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CHAPTER ONE

INTRODUCTION

Among the major problems facing mankind today, is the issue of climate change and variability. Climate change has long-since ceased to be a scientific curiosity, and no longer a mere environmental and regulatory concerns but a major, overriding environmental issue of our time, and the single greatest challenge facing environmental regulators (Odjugo, 2011).  It is also a growing crisis with economic, health and safety, food production, security and other dimension.  It should be noted that climate change is linked to human actions, and in particular from the burning of fossil fuels and changes in global patterns of land use.  Also, due to the human-induced increase of atmospheric greenhouse gas concentrations, various impacts have been observed (Wardekker, 2011)

 However, major consequences of climate change and variability are mainly felt at regional levels with continuous impact on the environment as it relates to global temperatures, water resources, ecosystems, agriculture and health, among others.  For example, over the past century (1906-2005), global average surface temperatures have increased by 0.74±0.18°C (IPCC, 2007).  This is based on observations of air and ocean temperatures and changes, snow/ice extent and sea level.  The evidence is that the Earth is warming and that future global climate and environmental circumstances may be significantly different from today.  Hence, there is need for an appropriate adaptation technique with potential to avoid adverse climate change consequences.

Global climate changes are also expected to affect coastal communities around the world, many of which are already considered vulnerable to ongoing climate variability (IPCC, 2001; Ogbuene, 2011). Lagos coastal region due to its location and topography is particularly vulnerable to the impacts of climate change. Of these changes, accelerated sea-level rise has received much attention and may entail elevated tidal inundation, increased flood frequency, accelerated erosion, rising water tables, increased salt water intrusion and a suite of ecological changes(Odjugo, 2001a)

In addition, the Intergovernmental Panel on Climate Change (IPCC) recognises the Nigerian coast as one of the low-lying coasts in West Africa which is likely to experience severe effects from flooding as a result of rising sea levels and climate change.  The low nature and the topography of the entire Nigerian coastline area render the area very susceptible to flooding especially at high tides and during the rainy season (Nicholls and Mimura, 1998).

Lagos coastal region has experienced significant land cover changes due to fast and present reclamation activities to secure more and more land for urban development (Odjugo, 2009a).  Land reclamation achieved through filling up of swamps and floodplains, destruction of mangroves and wetlands have generally reduced the flood storage capacity of the urban land (Anika, 2010). Rapid and largely unplanned urban growth has resulted in land use changes and subsequent changes in the hydrological fluxes in the urban watershed thereby increasing flood hazard and risk in many parts of the metropolis (Anyadika, 2009). This makes the rapidly urbanizing area and the growing population vulnerable to sea level rise and climate change (Ayoade and Akintola, 1980).  Hence, due to the detrimental effect of climate change on physical and biological systems, coping with climate change remains a daunting challenge.

 Hence this study attempts to access climate change and variability in Lagos coastal region.

PROBLEM IDENTIFICATION

Climate change is to a great extent induced by human activities that causes variability in the intensity of heat burning the earth surface and the degree of rainfall for long period.  This could provoke dangerous implications to vulnerable Lagos coastal regions because it is prone to sea-level rise and extreme weather events which include:

(a)    Wetlands and lowlands inundation: Wetlands in Lagos coastal region consist of the dominant brackish water mangrove swamps and marshes and rainforest swamps and marshes (Ibe, 1990).  A sea level rise will inundate these wetlands with sea water through the many tidal inlets that characterize the Lagos coastline which will adversely affect the mangrove ecosystem and its inhabitant.  Loss of wetlands could also occur whereby wetlands do no longer function as natural buffer to flooding.

(b)    Shorelines erosion (Plate 2): An accelerated rise in sea level will be accentuated by the phenomenon of subsidence which would aggravate the existing ecological problems associated with coastal erosion resulting in loss of wetlands and creating threats to most socio-economic installations on or near the coastline and increase flood risk. 

(c)    Exacerbate coastal flooding (Plate 1): Increase precipitation and thermal expansion of sea will raise the sea level resulting in flooding of low lying beaches.  This will automatically cause flooding in the adjacent coastal areas, cities and inhabited islands.  This is expected to even become more threatening whenever storm surges coincide with spring tides (Kron, 2008).

