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.