rixen M, Bakers J-M, Levitius S, Antonov J, Boyer T, Maillard C,
Fichaut M, Balopoulos E, Iona S, Dooley H, Garcı
´a MJ, Manca
B, Giorgetti A, Mazella G, Mikhailov N, Pinardi N, Zavatarelli
M (2005) The Western Mediterranean deep water: a proxy for
climate change. Geophys Res Lett 32:L12608
´az JA, Weatherhead EK, Knox JW, Camacho E (2007)
Climate change impacts on irrigation water requirements in the
Guadalquivir river basin in Spain. Reg Environ Change
Rowell DP (2005) A scenario of European climate change for the late
twenty-first century: seasonal means and interannual variability.
Clim Dyn 25:837–849
Saarikko RA (2000) Applying a site based crop model to estimate
regional yields under current and changed climates. Ecol Model
Climatic drivers of potential hazards in Mediterranean coasts 635
Sammari C, Koutitonsky VG, Moussa M (2006) Sea level variability
and tidal resonance in the Gulf of Gabes, Tunisia. Cont Shelf Res
´nchez E, Gallardo C, Gaertner MA, Arribas A, Castro M (2004)
Future climate extreme events in the Mediterranean simulated by
a regional climate model: a first approach. Glob Planet Change
´nchez-Arcilla A, Jime
´nez JA (1994) Breaching in a wave-
dominated barrier spit: the Trabucador Bar (Northeastern
Spanish Coast). Earth Surf Proc Land 19:483–498
´nchez-Arcilla A, Jime
´nez JA (1997) Physical impacts of climatic
change on deltaic coastal systems (I): an approach. Clim Change
´nchez-Arcilla A, Simpson JH (2002) The narrow shelf concept:
coupling and fluxes. Cont Shelf Res 22:153–172
´nchez-Arcilla A, Jime
´nez JA, Stive MJF, Iban
˜ez C, Prat N, Day
JW, Capobianco M (1996) Impacts of sea-level rise on the Ebro
Delta: a first approach. Ocean Coast Manage 30:197–216
´nchez-Arcilla A, Jime
´nez JA, Valdemoro HI (1998) The Ebro
Delta: morphodynamics and vulnerability. J Coast Res
´nchez-Arcilla A, Gonza
´lez-Marco D, Mo
¨sso C, Go
´mez J (2005)
Morphodynamic control on extreme coastal drivers. In: Pro-
ceedings of 5th international conference on coastal dynamics’05,
Barcelona, Spain
´nchez-Arcilla A, Mo
¨sso C, Mestres M, Cupul L, Sierra JP, Rodilla
M, Romero I, Gonza
´lez del Rı
´o J (2007) Hydrodynamics of a
coastal bay nature and man-made barriers. J Coast Res
´nchez-Arcilla A, Gonza
´lez-Marco D, Bolan
˜os R (2008a) A review
of wave climate prediction along the Spanish Mediterranean
coast. Nat Hazards Earth Syst Sci 8:1217–1228
´nchez-Arcilla A, Mendoza ET, Jime
´nez JA, Pen
˜a C, Galofre
Novoa M (2008b) Beach erosion and storm parameters. Uncer-
tainties for the Spanish Mediterranean. In: Proceedings of 31st
international conference on coastal engineering, Hamburg,
Germany, pp 2352–2362
Schlesinger WH, Reynolds JF, Cunningham GL, Huenneke LF,
Jarrell WM, Virginia RA, Whitford WG (1990) Biological
feedbacks in global desertification. Science 247:1043–1048
Sierra JP, Sa
´nchez-Arcilla A, Gonza
´lez del Rı
´o J, Flos J, Movella
¨sso C, Martı
´nez R, Rodilla M, Falco S, Romero I (2002)
Spatial distribution of nutrients in the Ebro estuary and plume.