(d)   Salt water intrusion: Rising sea levels also increase the salinity of groundwater and push salt water further upstream.  This salinity may make water undrinkable without desalination, and harms aquatic plants and animals that cannot tolerate salinity.

(e)    Change the heights, frequencies and other characteristics of waves among others

 These effects have enormous environmental, social, cultural, economic and financial implications for the coastal areas. Hence a participatory approach by various stakeholders involved in Lagos coastal region towards implementation of adaptation techniques will be needful for sustainable development of the region.

 Plate 1: Flooding of Lagos city after a heavy rain

       Source: (BNRCC, 2008)

Plate 2: Eroded shorelines of Alpha Beach, Lagos

Source (Vanguard Newspaper, October 9, 2012)

Plate 3: Coastal Erosion threatened by Atlantic Ocean, Lagos

Source (Vanguard Newspaper, October 9, 2012)

Plate 4: Atlantic Ocean Surge at Kuramo Beach, Lagos.

Source (Premium Times, August 21, 2012)

Plate 5: Lagos, February 13, 2012 Rainstorm

Source: Lagos State Environmental Protection Agency 4th Summit Presentation

1.2: SIGNIFICANCE OF STUDY

Worldwide, coastal areas are the most exploited in terms of urbanization due to their abundance in natural resources that can provide humans with many ecosystem services that are important to support livelihoods and economic activities (Kron, 2008).

  The level of disturbance and effect of urbanization on natural process in coastal regions are fast becoming a nightmare, some of which are expected to become more serious due to changing climate (Satterthwaite, 2010).

  Hence, this study examines and analyzes climate change and variability in Lagos coastal region using temperature and rainfall measurement as a parameter over a specific duration (30years). This study also highlights the impacts of climate change to coastal regions that invariably may contribute to accentuated environmental disasters and the exacerbation of health risks.

AIM AND OBJECTIVES OF THE STUDY.

AIM

The aim of this study is to assess the climate trends for Lagos region and the consequences on the coastal environment in order to develop an appropriate climate change adaptation strategies for Lagos coastal region.

OBJECTIVES.

The specific objectives are:

v  To examine the rainfall and temperature trend in Lagos region (1981-2010)

v  To assess the relative consequences of the climatic trends socio-economic activities and environment in Lagos region.

v  To evaluate appropriate adaptation strategies towards sustainable Lagos coastal environment.

STUDY AREA

GEOGRAPHICAL BACKGROUND

Lagos, a state in Nigeria is the study area of this research.  It is a commercial centre in Nigeria with a total of about 17 million inhabitants, a yearly growth rate of 3.2% and second most populous city in the country (Census, 1996).  It is the fifth largest city in the world, is the foremost manufacturing and port city in West Africa, and the hub of business and economic development in Nigeria (BNRCC, 2012)

   This coastal city is situated within latitude 6°23’N and 6°41’N and longitude 2°42’E and 3°42’E (Fig 1).

Figure 1: Lagos Coastal City (Source: Vulnerability of Poor Urban Coastal Communities to Climate Change in Lagos, Nigeria. Fifth Urban Research Symposium 2009

Lagos State is situated in south western Nigeria, bordered in the north and east by Ogun State, in the west by the Republic of Benin and in the south by the Atlantic Ocean.  The state has an area of approximately 3,345 square kilometres, which is about 0.4% of the total area of Nigeria (Fig 1).

Lagos State has a coastline of approximately 180km, underlined by sedimentary rocks; the state is on a coastline plain characterized by predominantly flat terrain, with an average elevation of less than 1.5m above sea level (BNRCC, 2012a).  The land slopes gently from the interior to the sea.  Water bodies and wetlands cover over 40% of the total land area of the state and an additional 12% is subject to seasonal flooding (BNRCC, 2012b).  The coastal areas consist of a complex belt of barrier islands with active ocean, beaches, lagoon and lagoon beaches, lagoon inlets, creeks, rivers, swamps and sandy uplands and plains.  The importance of the coastal zone lies in the fact that it is not only already heavily urbanized but rapid urbanization is continuing, exposing people, infrastructure and tourism industry to greater risk of climate change impact, particularly seal level rise (Okude and Ademiluyi, 2006).

