GMES-&-Africa-UG/CVI-BULL/052020/002

Contact: The Director, Regional Marine Centre, University of Ghana P. O. Box LG.99, Legon, Ghana. Email: rmc@ug.edu.gh ; Website: https://gmes.ug.edu.gh/

MARINE AND COASTAL AREAS MANAGEMENT IN WESTERN AFRICA

GLOBAL MONITORING FOR ENVIRONMENT AND SECURITY (GMES),

& AFRICA PROGRAMME

APRIL, 2020

COASTAL VULNERABILITY OF WEST AFRICA

April 2020

Regional Marine Centre, University of Ghana Coastal Vulnerability Service

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TABLE OF CONTENTS

TABLE OF CONTENTS ................................................................................................................................ 1

INTRODUCTION ........................................................................................................................................ 2

COASTAL DYNAMICS ................................................................................................................................ 2

SHORELINE CHANGE OF WEST AFRICA .................................................................................................... 3

POLICY IMPLICATIONS AND RECOMMENDATIONS................................................................................. 4

CONCLUSION ............................................................................................................................................ 5

ACKNOWLEDGEMENTS ............................................................................................................................ 5

FURTHER READING ................................................................................................................................... 6

Regional Marine Centre, University of Ghana Coastal Vulnerability Service

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INTRODUCTION

Shoreline monitoring is important for ensuring the protection of coastal areas and providing information

on the dynamics of the coast. Shorelines change within short to long term periods and it is important that

monitoring mechanisms are put in place to allow provision of timely information on the evolution of the

coast. The coast provides an enabling environment for diverse economic activities, including tourism, fish

landing, habitats for fauna and flora, among others. In light of the benefits derived from the coast, coupled

with the threats of rapid erosion in the face of changing climate, an approach is required to address these

challenges. It is in line with this objective that the GMES and Africa Programme at the University of Ghana

is coordinating efforts in the twelve ECOWAS coastal countries to provide information to coastal managers

and relevant decision making bodies. This effort makes use of suite of oceanographic datasets obtained

from national institutions, international collaborators, and open source domains.

COASTAL DYNAMICS

The changes in the coastal zone areas are mostly caused by nearshore processes, beach morphology and

anthropogenic activities. Regular engineering and development activities along coastal areas and naturally

occurring phenomena near the coasts induce changes on coastal landforms. Urbanization, global

warming, climate change and sea-level rise engender coastal hazards that lead to drastic changes along

the coast (Joevivek et al., 2013). Globally, due to climate change the coast is constantly affected by

flooding, accelerated sea-level rise with elevated tidal inundation, accelerated erosion, rising water tables

and increased saltwater intrusion (Balica et al., 2012). According to the current Intergovernmental Panel

on Climate Change (IPCC), globally averaged sea rise of over 30 cm is expected to occur within this century.

Storms are expected to become intense with increased wind speeds. Over-washing and overtopping by

waves will cause frequent flooding events which will impact severely on coastal communities.

Computation of an index of coastal vulnerability which incorporates key parameters of geo-physical,

economic, social factors provides an objective way for coastal managers to make appropriate

interventions in the midst of limited resources and competing demands.

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SHORELINE CHANGE OF WEST AFRICA

The area under consideration spans the coast of Senegal in the north west of Africa to down to Cameroon

in the south. This region is very dynamic within the context of morphological processes influenced by

human activities. Data for computation of shoreline rate of change was obtained from Copernicus

Sentinel-1 data of May 2015 and December 2018. Pre-processing of the data was carried out using the

SNAP toolbox and then with QGIS. Shoreline change analysis was conducted with the open source AMBUR

software application which enabled calculation of shoreline End-Point-Rate (EPR) of change for

designated transects. Sections of the shoreline was validated using high resolution images acquired with

an unmanned aerial vehicle.

The results showed a general loss of land to the sea, with some areas experiencing high rates of erosion

interspersed with moderate accretion of sediments in some areas. From the analysis, it was observed that

the rate of erosion ranged between 1 m/year to about 30 m/year with an average rate of 10 m/year (±

0.5 m/year) (Figure 1). Notwithstanding this astronomical rate of loss of land to the sea, some areas also

recorded accretion up to about 10 m/year. However, some local areas recorded about 50 m/year (Figure

1). The countries that recorded the highest rates of erosion were Guinea, Nigeria, Liberia, Senegal, Guinea

Bissau and Ghana. The uncertainty in shoreline change obtained from sentinel-1 images using the adopted

methods for shoreline extraction was approximately 20 meters.

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Figure 1: Shoreline change rate map (in meters per year) of the entire coast of West Africa (Note: negative and positive values of colour range refer to erosion and accretion, respectively.