Cont Shelf Res 22:361–378
Sierra JP, Sa
´nchez-Arcilla A, Figueras PA, Gonza
´lez del Rı
Rassmussen EK, Mo
¨sso C (2004) Effects of discharge reductions
on salt wedge dynamics of the Ebro River. River Res Appl
Somot S, Sevault F, De
´M (2006) Transient climate change
scenario simulation of the Mediterranean Sea for the 21st
century using a high-resolution ocean circulation model. Clim
Dyn 27:851–879
Somot S, Sevault F, De
´M, Cre
´pon M (2008) Twenty-first century
climate change scenario for the Mediterranean using a coupled
Atmosphere-Ocean Regional Climate Model. Glob Planet
Change 63:112–126
Somoza L, Barnolas A, Arasa A, Maestro A, Rees J, Herna
Molina FJ (1998) Architectural stacking patterns of the Ebro
Delta controlled by Holocene high-frequency eustatic fluctua-
tions, delta-lobe switching and subsidence processes. Sediment
Geol 117:11–32
Stanley DJ (1988) Subsidence in the northeastern Nile delta: rapid
rates, possible causes and consequences. Science 240:497–500
Stanley DJ (1989) Sediment transport on the coast and shelf between
the Nile delta and Israeli margin as determined by heavy
minerals. J Coast Res 5:813–828
Stanley DJ (1990) Recent subsidence and northeast tilting of the Nile
delta, Egypt. Mar Geol 94:147–154
Stanley DJ, Goodfriend GA (1997) Recent subsidence of the northern
Suez Canal. Nature 388:335–336
Stanley DJ, Warne AG (1998) Nile delta in its destruction phase.
J Coast Res 14:794–825
Stanley DJ, Nir Y, Galili E (1998) Clay mineral distribution to
interpret Nile cell provenance and dispersal: III. Offshore margin
between Nile delta and northern Israel. J Coast Res 14:196–217
Sun D, Kafatos M, Cervone G, Boybeyi Z, Yang R (2007) Satellite
microwave detected SST anomalies and hurricane intensifica-
tion. Nat Hazards 43:273–284
Terray L, Braconnot P (2007) Livre Blanc ESCRIME. E
´tude des
´narios Climatiques Re
´s par l’IPSL et Me
´o IPSL and Me
´o-France, pp 70
Torriani D, Calanca P, Lips M, Ammann H, Beniston M, Fuhrer J
(2007) Regional assessment of climate change impacts on maize
productivity and associated production risk in Switzerland. Reg
Environ Change 7:209–221
Trnka M, Dubrovsky M, Zalud Z (2004) Climate change impacts and
adaptation strategies in spring barley production in the Czech
Republic. Clim Change 64:227–255
Turki S, Harzallah A, Sammari C (2006) Ocurrence of harmful
dinoflagellates in two different Tunisian ecosystems: the lake of
Bizerte and the gulf of Gabes. Cah Biol Mar 47:253–260
Valdemoro HI, Sanchez-Arcilla A, Jimenez JA (2007) Coastal
dynamics and wetlands stability. The Ebro Delta case. Hydro-
biologia 577:17–29
˜ez M, Moya F, Tel E, Garcı
´nez MC, Guerber E,
Bourgeon M (2009) Warming and salting in the western
Mediterranean during the second half of the twentieth century:
inconsistencies unknowns and the effect of data processing. Sci
Mar 73:7–28
Vicente-Serrano SM (2007) Evaluating the impact of drought using
remote sensing in a Mediterranean, semi-arid region. Nat
Hazards 40:173–208
Vicente-Serrano SM, Cuadrat JM (2007) North Atlantic control of
droughts in North-East Spain: evaluation since 1600 AD. Clim
Change 85:357–379
Voss R, May W, Roeckner E (2002) Enhanced resolution modeling
study on anthropogenic climate change: changes in extremes of
the hydrological cycle. Int J Climatol 22:755–777
Westby A, Owens JD, Sparringa RA, Kendall M (2002) Effects of
temperature, pH, water activity and CO
concentration on
growth of Rhizopus oligosporus NRRL 2710. J Appl Microbiol
636 A. Sa
´nchez-Arcilla et al.
