To sprawl or get denser: the choices cities make affect their green spaces
As a strategy to attain sustainable urban development, planning policies in many European countries have advocated the concept of densification through development within the city in contrast to the urban sprawl that is prevalent in many modern cities. However, densification of cities implies compromising the existing green spaces within cities that provide important exosustem services within urban environments.
Temporal patterns of the urban spaces across 13 cities in England were examined by Dallimer and his colleagues in order to determine whether these changes in urban green cover have a potential association with policy changes at the national level. Between 1991-2006, the study documented a net increase in green spaces in all but one of the cities. However a closer look a the analysis suggested that much of the increase happened prior to 2001 which could be attributed to abandonment of industrial lands.
Differences in vegetation indices that captured changes in the annual pattern of greenness indicated that urban centres were losing green spaces due to densification post 2001. This coincided with the policy guidelines released in 2000 to limit urban expansion in the countryside. The rate of change in the number of dwellings outspaced the conversation of land use from green space to built-up area within this time.
The authors ascertain that land use changes in cities are extremely dynamic and respond largely to national level policy profiles. Rather than debating whether urban densification would lead to a more liveable urban environment and improve local services , trade-offs associated with the process of densification is required to maximise benefits associated with green spaces.
Policy changes invade on green spaces that are crucial that are crucial for human well-being and hence require necessary interventions to ensure equitable quality of life in urban environments.
Dallimer, M. 2011. Temporal changes in greenspace in a highly urbanized region. Biology Letters, 7:763-766.