Ecosystem Loss: The True Cost of Building an Unsustainable Mega City

Author ~ Ebuka Onunaiwu

As human population and activities increase globally, the need for space also increases as most human population dwell on land and majority of our activities are carried out on land, too.

Urbanisation, which is the conversion of land to uses associated with growing population and economy, has been recognised as having a world-wide trend. More than 50% of the world’s population currently reside in cities and urban settlements. Urban populations and other ecosystems are said to have been engaged in a turbulent, somewhat symbiotic marriage since the dawn of civilisation. Although essential for human well-being, some ecosystems have been progressively lost and degraded by human activities since then.

Rapid urbanisation and urban areas are known to generate negative impacts on the environment as they lead to changes in landscape patterns, ecosystem functions and their capacity to perform functions in support of human populations. This is especially so when rapid or unplanned growth occur in areas of highly vulnerable systems such as coastal areas and wetlands. The conversion of large tracts of other ecosystems into built-up areas result in increased biodiversity loss, flooding and altered aquifer recharge amongst others. Quantifying such changes in the landscape patterns can be useful in tracking the capacity of natural ecosystems to render services in support of human systems say Flores, Olivas and Chavez in their 2008 paper ‘Land Cover Change and Landscape Dynamics in the Urbanizing Area of a Mexican Border City’. It is also necessary as inputs to environmental resource planning, environmental management and sustainable development.

In developed and developing countries, wetlands, the coastal zone and water bodies are likely to undergo the most profound change in the near future. More than 60 percent of the world’s population live within 60 kilometres of the coast. By the turn of the century two-thirds of the population (3.7billion) in developing countries would have occupied the coast observed Niya, Alesheikh, Soltanpor and Kheirkhahzarkesh in their 2013 GIS Case S Shoreline Change Mapping Using Remote Sensing and GIS Case Study: Bushehr Province

Over the years, Lagos State has grown from a settlement to a huge metropolis and now to a megacity.  In essence, the population which was negligible in its early years has risen from about 5.7million in 1991 to over 20million currently.

Metropolitan Lagos, the current economic capital of Nigeria, and some of its suburbs have developed on coastal environment characterised by low-lying tidal flats, estuaries, wetlands and sandy barrier beaches, some of which were reclaimed unsystematically for development. Spurred by demand for land for rapid urbanisation, this unplanned and extensive reclamation of wetlands, sand filling of lagoon shores, excessive dredging, encroachment on natural drainage channels and unrestrained deforestation have all been significant features of metro Lagos. During this time, several other ecosystems especially coastal areas have been converted to high density unplanned residential housing areas, and the precise nature of these changes is largely unknown and unreported.

According to Nodza, Onuminya, T.O. and Ogundipe 2014 study of tree species growing on the Akoka Campus of the University of Lagos, Nigeria, urbanization has led to the marking of some trees as high-risk species. From the result of their findings, they observed that due to the high rate of degradation on the remnant flora species, resulting from habitat conversion into residential areas (urban centres), indiscriminate degradation and reclamation of mangrove for development of several infrastructural facilities in order to satisfy insatiable human wants, these species now require high conservation priorities for sustainability.

Consequently, if we do not attempt to carefully institute environmental management and planning practices, severe conflicts over ecosystems space and resource utilisation would arise, and the degradation of natural resources will close development options. It is, therefore, of rising need that proper steps are carried out to mitigate the resultant effect of urbanisation, as this will help in the conservation of other important ecosystems. Also, such proactive steps will equip both private and public town planners in building sustainable urban cities, as well as prepare them for events such as climate change.



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