CLIMATE.

The climate of Lagos state is the wet equatorial type due to its nearness to the equator and the Gulf of Guinea. Lagos is located partly in the swampy mangrove and partly rainforest regions of West Africa with annual maxima bi-modal rainfall.  It receives mean annual rainfall of about 2000mm (Ojo et al., 2004). Lagos has a tropical savannah climate that is similar to that of the rest of southern Nigeria.  There are two rainy seasons, with heaviest rains falling from April to July and a weaker rainy season in October and November.  There is a brief relative dry spell in August and a longer dry season from December to March.  The main dry season is accompanied by harmattan winds from the Sahara Desert, which between December and early February can be quite strong. Lagos state has consistently high temperatures, with the mean monthly maximum temperature of about 30°C (Iwugo et al., 2003).

ECO-REGIONS AND ECOLOGICAL FEATURES OF LAGOS STATE.

The eco-regions of Lagos State and their features are summarized in Table 1.  Wetlands and upland forest (Rainforest) are the dominant ecozones.  In fact, the state falls within the Tropical Rainforest zone, but the vegetation cover in areas that are not built up is mostly a mosaic of mangrove swamps, fresh water swamps, secondary forest, farmland and fallow land.  The topography is gently sloping throughout and the soils are mostly deep and poorly drained (FDALR, 1995)

Table 1.4.3: Eco-regions of Lagos State and their Ecological Features

Eco-region

Geology

Topography

Soil features

Ecozone

Badagry, Ibeju-

Lekki, Ojo, Lagos

Island, Surulere,

Eti-Osa and areas

close to the coast

Deltaic basis

and tidal

flats

Nearly level

plains of 1-2 %

slope

Very deep, poorly drained and moderately well drained soils; sandy, sandy loamy or sandy clay loam surfaces over sandy clay, loam sub soils.

Wetland

Part of Ebutemetta,

Mushin and

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ASSESSMENT OF CLIMATE CHANGE AND VARIABILITY IN COASTAL REGION

CHAPTER ONE

INTRODUCTION

Among the major problems facing mankind today, is the issue of climate change and variability. Climate change has long-since ceased to be a scientific curiosity, and no longer a mere environmental and regulatory concerns but a major, overriding environmental issue of our time, and the single greatest challenge facing environmental regulators (Odjugo, 2011).  It is also a growing crisis with economic, health and safety, food production, security and other dimension.  It should be noted that climate change is linked to human actions, and in particular from the burning of fossil fuels and changes in global patterns of land use.  Also, due to the human-induced increase of atmospheric greenhouse gas concentrations, various impacts have been observed (Wardekker, 2011)

 However, major consequences of climate change and variability are mainly felt at regional levels with continuous impact on the environment as it relates to global temperatures, water resources, ecosystems, agriculture and health, among others.  For example, over the past century (1906-2005), global average surface temperatures have increased by 0.74±0.18°C (IPCC, 2007).  This is based on observations of air and ocean temperatures and changes, snow/ice extent and sea level.  The evidence is that the Earth is warming and that future global climate and environmental circumstances may be significantly different from today.  Hence, there is need for an appropriate adaptation technique with potential to avoid adverse climate change consequences.

Global climate changes are also expected to affect coastal communities around the world, many of which are already considered vulnerable to ongoing climate variability (IPCC, 2001; Ogbuene, 2011). Lagos coastal region due to its location and topography is particularly vulnerable to the impacts of climate change. Of these changes, accelerated sea-level rise has received much attention and may entail elevated tidal inundation, increased flood frequency, accelerated erosion, rising water tables, increased salt water intrusion and a suite of ecological changes(Odjugo, 2001a)

In addition, the Intergovernmental Panel on Climate Change (IPCC) recognises the Nigerian coast as one of the low-lying coasts in West Africa which is likely to experience severe effects from flooding as a result of rising sea levels and climate change.  The low nature and the topography of the entire Nigerian coastline area render the area very susceptible to flooding especially at high tides and during the rainy season (Nicholls and Mimura, 1998).

