Given at
Open Meeting Of The Global Environmental
Change Research Community Rio De Janeiro
6-8 October, 2001
Carlos Rodríguez Otero, Ada Pérez Hernández, Isidro Salas García
CUBA, 2001
Global Chance and Vulnerability of the Coastal Zone in Cuba
Introducción
Our objectives are study the risk and vulnerability in the coastal zones elements by the global change
and variability, among them concentrated and insolated population, forests and crops areas, and other
economic activities.
With the propose measures of adaptation that constitute an important tool for the territorial
classification and management of the coastal zones in the different levels of physical planning,
national, provincial, municipal and urban for short, medium and long time.
Cuba is the largest island in the Caribbean Sea, its coastline is of 6 000 kilometers length, excluding
the numerous keys surrounding it. The coastal line is predominantly low-lying and accumulative. The
total estimate population is 11 217 000 inhabitants of and nearly 13 % of it lives in coastal zones of the
island, without including the population of Havana city.
Coastal zone environments in the Caribbean Sea represents an important natural resource for
population and tourism. It is an ecosystem with high level of biodiversity, extremely fragile, and
therefore vulnerable to human interventions.
In the Cuban case its coastal zones are vulnerable to:
-
The climate variability -by extreme meteorological events, generate long periods of drought and
frequent floods
- The climate change, meanly due to sea- level rise with direct and indirect effects
- The human activities
Main effects are land use changes, loss of soils, mangroves, coral reefs and marine grasses, beach
erosion, retreated shoreline in low and marshy areas, contamination and soil and water salinization
(figure 1).
Fig.1 Natural and anthropics impacts on coastal ecosystems
Coastal zone definition
Coastal zone is the area of contact between land and sea, is scarce, vulnerable and dynamic territory,
where natural, economic, demographic, social and environmental aspects come together, their width is
varies and depends the coastal characteristic and research objective.
In our assessment of vulnerability of coastal zone we found two well defined regions (figure 2), a first
one up to 1000 meters length inland, the most which vulnerable territories with a greater impact due to
a sea- level rise by the increasing frequency and intensity of severe meteorological events.
A second region of medium and low impact goes from 1000 to 12000 meters inland, generally
matching with 5 meters high, upper limit of the coastal floods. Whole area of vulnerability matches
with areas where a salinization process of soil and underground waters is present.
Fig.2 Coastal zone delimitation
Scenarios the climate variability and change for Cuba (CO2 duplication)
The scenario of variability and climate change for Cuba is:
- An increment of temperature for the year 2100 will be 1.6 - 2.5 0 C
- Changes on precipitation rate of 10 - 15 %
- Similar activity of tropical cyclones as nowadays
- An increasing numbers of cold fronts due to ENSO events
- Equal number of southern winds
- Increase of drought periods mainly in the eastern region
The average sea- level rise in Cuba during the last three decades is 2.9 mm/year. Projecting it with
high sensibility to the year 2100 it will be 95 centimeters (table 1). Considering the difficulties with
the available cartographic, the affectations have been computed for 1 meter of altitude.
Table 1. Projection sea level rise in Cuba
Year
2050
2100
Sensibility
low
high
8 cm
44 cm
20 cm
95 cm
Source: Centella et al., 1999
A numeric dynamic model was developed for foresee of hurricane storm surges on Cuba’s insular
shelve and coastlines. The recurrent periods of storm surges in 26 sectors of the Cuban coasts are
calculated with the informative base over 100 years, including frequency of surges and physical
factors (figure 3), the most dangerous coastal sectors are marked in red.
.
Figure 3. Map storm surge
Source: Salas, et al., 2001
The table 2 show an example the storm surges in selected sectors. The numerical dynamic model
calculated the height and recurrent periods of surges for current and perspective times, for this last one
with the scenario of 1 meter sea- level rise, the surges behavior will increase only 4%, in both cases
the values and similar.
Table 2. Storm Surges in sectors 9, 10, 11 and 12
Recurrent Periods
(cases/year)
1/100
1/50
1/20
1/10
Source: Salas, et al., 2001
Storm Surges High (m)
Forecasted
Actual
Scenario 1 m.
3,7
3,8
2,2
2,3
0,7
0,9
0,5
0,7
The risk map by surges from tropical cyclones (figure 4) allows to observe a differentiation of 26
coastal sectors, with four qualitative categories of intensity and frequency.
The most dangerous coastal sector is located in the south coast of Havana province with 143 km length.
It presents the highest values of sea- level rise periodic from storm surges and by the awaited climate
change. Each year have take place floods surpassing one meter high and 5 km more than once
inland, situation that motivates the occurrence of the population's frequent evacuations.
Fig. 4 Risk map by tropical cyclones surge for coastal sectors of Cuba
Source: Salas et al., 1997
Settlement and coastal population
The Human Settlements System in Cuba is well structured and studied. There are 11 217 000
inhabitants, the rate of growth is 3.3 thousand inhabitants per year and the density of the population is
99.2 inh/ km2. projections of the population indicate that its growth tends to decrease mainly due to the
descent of fecundity.
In the future, a certain stability of the current of Human Settlements System will be prevalent. The
economy will be based on a moderated industrialization, on the development of tourism and on the
creation of free zones. This will not generate processes of quick urbanization and it will depend
mainly on the existent settlements. The stabilization of the system will be decisive in the arrangement
of territory as a way of mitigating the impact produced by the climate change.
