IMPACT OF CLIMATE CHANGE ON FLOODING PATTERNS IN NIGERIA: A CASE STUDY OF FLOODING EVENT IN VICTORIA ISLAND, LAGOS, IN 2024

CHAPTER ONE

INTRODUCTION

1.1 Background of the study

Climate change encompasses discernible alterations in the climate system that can be attributed to human activities, particularly those that modify the composition of the Earth's atmosphere and ultimately result in global warming (Yin, 2022). Global warming is strongly linked to climate change, particularly as a result of the interaction between natural and man-made greenhouse gases (GHGs). These GHGs are widely recognised as the main cause of the Earth's atmosphere and seas warming.

Global warming refers to the progressive rise in the average temperature of the Earth's atmosphere and seas (Sally, 2019). An alteration that is causing a permanent and irreversible transformation of the Earth's climate (Yin, 2022). Global warming is primarily caused by the amplified release of greenhouse gases (GHGs) resulting from various human activities. These activities include the combustion of fossil fuels such as oil, natural gas, and coal, as well as the burning of wood, wood products, and solid wastes. Other contributors include the raising of livestock, decomposition of organic wastes in landfills, combustion of solid wastes and fossil fuels in industrial and agricultural operations, bush burning, and deforestati These human activities disrupt the balance between natural greenhouse gases (water vapour, carbon dioxide, methane, and nitrous oxide) and man-made greenhouse gases (such as sulphur hexafluoride (SF), hydrofluorocarbons (HFCs), and perfluorocarbons (PFCs)) in the Earth's atmosphere. As a result, both the atmosphere and the oceans are warming because these gases trap heat (Yin, 2022). 

The concentration of these greenhouse gases has beyond the natural level (Sally, 2019). Scientific consensus confirms that the Earth's average temperature has increased by 0.4 to 0.8°C during the past century (Yin, 2022). The escalating emission of carbon dioxide and other greenhouse gases resulting from the combustion of fossil fuels, deforestation, agriculture, and other anthropogenic activities has been a significant cause of global warming over the past five decades (Yin, 2022). The anticipated consequences for the Earth's environmental equilibrium and global climate would encompass disturbances in temperature distribution, precipitation, evapo-transpiration, clouds, air currents, and subsequent alterations in vegetation zones. Additionally, there would be the thawing of polar ice caps, resulting in a rise in sea level and potential flooding that could have detrimental impacts on low-lying regions. These various effects would interact synergistically. These factors have serious consequences for the availability of fresh water resources, agriculture and food production, natural ecosystems, biodiversity, and human health (Ye, 2019).

Nigeria, situated in West Africa, has a wide range of climatic zones, spanning from dry areas in the north to tropical rainforests in the south. Due to its geographical location, socioeconomic problems, and low adaptive potential, the country is very susceptible to the impacts of climate change. The occurrence of floods in Nigeria can be attributed to significant climate-related issues such as rising temperatures, altering precipitation patterns, and escalating sea levels. Flooding has emerged as a prevalent environmental issue in Nigeria, causing severe harm to human livelihoods and infrastructure development (Adegun, 2023). Flooding frequently arises when a body of water traverses and inundates a land region. It is a phenomenon that is unique to many low-lying areas around the world, including Lagos State. Due to the continuous growth of urban population and the limited availability of dry lands, the State Government is facing the difficulty of dealing with issues such as encroachment, illegal structures, slum developments, and flooding. Lagos State can be characterised as an imperfect delta due to its sole estuary opening. The estuary referred to as the Commodore Channel, located at Onikan and near Bar Beach, serves as the outlet for the full volume of water from the Lagos Lagoon, Badagry Creek, Lekki Creek, and Ologe Lagoon, which is discharged into the Atlantic Ocean (Dube, Nhamo & Chikodzi, 2021).