... Coastal areas are very exposed to hazards like erosion and flooding (Arnoux et al., 2021;Gallien, 2016;Kron, 2013;Xie et al., 2019). Risks associated to these hazards are expected to increase in the next years due to sea level rise (SLR) and extreme events related to waves and storm surge (Casas-Prat et al., 2016;Grases et al., 2020;Izaguirre et al., 2011;Kirshen et al., 2008;Lin et al., 2016;Neumann et al., 201 ;Nicholls et al., 2011;Sánchez-Arcilla et al., 2011;oodruff et al., 2013). ...
Full-text available
New flume experiments with surrogate seagrass meadows are presented. The experiments included the creation of a full-scale and realistic Posidonia Oceanica model to evaluate the effect over wave attenuation, sediment transport and shoreline erosion. A hydrodynamic and morphodynamic comparison between cases with seagrass and without seagrass for two wave energy conditions was performed. Meadow density and submergence ratio were constant for tests under irregular waves. The wave height reduction, bar crest location, total sediment transport and shoreline position were used to evaluate the coastal protection efficiency of the meadow. The measured wave heights suffered a reduction due to the presence of the seagrass. These reductions were persistent in the area located between the onshore edge of the meadow and the depth of closure, being of greater magnitude in the more energetic case. All tests showed the development of a bar and the migration of the crest offshore over time. However, the dissipation of the incoming wave energy on the meadow made the bar crest stay closer to the shoreline and consequently generated a lower freeboard. In addition, the bar migration rate was reduced by the simulated meadow effect, in particular in the lower energetic case. A sediment volume significantly smaller was transported offshore when the seagrass meadow was present in both wave conditions. Additionally, in the higher energy case, a smaller shoreline retreat was observed when the meadow was present.
... Coastal areas in some countries particularly in the global south are highly susceptible to the various impacts of climate change due to anthropogenic and natural climatic factors (Bouwer 2011;DasGupta and Shaw 2013;Nath and Behera 2011;Sivakumar and Stefanski 2010). Severe changes in climatic and weather conditions, rapid sea-level rise (SLR), storm surge, temperature fluctuations and irregular rainfall trends have increased coastal vulnerability problems in the majority of coastal regions across the globe, resulting in huge losses of coastlines, properties and damage to coastal communities (Burkett 2012; Gupta et al. 2019;Lal 2003;Mimura 2013;Sánchez-Arcilla et al. 2011). Likewise, many coastal states of India suffer severe cyclonic storms leading to flooding. ...
Full-text available
Indian coastal regions have often been affected by frequent climate-induced natural disasters such as cyclones, floods, droughts and other related hazards in recent decades. Existing literature was not sufficient to fully understand these event trends from diverse perspectives in a systematised manner at current scenarios. Therefore, a systematic approach has been employed to assess the climate change and cyclone trends of nine Indian coastal states by using various geographical information system (GIS) tools for 2006-2020. The results showed that 61 cyclones occurred in nine coastal states from 2006 to 2020; the highest numbers were recorded in Odisha (20), West Bengal (14) and Andhra Pradesh (11). Accordingly, these three coastal states emerged as the most vulnerable for high-intensity cyclones. The results also identified that the highest average temperature (29.3 °C) was recorded at Tamil Nadu and Gujarat, and the lowest temperature (26.7 °C) was recorded in West Bengal and Odisha. Most of the coastal states showed fluctuations in temperatures during the study period. At the same time, Kerala and Karnataka states recorded the highest average rainfall (2341 mm and 2261 mm) and highest relative humidity (78.11% and 76.57%). Conversely, the Gujarat and West Bengal states recorded the lowest relative humidity at 59.65% and 70.78%. Based on these results, the current study generated GIS vulnerability maps for climate change and cyclone activity, allowing one to rank each state's vulnerability. Cumulatively, these results and maps assist in understanding the driving mechanisms of climate change, cyclones and will contribute towards more effective and efficient sustainable disaster management in the future.
... The three main variables of CC (elevated CO 2 , altered rainfall patterns, and temperature ranges) aggravate seawater rise; drought, heatwaves, wildfires, storms, and floods [118]. Increasing the global temperatures by 0.798 °C and concentration of CO 2 level from 280 to 379 ppm equivalent on pre-industrial levels would have an impact on timing seasons of flora, and fauna [119]. ...
