ASSESSMENT OF CLIMATE CHANGE AND VARIABILITY IN COASTAL REGION
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.