Lagos is situated in a low-lying area, mostly below 17m in elevation, with several portions of the city at or below sea level (Lawson & Odunbaku, 2017; Yoade, Adeyemi & Adelabu, 2020). The topographical feature of Lagos, which is characterised by its flatness, hinders the rapid drainage of surface water. This, combined with the extensive use of impermeable paving, frequently leads to the rapid accumulation of standing water after heavy rainfall. The climate of Lagos is comparable to that of the remainder of Southern Nigeria, exhibiting two distinct rainy seasons: rainy season 1 (April – July) and rainy season 2 (October – November). The first season yields the most intense precipitation, therefore increasing the probability of floods. The average temperature is approximately 27 degrees Celsius, and the humidity can exceed 80%.

Adelekan's (2019) research provides valuable understanding of the growing vulnerability to flooding in Lagos. According to Yoade, Onifade, Olatunji, and Husseni (2023), based on their explanatory studies, Lagos is projected to be the fifth most vulnerable metropolis to climate change hazards by 2070. Lagos has been classified as one of the ten cities globally that face a significant risk from climate change, according to the Climate Change Vulnerability Index (CCVI) computation conducted by Fender in 2017. Climate change in Lagos has led to a significant escalation in the intensity and consequences of both interior and coastal floods (Huan & Manteghi, 2022).

The occurrence of flooding in Nigeria is not a novel occurrence; yet, the magnitude and recurrence of flood incidents have notably escalated in recent years (Aba, 2024). This can be ascribed to a confluence of natural and artificial forces, encompassing climate change, growing urbanisation, inadequate drainage systems, and deforestation. The floods have a profound and destructive effect, including loss of life, displacement of populations, destruction of infrastructure, and economic setbacks (Bassey et al., 2023). Victoria Island, a famous district in Lagos, Nigeria, has a long-standing vulnerability to floods. The 2024 flooding catastrophe in Victoria Island is a clear illustration of the deteriorating flooding situation intensified by climate change. This study examines the influence of climate change on the occurrence of floods in Nigeria, particularly the 2024 flooding incident at Victoria Island, Lagos.

1.2 Statement of the Problem

Flooding has been a recurring and destructive problem in Nigeria, causing substantial social, economic, and environmental consequences. Climate change has worsened the problem by modifying weather patterns and increasing the severity of flood episodes. Victoria Island in Lagos has had a progressive escalation in flooding occurrences in recent years, reaching its peak with the disastrous flooding incident of 2024. This case study tries to tackle the fundamental issues related to the influence of climate change on the occurrence of floods in Nigeria.

Lagos has a long history of experiencing different sorts of flooding, which has been widely recorded since the 1960s (Odunuga, 2008; Oyebande, 1974; Etuonovbe, 2011). This may have arisen from a climate shift that has been verified as genuine and existential, posing significant developmental difficulties and issues that require a national response. While some cultures have implemented strategies to address severe weather phenomena, the emergence of increasingly severe catastrophes has the capacity to overpower the current infrastructure and mechanisms established to minimise their effects. Additionally, it is generating effects that require quantification, analysis, and assessment in order to ensure appropriate adaptation. An essential adaptation strategy is adopting a proactive approach, which can only be achieved through the evaluation and assessment of climate change and variability, namely in the form of extreme rainfall storms.

Muri (2024) states that the primary cause of the rising global mean sea level since 1971 is the release of greenhouse gases by human activities, which leads to higher ocean and atmospheric temperatures. According to the Intergovernmental Panel on Climate Change (IPCC) in 2021, the average sea level worldwide had increased by 20 centimetres by 2018 compared to the level in 1901. Regional and local sea level change can significantly deviate from the worldwide average due to factors like land subsidence, which can contribute to a rise in relative sea level in those specific places. Moreover, climate change is accountable for the amplified monsoon precipitation, heightened frequency and intensity of rainfall patterns, and the repeated occurrence of pluvial floods in West Africa (IPCC, 2021). 

The flooding on Victoria Island, Lagos has detrimental effects on human health due to the pollution of water bodies and the rising occurrences of waterborne illnesses including as malaria, cholera, typhoid, yellow fever, diarrhoea, leptospirosis, and hepatitis A (Echendu, 2020; Olanrewaju et al., 2019). The ongoing overflow of raw sewage and garbage dumps in Lagos has resulted in the contamination of wells and boreholes used for domestic reasons. This further worsens the problem of limited availability to fresh water in the area (Olanrewaju et al., 2019; Atufu & Holt, 2018; Anabaraonye et al., 2024). Hence, the need for this inquiry arises.