Full-text available
Climate change is happening due to natural factors and human activities. It expressively alters biodiversity, agricultural production, and food security. Mainly, narrowly adapted and endemic species are under extinction. Accordingly, concerns over species extinction are warranted as it provides food for all life forms and primary health care for more than 60–80% of humans globally. Nevertheless, the impact of climate change on biodiversity and food security has been recognized, little is explored compared to the magnitude of the problem globally. Therefore, the objectives of this review are to identify, appraise, and synthesize the link between climate change, biodiversity, and food security. Data, climatic models, emission, migration, and extinction scenarios, and outputs from previous publications were used. Due to climate change, distributions of species have shifted to higher elevations at a median rate of 11.0 m and 16.9 km per decade to higher latitudes. Accordingly, extinction rates of 1103 species under migration scenarios, provide 21–23% with unlimited migration and 38–52% with no migration. When an environmental variation occurs on a timescale shorter than the life of the plant any response could be in terms of a plastic phenotype. However, phenotypic plasticity could buffer species against the long-term effects of climate change. Furthermore, climate change affects food security particularly in communities and locations that depend on rain-fed agriculture. Crops and plants have thresholds beyond which growth and yield are compromised. Accordingly, agricultural yields in Africa alone could be decline by more than 30% in 2050. Therefore, solving food shortages through bringing extra land into agriculture and exploiting new fish stocks is a costly solution, when protecting biodiversity is given priority. Therefore, mitigating food waste, compensating food-insecure people conserving biodiversity, effective use of genetic resources, and traditional ecological knowledge could decrease further biodiversity loss, and meet food security under climate change scenarios. However, achieving food security under such scenario requires strong policies, releasing high-yielding stress resistant varieties, developing climate resilient irrigation structures, and agriculture. Therefore, degraded land restoration, land use changes, use of bio-energy, sustainable forest management, and community based biodiversity conservation are recommended to mitigate climate change impacts.
... Three out of these profiles were studied in each of the study sites, corresponding to the maximum, namely 17.1% for Area 1, 16.2% for Area 2, and 14.5% for Area 3, and the minimum slopes, namely 1.2% for Area 1, 5.7% for Area 2, and 3.0% for Area 3. Slopes close to the median (i.e., 7.5% for Area 1, 11.6% for Area 2, and 8.5% for Area 3) were also selected. Only modelled H s corresponding to incoming waves that propagate on directions affecting the three study areas and exceeding a threshold of 1.5 m for durations more than six hours [26,[66][67][68][69][70], were initially selected at an offshore representative point of the SWAN model grid in each of the three study areas. The H s data covering the entire 1951-2100 period, also coupled with the associated T p , have been first corrected for bias [15]. ...
Full-text available
In the present work, a methodological framework, based on nonstationary extreme value analysis of nearshore sea-state parameters, is proposed for the identification of climate change impacts on coastal zone and port defense structures. The applications refer to the estimation of coastal hazards on characteristic Mediterranean microtidal littoral zones and the calculation of failure probabilities of typical rubble mound breakwaters in Greek ports. The proposed methodology hinges on the extraction of extreme wave characteristics and sea levels due to storm events affecting the coast, a nonstationary extreme value analysis of sea-state parameters and coastal responses using moving time windows, a fitting of parametric trends to nonstationary parameter estimates of the extreme value models, and an assessment of nonstationary failure probabilities on engineered port protection. The analysis includes estimation of extreme total water level (TWL) on several Greek coasts to approximate the projected coastal flooding hazard under climate change conditions in the 21st century. The TWL calculation considers the wave characteristics, sea level height due to storm surges, mean sea level (MSL) rise, and astronomical tidal ranges of the study areas. Moreover, the failure probabilities of a typical coastal defense structure are assessed for several failure mechanisms, considering variations in MSL, extreme wave climates, and storm surges in the vicinity of ports, within the framework of reliability analysis based on the nonstationary generalized extreme value (GEV) distribution. The methodology supports the investigation of future safety levels and possible periods of increased vulnerability of the studied structure to different ultimate limit states under extreme marine weather conditions associated with climate change, aiming at the development of appropriate upgrading solutions. The analysis suggests that the assumption of stationarity might underestimate the total failure probability of coastal structures under future extreme marine conditions.