Lagos coastal region has experienced significant land cover changes due to fast and present reclamation activities to secure more and more land for urban development (Odjugo, 2009a).  Land reclamation achieved through filling up of swamps and floodplains, destruction of mangroves and wetlands have generally reduced the flood storage capacity of the urban land (Anika, 2010). Rapid and largely unplanned urban growth has resulted in land use changes and subsequent changes in the hydrological fluxes in the urban watershed thereby increasing flood hazard and risk in many parts of the metropolis (Anyadika, 2009). This makes the rapidly urbanizing area and the growing population vulnerable to sea level rise and climate change (Ayoade and Akintola, 1980).  Hence, due to the detrimental effect of climate change on physical and biological systems, coping with climate change remains a daunting challenge.

 Hence this study attempts to access climate change and variability in Lagos coastal region.

PROBLEM IDENTIFICATION

Climate change is to a great extent induced by human activities that causes variability in the intensity of heat burning the earth surface and the degree of rainfall for long period.  This could provoke dangerous implications to vulnerable Lagos coastal regions because it is prone to sea-level rise and extreme weather events which include:

(a)    Wetlands and lowlands inundation: Wetlands in Lagos coastal region consist of the dominant brackish water mangrove swamps and marshes and rainforest swamps and marshes (Ibe, 1990).  A sea level rise will inundate these wetlands with sea water through the many tidal inlets that characterize the Lagos coastline which will adversely affect the mangrove ecosystem and its inhabitant.  Loss of wetlands could also occur whereby wetlands do no longer function as natural buffer to flooding.

(b)    Shorelines erosion (Plate 2): An accelerated rise in sea level will be accentuated by the phenomenon of subsidence which would aggravate the existing ecological problems associated with coastal erosion resulting in loss of wetlands and creating threats to most socio-economic installations on or near the coastline and increase flood risk. 

(c)    Exacerbate coastal flooding (Plate 1): Increase precipitation and thermal expansion of sea will raise the sea level resulting in flooding of low lying beaches.  This will automatically cause flooding in the adjacent coastal areas, cities and inhabited islands.  This is expected to even become more threatening whenever storm surges coincide with spring tides (Kron, 2008).

(d)   Salt water intrusion: Rising sea levels also increase the salinity of groundwater and push salt water further upstream.  This salinity may make water undrinkable without desalination, and harms aquatic plants and animals that cannot tolerate salinity.

(e)    Change the heights, frequencies and other characteristics of waves among others

 These effects have enormous environmental, social, cultural, economic and financial implications for the coastal areas. Hence a participatory approach by various stakeholders involved in Lagos coastal region towards implementation of adaptation techniques will be needful for sustainable development of the region.

 Plate 1: Flooding of Lagos city after a heavy rain

       Source: (BNRCC, 2008)

Plate 2: Eroded shorelines of Alpha Beach, Lagos

Source (Vanguard Newspaper, October 9, 2012)

Plate 3: Coastal Erosion threatened by Atlantic Ocean, Lagos

Source (Vanguard Newspaper, October 9, 2012)

Plate 4: Atlantic Ocean Surge at Kuramo Beach, Lagos.

Source (Premium Times, August 21, 2012)

Plate 5: Lagos, February 13, 2012 Rainstorm

Source: Lagos State Environmental Protection Agency 4th Summit Presentation

1.2: SIGNIFICANCE OF STUDY

Worldwide, coastal areas are the most exploited in terms of urbanization due to their abundance in natural resources that can provide humans with many ecosystem services that are important to support livelihoods and economic activities (Kron, 2008).

  The level of disturbance and effect of urbanization on natural process in coastal regions are fast becoming a nightmare, some of which are expected to become more serious due to changing climate (Satterthwaite, 2010).

  Hence, this study examines and analyzes climate change and variability in Lagos coastal region using temperature and rainfall measurement as a parameter over a specific duration (30years). This study also highlights the impacts of climate change to coastal regions that invariably may contribute to accentuated environmental disasters and the exacerbation of health risks.

AIM AND OBJECTIVES OF THE STUDY.

