Every now and then
I take a walk along the beach, about 200 meters from where I reside. And each
time I took the walk I realized that a small cove that was on the beach when I
was young is no more there. I am talking about Jomo n∫ↄↄnaa. Jomo is the name
of the area, on the gulf of Guinea , n∫ↄↄnaa is a Ga language meaning the
entrance to the sea or edge of the sea. In English it means Jomo beach. The Gas
is an ethnic group in Ghana; specifically the Abafum people of La are natives
of Jomo. So the cove on Jomo beach is no more there; the waves have chipped it
away. The cove has been lost to coastal erosion!
Year by
year, West Africa's coast is retreating. By how much depends, said Kwasi
Appeaning Addo, a lecturer in coastal processes at the University of Ghana.
Around
Ghana's capital Accra, the coast is eroding at one-and-a-half metres per-year,
while in the eastern coast around Totope it's three meters per-year, Addo said.
When the weather is rough, Agbakla said the waves
near the village can claim as much as ten meters a year. Agbakla is chief of
Totope.
I will use the Jomo
cove as a stepping stone to cite more instances and assign general causes.
INSTANCES
The Dutch were the first to open trade
between Europe and Ada in the 16th century and built a new trading post here in
1775. Later, the Danes took over, who at this time had power over the whole
coast east of Accra. They
remained in Ada for more than 100 years and had business relationships with the
locals. To defend their trading post against the attacking neighboring tribes,
the Danes built Fort Kongenstein in 1783.[1] This fort
actually gave Ada Foah its name: Ada Fort, village of the fort.
Today, Ada is a shadow of its former self as
far as social life and economic activities are concerned. There are hardly any
traces of physical structures such as forts, factories and shops remaining,
since large parts of the town have been eroded and washed
into the sea.
Accra scientist Kwasi Appeaning Addo warns that other
coastal castles facing the threat of erosion include Cape Coast (south-west of
the capital), and Osu in the greater Accra area – both UNESCO World Heritage
sites. Addo believes that the castle at Osu may be flooded by 2050.
Totope, Ghana - Ask anyone in this fishing village
along Ghana's eastern coast where they grew up, and they'll likely point south,
towards the blue waves of the Gulf of Guinea.
The ocean has
encroached on areas that were once land, dry enough for the villagers of Totope
to grow crops, build homes and raise families.
It's all gone now(2013),
buried by crushing waves and shifting sands that have forced the village of a
few thousand to move onto swampy land reclaimed with an unreliable mix of sand
and trash.
"The future of Totope looks very,
very bleak," the village's chief Theophilus Agbakla said.
Dunwich, the capital of the English medieval wool trade, disappeared over the period of a few centuries due to
redistribution of sediment by waves.
The Holderness coastline on the east coast of England,
just north of the Humber
Estuary, is one of the
fastest eroding coastline in Europe due to its soft clay cliffs and powerful
waves.
Fort Ricasoli, a historic 17th century fortress in Malta is being threatened by coastal erosion, as it was built on a fault in the
headland which is prone to erosion. A small part of one of the bastion walls
has already collapsed since the land under it has eroded, and there are cracks
in other walls as well.
Leatherman (National Healthy Beaches Campaign) cites U.S.
Environmental Protection Agency estimates that between 80 and 90 percent of the
sandy beaches along America’s coastlines have been eroding for decades. In many of these cases, individual beaches
may be losing only a few inches per year, but in some cases the problem is much
worse. The outer coast of Louisiana, which Leatherman refers to as “the erosion ‘hot spot’
of the U.S.,” is losing some 50 feet of beach every year.
This country (Maldives) “could become the first state in history
to be completely erased by the sea,” says Evan Puschak of the Seeker Network. It’s the
planet’s lowest country. “On average, it’s only five feet above sea level,”
says Puschak. If the oceans continue to rise, as predicted, 77 percent of this country will
be under water by the end of the century. If the rate of rise increases even
more, as a new study suggests, the country
could even be submerged by 2085.
