NIGERIA: More Than 3 Million May Have to Move from
Lowlands in Nigeria
Nigeria's coast has a low slope, and the Niger delta, the largest
Africa, is flatter still. With sea level rise, inundation along
the coast would extend many kilometers inland and perhaps 100
km up the delta, bringing serious consequences to the people and
the economy.
An estimated 25 million people, 28 percent of the population,
live along the coast, more than a third below the two meter inundation
zone. Two thousand industrial establishments, 85 percent of the
country's total, as well as a majority of the oil exploration
and exploitation facilities, are concentrated on this lowland.
The nation's largest city, Lagos, the former capital, is expanding
rapidly on ground often no more than one meter above sea level
and subject to periodic flooding. The Niger delta contains the
wetlands and lagoons which are the spawning grounds for commercial
shrimp and oysters, and bait fish for the large tuna industry.
And it is the site of 1300 oil wells which generate 90 percent
of export and foreign exchange oil earnings.
A one meter sea level rise would flood 18,000 km2. There is a
potential for a massive environmental refugee migration - as many
as 3.2 million people (about 3.5 percent of the population) -
from the many villages in the low-lying areas. Rivers fields and
villages would drain more slowly as floods became more frequent,
particularly during the May - September rainy season. Even with
total protection, extensive marsh and mangrove swamps would be
lost, significantly decreasing fish stocks. Flooding would destroy
$18 billion of infrastructure including the cost of drilling oil
wells.
Unless there is major investment in drainage facilities, Lagos
would suffer periodic floods. Saltwater would intrude further,
possibly contaminating aquifers throughout the region. The coastal
population depends heavily on groundwater; sixty percent of Lagos'
daily water demand is from a shallow, unconfined aquifer.
The cost of protecting the nation's developed coastal areas for
50 years (2051-2100) would amount to 0.2 - 0.3 percent of GNP.
Protection of moderately developed areas (total protection), would
amount to $1.4 - $1.8 billion and would include the cost of relocating
600,000 people from areas such as the Niger Delta and Mahin Mud
Coast which could not feasibly be protected. A large area of wetlands
-17,000 km2 - would be lost.
The impacts described above assume current population patterns
and development levels . But the following trends presage rapid
expansion in the coming century:
-
high birth rates
-
greater coastal development, especially in the oil industry
-
immigration from neighboring countries
-
increased rural development programs especially with the
need to feed the growing population
Protective measures appear likely and are feasible for
much of the population and facilities at risk as they are concentrated
in towns. Sea walls along the Barrier Coast (where Lagos is situated),
both on the Atlantic and inland shores, will be a major cost.
Protection of the Delta oil wells, worth $13 billion, adds signifcantly
to costs. Possibly new drilling technologies and the inclusion
of assumptions about sea level rise in the drilling of wells would
keep some protection costs down. The major harbors which are crucial
to the economic health of the country must be upgraded. Most tourism
has not reached the stage where extensive beach nourishment will
be necessary. But Bar Beach, near Lagos on Victoria Island, has
among the steepest erosion rates in Nigeria, averaging 25-30 meters
per year. A highly developed tourist facility, it would need help
to keep its sandy beach a major attraction.
(Gregory T. French, University of Maryland, USA, and Larry
F. Awosika and C.E. Ibe, Nigerian Institute for Oceanography and
Marine Research, Nigeria)