... Simulations of global climate models suggest that annual average rainfall amounts may increase, but the turnaround time for heavy rainfall events may in the meanwhile decrease (Lionello et al. 2002). This shift in the patterns of rainfall may lead to increased flooding during the rainy season, particularly in low-lying coastal areas (Sánchez-Arcilla et al. 2011). Hence, the investigation of the changes and trends of rainfall patterns was the subject of much research in different region worldwide. ...
Rainfall and air temperature are significant parameters to establish the climatic condition of a region and their patterns of variations are, nowadays, key elements to judge the issue of climate change. The present study affords an analysis of long-term rainfall and air temperature records to establish their trends of variations in Alexandria and to, therefore, conclude the presence or absence of climate change in this important City. The data set of the two parameters extended on monthly basis over 40 years from 1980 to 2019. The analyses and the trends of the two parameters were carried out by the MS Excel® 2010, reflecting increasing trends with rates of 2.94 mm/year and 0.04 °C/year in rainfall and air temperature, respectively. Results also revealed a positive relationship (+0.21) between mean annual rainfall and air temperature, while the mean monthly records of the two parameters reflected a negative relationship of − 0.72. From the trends investigation, it is expected that Alexandria will examine an increase in the number of rainy days in April, May and September. The mean annual rainfall anomaly was +19.38 mm an indication of an increasing rainfall trend while the mean annual air temperature anomaly for the study period was +0.3 °C showing that the mean annual temperatures are rising in the study area. Therefore, this increasing mean annual rainfall accompanied with rising mean temperatures is considered indicator of the presence of climate change that can be experienced in Alexandria.
... The influence of the astronomical tide and the meteorological tide (atmospheric pressure and sea elevations caused by the wind and the waves) can produce variations of about one meter [36]. The significant wave height (Hs) is 0.75 m, the mean wave period (Tm) is 3.9 s [23], and the storm waves can be exceeding 2 m [37]. The eastern wave component, the higher and more energetic waves, is the predominant cause of morphological changes [6]. ...
Full-text available
The aim of this work is to apply a vulnerability index in the dune field located in the Riumar urban zone at the mouth of the Ebro River. This dune field represents the natural barrier of the El Garxal coastal lagoon system. The index used integrates the dimensions of exposure, suscep-tibility, and resilience from the analysis of 19 variables. The results obtained show moderate susceptibility and high resilience, which are in line with the behavior of this dune field during the last sea storms (Gloria in January 2020 and Philomena in January 2021, among others) that have tested the capacity of this system to cope with the effects of these storms. Therefore, in-creasing the knowledge of the factors affecting the vulnerability of the dunes can be helpful in the management and conservation of these coastal environments.
Biotic life below water entails life in oceans, seas, rivers, estuaries, lakes, and other bodies that store water and this biotic life below water comprises organisms, both big and small, ranging from large fish, mammals, reptiles, and other tiny species. The marine life is threatened by both environmental and anthropogenic stressors. Ocean warming, acidification, deoxygenation, sea-level rise are the major components of environmental stressors; and anthropogenic stressors include plastic pollution, oil-spills, overfishing, greenhouse gases, etc. Besides, there are land-based pollution sources. In order to sustain life below water, ecosystem-based management (EBM) is suggested to overcome environmental and anthropogenic stressors.
The rising intensity and recurrence of wave storm events can seriously impact navigation and coastal and offshore structures in the Western Mediterranean Sea. Therefore, the present study is focused on wave storm events in the Western Mediterranean Sea, over the last four decades. The spatial decadal variations of wave storm events are shown, considering variations in the parameters that characterise wave storms, such as significant wave height (SWH), wave storm duration, and wave storm direction. Additionally, the decadal variation in wave storm intensities is evaluated through the storm power index (SPI) and the total storm wave energy (TSWE). The study is based on a wave hindcast, developed using a calibrated SWAN model. The wave storm events are obtained based on the SWH time series for 24 325 locations, distributed over an unstructured grid, covering the entire Western Mediterranean Sea. The decadal variation in the number of wave storm events, maximum and mean wave storm duration, SPI, and TSWE were observed in large parts of the West Mediterranean Sea during the last four decades. However, variations in mean SWH during these storms are low, and do not show a real implication in the decadal changes in the wave storm intensity (SPI and TSWE). Locations of significant increasing changes in SPI and TSWE show a dependence on changes in the wave storm duration. They may be related to variations in wave storm direction in some areas. Increases in wave storm duration are mainly responsible for increases in wave storm intensities over the last decade.