It’s not just low-lying island nations either. “A recent study
says we can expect the oceans to rise between 2.5 and 6.5 feet (0.8 and 2
meters) by 2100, enough to swamp many of the cities along the U.S. East Coast,”
says National Geographic. “More dire estimates, including
a complete meltdown of the Greenland ice sheet, push sea level rise to 23 feet
(7 meters), enough to submerge London.”
CAUSES:
SEA LEVEL RISE
A world-wide sea level rise is a phenomenon, which has been discussed for
decades. A global sea level rise of 0.1 to 0.25 m was recorded over the last
century. The forecast for the global sea level rise for the next century varies
considerably; however, with a central estimate of 0.2 m and 0.5 m at the middle
and end of the 21st century, respectively, according to Intergovernmental Panel
on Climate Change, IPCC. An increasing sea level will cause a shoreline
setback, which is approximately equal to the sea level rise divided by the
slope of the active coastal profile, when considering equilibrium profiles.
Consider, for example, a sea level rise of 0.5 m and an equilibrium coastal
profile with a slope of the shore face and the shore of 1/100. The setback
caused by such a sea level rise will be 50 m. Littoral coasts consisting of
fine sediments will be exposed to higher setbacks than coasts consisting of
coarser sediments.
NATURAL VARIATION
The natural variation in the supply of sand to a coastline from a river can
contribute to erosion. Droughts in large river basins can result in long
periods with decreasing supplies of sand to the shoreline, leading to shore erosion.
The historic large variations in the shorelines of the Nile delta were partly
due to this situation, whereas the more recent erosion is mainly the result of
human interventions along the Nile.
SAND
MINING
Sand mining occurs when people
scoop sand from the beaches mainly for construction. It is ‘supposedly’ illegal
in Ghana. However, people have persisted in this venture dating back to the
pre-independence era.
This
activity has been identified to be widespread across all four coastal regions
in Ghana.
Along
the Moree to Elmina stretch of coastline, almost every pocket of sandy beach is
mined by commercial contractors or by groups of individuals who either pack
them in bags before transporting or mould blocks on the beaches for sale.
Currently(April
02, 2014) up to eight tipper truck-based sand mining sites are dotted along the
25km Moree, Cape Coast and Elmina coastline, with some of these sites recording
in excess of 70 tipper truck lifting each day according to a recent study. Coasts
perform important regulatory, ecological and economic functions.
One
such function is the natural protection for coastal properties against storms
and the full force of the sea. When sand is taken from the coast, coastal
communities, especially those in low-lying areas, are made vulnerable to
flooding.
Currently,
several coastal communities across the country experience the intrusion of the
sea in their homes during storms and, especially, the rainy season. If we are to
investigate, we will establish that most of these communities have engaged in
beach sand winning in the past and sometimes continue to do so even as their
homes are flooded seasonally. In Cape Coast and its surrounding coastal
communities where tourism is a major part of the local economy, sand mining has
contributed to the degradation that is evident on most of the beaches.
SUBSIDENCE
Subsidence lowers the surface in a specific
region. Subsidence is a local/regional phenomenon in contrast to the sea level
rise, which is global. Subsidence can be caused by many different phenomena,
natural as well as human. Natural causes can be the settling of soft sediments,
tectonic activity and different kinds of rebound processes, whereas human
causes can be the extraction of groundwater, oil or gas in the coastal area.
Subsidence acts in the same way as sea level rise in relation to shore erosion
apart from the fact that a sea level rise will always be a gradual and slow
process, whereas subsidence may occur rapidly depending on the cause of the
subsidence.
DAMMING
Sediment flows in Ghana
and elsewhere have been disrupted by the damming of rivers. Beaches
around Totope rely on sediment from the Volta River, Addo said, but that flow
was disrupted by the construction of the Akosombo dam in 1965, which provides
most of the electricity for Ghana.
"Now that we
have blocked it over decades…we are experiencing the consequences," Addo
said. "
The whole thing is a matter of cause and effect. If the cause is removed
there will be no effect.
Source:
http://aljazeera.com/indepth/features/2013/12/
http://ecowatch.com/2015/5/22/maldives-underwater
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