AIM

The aim of this study is to assess the climate trends for Lagos region and the consequences on the coastal environment in order to develop an appropriate climate change adaptation strategies for Lagos coastal region.

OBJECTIVES.

The specific objectives are:

v  To examine the rainfall and temperature trend in Lagos region (1981-2010)

v  To assess the relative consequences of the climatic trends socio-economic activities and environment in Lagos region.

v  To evaluate appropriate adaptation strategies towards sustainable Lagos coastal environment.

STUDY AREA

GEOGRAPHICAL BACKGROUND

Lagos, a state in Nigeria is the study area of this research.  It is a commercial centre in Nigeria with a total of about 17 million inhabitants, a yearly growth rate of 3.2% and second most populous city in the country (Census, 1996).  It is the fifth largest city in the world, is the foremost manufacturing and port city in West Africa, and the hub of business and economic development in Nigeria (BNRCC, 2012)

   This coastal city is situated within latitude 6°23’N and 6°41’N and longitude 2°42’E and 3°42’E (Fig 1).

Figure 1: Lagos Coastal City (Source: Vulnerability of Poor Urban Coastal Communities to Climate Change in Lagos, Nigeria. Fifth Urban Research Symposium 2009

Lagos State is situated in south western Nigeria, bordered in the north and east by Ogun State, in the west by the Republic of Benin and in the south by the Atlantic Ocean.  The state has an area of approximately 3,345 square kilometres, which is about 0.4% of the total area of Nigeria (Fig 1).

Lagos State has a coastline of approximately 180km, underlined by sedimentary rocks; the state is on a coastline plain characterized by predominantly flat terrain, with an average elevation of less than 1.5m above sea level (BNRCC, 2012a).  The land slopes gently from the interior to the sea.  Water bodies and wetlands cover over 40% of the total land area of the state and an additional 12% is subject to seasonal flooding (BNRCC, 2012b).  The coastal areas consist of a complex belt of barrier islands with active ocean, beaches, lagoon and lagoon beaches, lagoon inlets, creeks, rivers, swamps and sandy uplands and plains.  The importance of the coastal zone lies in the fact that it is not only already heavily urbanized but rapid urbanization is continuing, exposing people, infrastructure and tourism industry to greater risk of climate change impact, particularly seal level rise (Okude and Ademiluyi, 2006).

CLIMATE.

The climate of Lagos state is the wet equatorial type due to its nearness to the equator and the Gulf of Guinea. Lagos is located partly in the swampy mangrove and partly rainforest regions of West Africa with annual maxima bi-modal rainfall.  It receives mean annual rainfall of about 2000mm (Ojo et al., 2004). Lagos has a tropical savannah climate that is similar to that of the rest of southern Nigeria.  There are two rainy seasons, with heaviest rains falling from April to July and a weaker rainy season in October and November.  There is a brief relative dry spell in August and a longer dry season from December to March.  The main dry season is accompanied by harmattan winds from the Sahara Desert, which between December and early February can be quite strong. Lagos state has consistently high temperatures, with the mean monthly maximum temperature of about 30°C (Iwugo et al., 2003).

ECO-REGIONS AND ECOLOGICAL FEATURES OF LAGOS STATE.

The eco-regions of Lagos State and their features are summarized in Table 1.  Wetlands and upland forest (Rainforest) are the dominant ecozones.  In fact, the state falls within the Tropical Rainforest zone, but the vegetation cover in areas that are not built up is mostly a mosaic of mangrove swamps, fresh water swamps, secondary forest, farmland and fallow land.  The topography is gently sloping throughout and the soils are mostly deep and poorly drained (FDALR, 1995)

Table 1.4.3: Eco-regions of Lagos State and their Ecological Features

Eco-region

Geology

Topography

Soil features

Ecozone

Badagry, Ibeju-

Lekki, Ojo, Lagos

Island, Surulere,

Eti-Osa and areas

close to the coast

Deltaic basis

and tidal

flats

Nearly level

plains of 1-2 %

slope

Very deep, poorly drained and moderately well drained soils; sandy, sandy loamy or sandy clay loam surfaces over sandy clay, loam sub soils.

Wetland

Part of Ebutemetta,

Mushin and