This paper intends to assess the potential impacts of the future SLR on the operability of berthing structures and to estimate in monetary terms the adaptation costs to it. To do this, three scenarios of SLR are considered, two corresponding to the last assessment report of IPCC (RCP4.5 and RCP8.5) and the other being a high-end scenario (HES), with a low probability of occurrence but physically possible. The research is focused on the case study of Tangier-Med port, which is considered as an economic magnet for the northern region of Morocco and the centerpiece of the government strategy for port development. The results show that the operability of the port will be affected only under the HES and from 2090 onwards. However, by 2100, in this scenario all the docks would be affected, especially the service terminal and those dedicated to containers, hydrocarbons, vehicles and general cargo, in which the percentage of inoperability could exceed 30% of the time. This would lead to traffic losses of 1.9 million TEUS and more than 22 million tons of cargo by 2100 while the adaptation costs would exceed 40 million euros (in present monetary units).
One of the most used measures to counteract coastal erosion is beach nourishment. It has advantages with respect to the use of rigid structures that sometimes entail non desired impacts on the surrounding areas. However, beach nourishments are often unsuccessful, requiring frequent refills due to the use of sediments that are not suitable. In this paper, a methodological framework for increasing the probability of success of beach nourishment projects is presented. First, this framework consists of detecting potential borrowing areas, by analysing shoreline evolution and selecting the stretch that shows a more accretive character. Once the borrowing area has been identified, several sand extraction options are defined. The beach response (in terms of erosion and flooding) to each sand extraction alternative is analysed by using two numerical models, which simulate the hydro-morphodynamic patterns in the studied area. The numerical model results allow to find the best extraction alternative, which is that producing the least impact in the borrow area. As an example, the methodology is applied to a stretch of the Catalan coast (NW Mediterranean) to illustrate its potential. The proposed methodology shows to be a useful tool for helping coastal managers to optimize their available resources.
This paper reviews research traditions of vulnerability to environmental change and the challenges for present vulnerability research in integrating with the domains of resilience and adaptation. Vulnerability is the state of susceptibility to harm from exposure to stresses associated with environmental and social change and from the absence of capacity to adapt. Antecedent traditions include theories of vulnerability as entitlement failure and theories of hazard. Each of these areas has contributed to present formulations of vulnerability to environmental change as a characteristic of social-ecological systems linked to resilience. Research on vulnerability to the impacts of climate change spans all the antecedent and successor traditions. The challenges for vulnerability research are to develop robust and credible measures, to incorporate diverse methods that include perceptions of risk and vulnerability, and to incorporate governance research on the mechanisms that mediate vulnerability and promote adaptive action and resilience. These challenges are common to the domains of vulnerability, adaptation and resilience and form common ground for consilience and integration.