Information is also available at https://gmes.ug.edu.gh ).

POLICY IMPLICATIONS AND RECOMMENDATIONS

The findings in this report is very alarming!. In three and half years, as much as seventy to one hundred

meters (70 - 100 m) of beaches have been lost at some locations in West Africa. Other places also continue

to lose their beaches, although at a relatively lower rate. This means that in the next three to four years

many coastal communities will lose their dwellings to the sea. The impact of this would be enormous on

local economies, requiring governments to allocate resources to settle retreating communities. In

addition to losing taxes from the hospitality industry scattered along the beautiful beaches of West Africa,

fishing activities would also be negatively impacted. In Ghana, for example, the fisheries sector employs

about 2.4 million individuals or 10% of the population (NPOA, 2014). The artisanal fisheries is estimated

to contribute about 3% to national GDP and generate revenue of $341 million annually (Belhabib, 2015).

The story is similar in the other countries.

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The situation requires urgent policy actions to be taken by governments in the hope of mitigating the

impacts of shoreline recession – an action which must be tackled regionally. The following measures,

though not new, are pertinent in addressing the challenges confronting the region:

i. Development of a framework to initiate, expand, and /or improve the management of coastal

resources in safeguarding ecosystem health and human livelihoods;

ii. Strengthening existing legislations and policies to incorporate better marine spatial planning

strategies unique to each location within the context of the Blue Economy Agenda;

iii. Resource programmes that contribute to raising awareness of the public about climate

change and environmental threats, while building on existing indigenous knowledge and

value systems;

iv. Investment in soft engineering shoreline protection strategies in locations considered to be

of high value.

CONCLUSION

The Coastal Vulnerability Indices (CVI) service bulletin produced by the Regional Marine Centre provides

information on vulnerability of shorelines to users of the marine environment, especially policy makers,

coastal dwellers and Environment Managers for improved decision making on the use of coastal areas.

This service forms part of the Global Monitoring for Environment and Security (GMES) & Africa

programme. This issue focuses on shoreline change of the entire West African sub-region. It is targeted at

stakeholders of the marine environment, specifically policy makers, environment officers, researches,

private entities as well as interested individuals for planning purposes.

ACKNOWLEDGEMENTS

The Coastal and Marine Resources Management of Western Africa project is part of the continent-wide

Global Monitoring for Environment and Security, and Africa programme under the auspices of the African

Union Commission (AUC), and supported by the European Commission (EC). Satellite data used for

generating products in this bulletin were mainly obtained from the EU Copernicus programme. The

University of Ghana Consortium implementing the project in the 12 ECOWAS countries duly acknowledges

the kind support of the AUC and EC.

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FURTHER READING

Appeaning Addo, K., (2013). Assessing Coastal Vulnerability Index to Climate Change: The Case of Accra –

Ghana, Proceedings 12th International Coastal Symposium (Plymouth, England), Journal of Coastal

Research, Special Issue No. 65, pp. 1892-1897, ISSN 0749-0208.

Balica, S. F., Wright, N. G., Meulen, F. V. (2012) A flood vulnerability index for coastal cities and its use in

assessing climate change impacts. Nat Hazards (2012) 64:73–105.

Belhabib, D., U. Sumaila, and D. Pauly, Feeding the poor: Contribution of West African fisheries to

employment and food security. Ocean & Coastal Management, 2015. 111: p. 72-81.

Hegde, A.V. and Reju, V.R., (2007). Development of coastal vulnerability index for Mangalore coast, India.

Journal of Coastal Research, 23(5), 1106-1111. West Palm Beach (Florida), ISSN.

Joeviviek, V. and Saravanan, S., Chandrasekar, N. (2013). Coastal Vulnerability and Shoreline Changes for

Southern Tip of India- Remote Sensing and GIS Approach. J Earth Sci Clim Change 2013, 4:4.

National plan of action to prevent, deter, and eliminate illegal, unreported, and unregulated fishing.

Available from: ftp://ftp.fao.org/fi/DOCUMENT/IPOAS/national/Ghana/NPOA_IUU.pdf. 2014.

UN Economic Commissions of Africa (2016). Africa's Blue Economy: A policy handbook. Economic

Commission for Africa, Addis Ababa, Ethiopia. ISBN: 978-99944-61-86-8.

Disclaimer The University of Ghana Regional Marine Centre assumes no legal liability or responsibility for how this information is used. This publication has

been produced with the support of the European Union and African Union Commission. The contents of this publication are the sole responsibility

of the Regional Marine Centre and can in no way be taken to reflect the views of the European Union and the African Union.