The historical behavior of the Cuban population evidences a tendency to concentrate on searching
better life conditions and maximizing the use of agricultural soils. The quick process of urbanization
reaches 75,2% in the year 2000. The internal migratory processes occurs step by step. First, the
isolated population concentrates in rural settlement with no less than 200 inhabitants, later on it will
migrate towards urban settlements. In Cuba, this process of migration does not result in demographic
explosion.
The country has more than 6800 settlements, 573 of them are classified as urban, the rest are rural,
and 1 million inhabitants live in disperse form.
There are 245 coastal settlements in ranging from 0 to 1000 meters from shoreline, without Havana
city, concentrating a population of 1.4 million inhabitants, that live in more than a quarter of a million
dwellings, for an index of 4 inhabitants /housing _similar to the national rate. 84% of these settlements
containing more than 97% of the coastal population are located in the first 200 m from the coastal
line. There are 62 classified as urban and 182 as rural, only about three thousand persons live in
disperse form. A prevalence of settlements in accumulative low coasts is observed, followed by mixed
and abrasive coasts (Pérez and Rodríguez, 1998).
U r b a n 6 2 , 1 1 % o f t o t a l,
1 , 3 M M in h a b it a n t s ,
3 3 0 0 0 0 d w e llin g s , 1 2 c it ie s
c ic it
244
s e t t le m e n t s
R u ra l 1 8 2 , 0 ,0 3 % o f to ta l
5 2 0 0 0 in h a b it a n t s , 1 8 0 0 0 d w e llin g s ,
7 9 s e t t le m e n t s w it h m o r e t h a n 2 0 0 in h a b .
D is p e r s e p o p u la t io n , 0 , 0 0 3 % o f t o t a l,
2 9 7 4 in h a b it a n t s
P o p u la t io n
Fig. 5 Coastal Settlements
Source: Pérez et al., 1997
1 9 9 2 1 4 1 0 5 0 4 in h a b it a n t s
1 9 9 5 1 4 6 4 0 5 4 in h a b it a n t s
The dynamics of the concentrated coastal population evidences that the urban settlements consolidate
its role in the territory, in spite of the economic existent difficulties, due to the industrial and touristic
development. In some settlements affected by frequent coastal floods, some policies for reducing the
concentration of population are applied. The rural settlements begin to decrease, being more
significant the case of those with less than 200 inhabitants, which show rates of negative growth
below national average for this level of Human Settlements System, which is - 1.10%.
The figure 6 shown the coastal settlements distribution in the country, there are more coastal
settlements in the eastern region of the island, most of them are rural with less than 200 located on
abrasive coasts.
There are 98 coastal settlements most vulnerable coastal settlements to sea- level rise located totally or
partially in the height range between 0 and 1 m, which represents more than 50 000 inhabitants living
in 17 000 dwellings, 42 of them are urban and 56 rural (figure 7).
Figure 7 Coastal settlements located totally or partially between 0 and 1 meter
Source: Pérez et al., 1997
Nowadays, 52 settlements with a total population of 656 155 inhabitants have reported coastal floods
due to storm surge caused by tropical hurricanes or the intensification and frecuence of the
extratropical cyclones in the Gulf of Mexico. In Havana city 40 000 inhabitants are exposed to coastal
floods, and at present mitigation and adaptation measures are applied.
Coastal settlements vulnerability
Main vulnerability factors are:
-Proximity to shoreline and coast type
-Settlement size and number of inhabitants
-Conditions and type constructive of dwellings
-Accessibility
-Population and dwellings located below 1 meter high
-Economic base
-Technical infrastructure
In our case, the 84% of these settlements and more than 97% of the coastal population are located in
the first 200 m from the shoreline. Mostly on accumulative low coasts.
The majority of dwellings are in a regular or bad constructive conditions.
The economical base of coastal settlements is the decisive factor for the proposal of adaptation
strategies. The majority of rurals settlements _118 with more than 43 000 inhabitans_ depend of
agricultural and forest activities, While main economic activities in the urban ones are port, fishery,
local or national tourism and more recently international tourism.
The presence of any type of technical infrastructure in a territory corresponds to the social and
economic necessities of the population. Their existence and state is in agreement with the development
of the settlement and the quality of life of their inhabitants The main difficulties of the technical
infrastructure are in the service of sewer and pluvial systems while fresh water depends on
underground basins, its quality varies from regular to good.
In spite of the difficulties existing with the aquifer next to the coasts, coming from open underground
basins with high level of dissolved salts in it. They don't constitute a great problems to the localization
of the population, because it has always been left to the search of other alternative in order to
guarantee the supply. This situation could vary with an increase of the sea level that would affect the
water quality of 23 underground basins supplying important coastal and non coastal settlements.
Study case, Santa Cruz del Sur
The study case is in Santa Cruz del Sur in the south coast of the central region.
This settlement is located in a very low plain (figure 8). It was founded in 1828 year to less than 0.5
meters high from sea level, in the beach zone. Later in 1932 year, it lost its population as you can see
in the graph of the dynamic growth (figure 9).
Fi Figure 8
Topography profile N-S of the location of Santa Cruz del Sur
Sor Source: Rodríguez et al., 2001
año
1999
1958
1932
1828
ha
0
ha
50
100
150
200
250
1828
1931
1932
1940
1958
1975
1999
0
19
0
24
5 3 .5
150
216
Figure 9 Dynamic growth
Source: Rodríguez et al., 2001
A surge tropical hurricane was the cause of physical
disappearance of the settlement and the death of more than
3000 persons in 1932 year . The surge was of 7 meters
high, was the
most surge dangerous in Cuba.
Nowadays its probability of occurrence is once every
333 years.