Objectives of the study

The primary objective of this study is to critically assess the Impact of Climate Change on Flooding Patterns in Nigeria: A Case Study of flooding event in Victoria island, Lagos, in 2024. Specific objectives of this study are to:

To evaluate the level of flooding in Victoria island.

To evaluate the Impact of Climate Change on flooding pattern in Victoria island.

To assess the effectiveness of current flood management and mitigation measures in Victoria island.

To offer community-based adaptation strategies to enhance resilience and reduce vulnerability in Victoria island.

1.4 Research Questions

The following research questions will be answered in this study:

What is the level of flooding in Victoria island?

What is the Impact of Climate Change on flooding pattern in Victoria island?

How effective are the current flood management and mitigation measures in Victoria island?

What strategies can be implemented to enhance the adaptive capacity and resilience of communities in Victoria Island?

1.5 Research Hypotheses

The following research hypotheses will validate this study;

Ho: The level of flooding in Victoria island is low.

Ha: The level of flooding in Victoria island is high.

1.6 Significance of the study

The importance of investigating the influence of climate change on flooding patterns in Victoria Island, Lagos, in 2024 goes beyond its effects on the local area. This activity plays a role in advancing global climate research, providing valuable information for policy-making, and improving readiness for future climate-related difficulties in urban coastal regions. The study will provide a fundamental reference point for policymakers, residents of Victoria island and other areas susceptible to flooding, scholars, and students. 

Furthermore, climate change intensifies severe weather phenomena such as flooding. Comprehending the function of flooding in shaping patterns is crucial for evaluating environmental hazards and formulating approaches for sustainable development and environmental preservation.

Moreover, future scholars will utilise it as a thorough examination of the current body of scholarly literature. Consequently, prospective students with an inclination towards this field of study will have access to this work as a dependable and meticulously evaluated source of information.

1.7 Scope of the study

Broadly, this study focus is to critically assess the Impact of Climate Change on Flooding Patterns in Nigeria: A Case Study of flooding event in Nigeria, in 2024. Specifically, this study seeks to evaluate the level of flooding in Nigeria and evaluate the Impact of Climate Change on flooding pattern in Nigeria. 

Further, this study will focus on assessing the effectiveness of current flood management and mitigation measures in Nigeria and it also seeks to offer community-based adaptation strategies to enhance resilience and reduce vulnerability.

The study is carried out in Victoria island, Lagos.

1.8 Limitations of the study

As is common in all human endeavours, the researchers faced minor limitations when conducting the study. The main limitation was the lack of extensive literature on the subject, as there is limited data available for Impact of Climate Change on Flooding Patterns in Nigeria: A Case Study of flooding event in Victoria island, Lagos, in 2024. Consequently, a significant amount of time and effort was necessary to locate the appropriate materials, books, or information and to gather data. 

Additionally, this study is constrained by its small sample size and narrow geographical scope, focusing just on Victoria island, Lagos. Consequently, the results of this study are not applicable for generalization, thereby leaving room for further research. 

Additionally, the researcher's limitations were primarily due to financial constraints, as they are a student and do not have a source of income to sustain themselves. It was challenging to afford transportation expenses to and from the study location due to the high cost of transportation, which is influenced by inflation in Nigeria today.

Furthermore, the researcher faced a time constraint due to the need to do this research while also fulfilling the obligations of attending lectures and other educational activities.

1.9 Definition of terms

Flood: Flood is an overflow of water onto normally dry land. The inundation of a normally dry area caused by rising water in an existing waterway, such as a river, stream, or drainage ditch. Ponding of water at or near the point where the rain fell. Flooding is a longer term event than flash flooding: it may last days or weeks.

Flood pattern: Flood pattern" refers to the correlation and relationship between various parameters, such as rainfall and temperature, that contribute to the occurrence and severity of floods.

Urbanization: Urbanization is the process through which cities grow, and higher and higher percentages of the population come to live in the city.

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