Encroachment On Green Open Space, Its Health With Socio-Economic Implications Nigeria
The "United Nations World Urbanization Prospects", posits that the pace of city growth in recent time has been rapid, doubling in size every decade. It is estimated to add up to 2. 5 billion urban residents by 2050. This increase is to occur in developing countries like Asia and Africa with the greatest growth rate taking place in China and India. This unprecedented increase in urban population could not only pose challenges to infrastructure provision but also exert more pressure on urban green open space (GOS).
Seymour Gold 1973 and some scholars alerted the world of the importance loss of green space due to population increase, they emphasized on the need to maintain parks, gardens, playing fields and other green spaces. These agree with the principles of the Garden City as proposed by Ebenezer Howard, who integrated green space into settlements in response to overcrowding and unhygienic living conditions in cities in the U. K after the Industrial Revolution. Recent challenges came up as to really constitute a GOS which made Travdou (2007) to described urban open spaces as natural and cultural resources, synonymous with neither "unused Land" nor park or recreational areas; or land or water area with its surface open to the sky consciously acquired or publicly regulated to serve conservation and urban shaping function as well as provide recreational opportunities. These are to include areas outside of city boundaries such as state and national parks.
Taylor and Hochuli (2017) recently gave an all-encompassing definition of green open space, as constituting vegetated urban land that is public or semi-private such as parks, sports fields, cemeteries, vegetated areas of street and road corridors, natural and built corridors adjacent to waterways and wetlands and external areas to public buildings. This definition has been adopted in this paper as adopted by the Scottish Natural Heritage and Medicine, 2008, according to Boulton, Dedekorkut-Howes, and Byrne (2018). The population of cities is initially concentrated at the core with limited land resource, equitable and sustainable development of urban land and urban space to cater the needs of this growing urban population which is a global challenge. This has forced the development to the periphery leading to encroach on green open spaces. Hence the periphery in now area of a rush due to the availability of cheap land. This quest for land for development has led to sprawling development on available space away from the city core. This “Urban Sprawl, ” is being identified as a significant aspect of urbanization and encroachment on GOS. This is in contrast to the key tenets of sustainable development and smart growth which promotes densification and equity in land development.
Encroachment and conversions thus, have become a common phenomenon in various parts of the world, which makes sustainable management an issue of concern due to its implication on healthy living, break in a socio-spatial continuum and loss of urban leisure culture, loss of undeveloped land as it is converted to housing, commercial, warehousing, and other land uses. The GOS has been known to help improve health condition by facilitating psychomotor activities and cognitive functions (commonly assessed using measures of attention, systolic and diastolic blood). The green open space in nature functions to modify the physical environment, thereby reducing health risks for people; this is known as the biophysical ecosystem service. Increase contact with the GOS, can also increase a sense of community, public safety, and also help to reduce socio-economic inequalities. GOS is known for its potential to gift and assists in addressing many of the aforementioned health issues. Researches have shown linkages between exposure to GOS and physical, psychological, and social well-being. It has been also found that increased green vegetation cover is an important strategy for reducing the effect of urban heat island as it provides shade which reduces evapotranspiration and heat reflection. Vegetation can filter pollutants from the air and buffer the urban heat island effect, potentially reducing the prevalence of respiratory infections or heat-related illnesses.
Hartig et al. 2003 and Fuller et al. 2007, found lower rates of mortality from cardiovascular disease and all-cause mortality in neighborhoods with higher levels of green space. Ewing, Hamidi, Grace, et al. 's (2016) research provides evidence of the negative effects of urban sprawl on upward mobility. Lee et al. (2018) find this consistent with the expectations that lower levels of sprawl are averagely associated with lower levels of income inequality and lower levels of sprawl correspond to higher levels of financial well-being. Researches like the spatial mismatch caused by urban sprawl are becoming increasingly available to show the effects of sprawl.
Many countries have applied various management strategies to curb these problems. For example in China, the major strategy employed is to provide the public with environmental information. Particularly, this was found to have served as an invaluable tool for the city of Yangzhou by facilitating interaction with citizens through the city's Eco Centre( Johnson 2001), while in Thailand (Bangkok) the city management instrument was made to link with city's agenda of development to serve as a driving force for physical development while the Eco-management audit scheme is the European Union's voluntary instrument which acknowledges organizations that improve their environmental performance on a continuous basis.
In Durban (South Africa) community-owned initiatives were applied to achieve a clean and livable environment. The Cities Alliance (2007) reported that in São Paulo (Brazil) enlightenment conferences were organized for stakeholders. Sydney Metropolitan Strategy as a Plan for Sydney's Future supports continuing economic growth while balancing social and environmental impacts. It is based on anticipated population, economic and demographic trends. The Plan has been developed with five aims - Enhance Livability, Strengthen Economic Competitiveness, Ensure Fairness, Protect the Environment.
In Nigeria and indeed Akure not much has been done in explaining to the stakeholders the implication of this trend of development, there is a disconnect in dealing with these issues in the city between stakeholders and the city managers. Literature has been found to be more oriented toward the costs of sprawl than effects on GOS and sustainable health issues. While the literature on sprawl and its impacts are well-established, there is little understanding of how urban sprawl might have effect on socio-economic activities and health. Akure being an emerging urban area is adjudged one of the cities suitable for the study considering its rapid rate of population increase. Therefore, with the view of the need to avoid negative dynamism of loss of green open green spaces occasioned by poor management, in comparison to understanding the myriad ways in which urban expansion spatial and sustainable development relate to each other.
