Kenya’s
600 km coastline is fast succumbing to Mother Nature’s wrath and retaliatory attacks.
A single aerial view of the magnificent ocean and sandy beaches can give the
false impression that all is well but at a closer look it is possible to see
the degradation that is as a result of climate change.
The depletion of the ozone layer by the continued emission
of greenhouse gases like carbon has resulted in global warming as the sun rays reflecting
from the earth’s surface are blocked by the blanket of gases.
The increased temperature around the earth’s surface has led
to the melting of ice caps on mountains and thermal expansion of water masses
causing the rise in sea level.
Kenya has two tidal gauges one at the Fisheries jetty in Mkowe,
Lamu County and another at the Liwatoni jetty in Kilindini Harbor, Mombasa
County which are part of the Global Sea Level Observing System. The gauges that
are managed by the Kenya Marine and Fisheries Research Institute (KMFRI)
provide high quality standardized data from monitoring the sea levels.
According to KMFRI senior scientist Dr. Charles Magori the
gauges have each been fitted with different monitoring systems for redundancy
checks and to provide more credible data.
The set of data
recorded by the two tide gauges from 1986-2006 reveals that the sea level along
the coastline has had a gradual increase of 1.9 mm.
“Despite the gaps from unprecedented breakdown of the tide
gauges there is a continuous set of data that agrees with the global increase
trend of 2mm,” he said.
Despite the increase being considered negligible the impacts
on a global scale are far reaching affecting both terrestrial and marine biodiversity.
“It may look like a very small increase but oceans account
for 2/3 of the earth’s surface and that is an enormous volume of water which is
moving inland,” he noted
The most visible of these impacts has been the erosion of
land along the coastline. Many residents and hoteliers in low lying areas of
north coast and some in the south have experienced loss of land due to erosion.
“Unlike Mombasa
the northern banks of Malindi and Lamu are low lying areas and are more
vulnerable to the effects of sea level rising,” he explained
Ngomeni in Malindi is one such area with a serious erosion problem.
Buildings and trees have literally been swept away as the sea has gotten inland.
Accretion has also taken place though on a much smaller scale with buildup of
sand in areas that was once covered by the sea.
With each tidal excursion there is a salt water intrusion
into the ground water systems.as such those with dug boreholes end up having
more saline water than usual. Those dependent on such wells have to seek other
sources of water for use.
Marine biodiversity has not been spared either; eggs of
turtles that are laid on the sandy beaches are washed away and eaten by
predators. Deep sea creatures get stuck along the coastline after being washed
ashore during tidal excursions.
The warm temperatures deny the sea the much needed oxygen
leading to bleaching of coral reefs and reducing their ability to form
limestone skeletons.
Dr. Magori lamented that the impacts of sea level rising are
worse during springtide where waves are higher than normal.
“The tidal variation in spring tide is close to 4 meters
plus the general rises in sea level then the excursions are likely to be longer
with more intrusions inland,” he added.
An Intergovernmental Panel on Climate Change (IPCC) prediction
puts the sea level increase in the worst case scenario at 50 cm by 2050 and 100
cm at the end of the century.
This directly means that more water will be displaced inland
putting low lying islands across the world at a major risk of disappearance.
This would mean the vanishing of Lamu, Pate,Watamu,Wasini
and Kiunga islands which are major tourist attractions. The establishment and
enforcement of a comprehensive coastal zone management policy remains to be the
only solution for loss of land along the coastline.
Many of the hotels in north and south coast built close to
the ocean have already begun constructing sea walls to prevent further loss of
land through erosion but this according to Dr. Magori is not permanent reprieve
as some of the walls have been built without the consultation of coastal
engineers.
“Those sea walls will only help for a time; we need to set
up a legal framework that would enforce adherence to set back lines that will
prevent people from building too close to the ocean,” he reiterated.
Varying set back lines provide a safe distance for
construction and cultivation from the ocean’s high water mark depending on the
land’s topography and vulnerability. South Africa
has put up one such set back line of 200 meters in Durban
where construction of buildings to close to the sea is not allowed.
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