The Ebro Delta, located on the coast of north-east Spain has a population of about 19 000. Primary economic activities in the Delta are agriculture and fisheries. The natural values of the Delta are also of great importance as the low-lying parts and the lagoons represent essential nesting and resting areas for large numbers of migratory aquatic birds. The principal consequences of the predicted climatic change and sea-level rise will be the aggravation of human-induced erosion and reshaping of the Delta coastline, affecting the wetlands and the natural areas which may eventually disappear. Although subsidence is not an important factor today, it may become so in the future if water management is not planned wisely and water extraction from the aquifers increases significantly. Little consequence is expected over the short term with respect to economic activities or infrastructures in urbanized areas, as the tourist development of the Delta is moderate and the main infrastructures are located inland. The main land-based activities that could be impacted are the aquaculture plants in the Alfaques Bay and the salt-production facilities in the Alfaques Peninsula. The possible change in the nutrients cycle due to the reshaping of the bays may also affect the productivity of the adjacent sea and reduce the fisheries in the area. The Ebro Delta is a good example of the pre-eminent role played by human activities in the problems attributed to the climatic change. It is clear that the main problems will arise from human-induced modifications; climatic change will only aggravate them. -from Author
Five years (1998, 2000-2003) of summer records of temperature, nutrients and dissolved oxygen concentrations in the upper 400 m of the water column of the northern Gulf of Aqaba were employed to produce a simple statistical model of the relationship between temperature versus nitrate, phosphate, silicate and dissolved oxygen concentrations. Temperature profiles in the upper 400 m during summer revealed a clear thermocline in the upper 200 m. This was reflected in nutrient and oxygen concentrations as nitrate, phosphate, and silicate increased from the surface to deep water while dissolved oxygen decreased. The best fit relationship between temperature versus nitrate and phosphate was inverse linear and the best fit correlation between temperature versus silicate and dissolved oxygen was fractional. The observed nutrient concentrations were shaped by a combination of the hydrodynamics and biological factors. Deep winter mixing and high nutrient concentrations dominate during winter. Shortly after the water stratifies in spring, the nutrients are drawn down by phytoplankton during the spring bloom and remain low throughout the rest of the year. The regression equations presented here will be useful in estimating nutrient concentrations from temperature records as long as the annual natural cycle is the main driver of nutrient concentrations and external inputs are insignificant. Deviations from these relationships in the future could provide insight into modifications in the nutrient concentrations probably resulting from new nutrient sources, such as anthropogenic inputs.
The revised second edition updates and expands the discussion, and incorporates additional figures and illustrative problems. Improvements include a new chapter on basic chemistry, a more comprehensive chapter on hydrology, and an updated chapter on regulations and standards. This book presents the basic aspects of water quality, emphasizing physical, chemical, and biological factors. The study of water quality draws information from a variety of disciplines including chemistry, biology, mathematics, physics, engineering, and resource management. University training in water quality is often limited to specialized courses in engineering, ecology, and fisheries curricula. This book also offers a basic understanding of water quality to professionals who are not formally trained in the subject. Because it employs only first-year college-level chemistry and very basic physics, the book is well-suited as the foundation for a general introductory course in water quality. It is equally useful as a guide for self-study and an in-depth resource for general readers.
Data points summarized in the present study are largely from samples collected prior to 1964 and thus provide a pre-Aswan High Dam baseline. Recommended systematic resampling of the margins and analyses of heavy minerals one quarter-Century after closure of the High Aswan Dam would help measure recent sedimentation changes and predict future modifications likely to affect these margins. -from Author
This paper reviews observationally based estimates of past global-mean temperature change and sea-level rise and compares them with model-based estimates. The climate model used is a simple upwelling-diffusion, energy-balance model, which is coupled to a set of simple ice-melt models to give total sea-level change. For best-guess model parameter values there is reasonable agreement between observed and modelled results. The same models are used to estimate future temperature changes and sea-level rise for the standard IPCC95 set of emissions scenarios, updating earlier work. Projected warming over 1990–2100 ranges between 1.4 and 2.9°C for the central emissions scenario (1595a), while sea-level rise ranges between 20 and 86 cm. Mid-value estimates for a climate sensitivity of 2.5°C for a CO2 doubling are 2.0°C and 49 cm. Temperature and sea-level rise estimates are also given (out to 2500) for five standard (IPCC) CO2 concentration scenarios in which CO2 levels stabilize at 350, 450, 550, 650 and 750 ppmv. The sea-level-rise commitment after stabilization is very large: for stabilization levels of 550 ppmv or above, sea-level rise continues for many centuries at rates similar to those occurring at the stabilization point in spite of the constancy of radiative forcing. Finally, the sensitivity of these results to changes in the ocean’s thermohaline circulation is examined. The effects of a thermohaline slowdown are reduced warming rate and increased rate of sea-level rise.