The annual International Mother Earth Day was observed on April 22 to demonstrate and support for environmental protection.
Urban areas are now home to 50 per cent of the world’s population, but they account for 60-80 per cent of energy consumption and 75 per cent of carbon emissions. Rapid urbanisation is exerting pressure on fresh water supplies, sewage, the living environment and public health. In many cases, urbanisation is characterised by urban sprawl and haphazard development of periphery of the town which is not only socially divisive but increases energy demand, carbon emissions and puts pressure on ecosystems.
The Earth Day 2014 focussed on the global theme Green Cities. This would encourage people to create a sustainable, healthy environment by greening communities worldwide. As the urban population grows and the effects of climate change worsen, our city planning has to change.
Green vision for city planning includes three key elements: buildings, energy and transportation. A green city derives its energy from renewable sources like solar and wind and distributes it through efficient micro grids. A green city is made up of buildings that are energy-efficient, conserve water and reduce waste. Compact, relatively densely populated cities with mixed-use urban form are more resource-efficient than any other settlement pattern with similar levels of economic output. Urban infrastructure including streets, water and sewage systems come at considerably lower costs per unit as urban density rises.
Besides, a city that preserves and maximises its open spaces, natural landscapes and recreational opportunities is more healthy and resilient. Many cities have been designed with green space-oriented community development strategy at both national and local levels. Greenways may be designed as a planning strategy. These are networks of land containing linear element that are planned, designed and managed for multi purposes including ecological, recreational, cultural or other purposes compatible with the concept of sustainable land use.
Bhubaneswar was a city with pleasant climatic condition throughout the year. Since last decade, this city is experiencing high population growth, urbanisation and distinct weather condition. Earlier, it had a sound coverage of greenery, but now it has decreased substantially, leading to uncomfortable conditions. Modification of the land surface by urban development and reduction of open space is another reason for the unusual mercurial rise in Bhubaneswar in summer. Small water bodies and wetlands are increasingly being filled up by multistoried buildings.
The level of pollution has also increased due to the increasing traffic and decrease in foliage. The expansion of the city and lots of concrete structures are also the reason for its microclimatic change over the years. Bhubaneswar contained a 54-per cent forest area in 1930, which is now a mere 3 per cent, mostly shrubs only. As per the CDP-2008, the Bhubaneswar Development Plan Area (BDPA) contains only 19.07 per cent of forest area.
To develop green vision, green corridors can be designed properly in Bhubaneswar. The entire BDPA is gifted with tremendous natural resources in the form of rivers like Kuakhai, Bhargavi and Daya as well as areas with dense vegetation/forest such as Bharatpur forest area and Nandankanan Wildlife Sanctuary. In the CDP, the entire river belt zone has been proposed for recreational land use with green buffers running all along the river embankment, thereby forming a continuous ‘Green Corridor’ on the eastern side of the BDPA. Secondly, entire Bharatpur is a green zone with its forest area and the Nandankanan sanctuary placed sequentially along the main access. It is also forming the Green Corridor on the western side of the BDPA. These open areas must be developed as organised green and suitably landscaped. It is also advisable to have greening of the entire townships.
It is better to think of the open spaces of a city as a multifaceted matrix, performing a variety of functions and having a variety of uses. By this, cities can maintain green space within and throughout their urban and suburban centres, including trees and green space for recreation, cooling, stormwater management and simple aesthetic enhancement and livability. A number of cities are developing this idea of Green Corridor as a tool both for the protection of biodiversity and to provide a sense of continuity between town and the region.
Avenues of trees in the streets, public urban parks and conservation of green areas within private plots can all contribute to improving conditions in the urban area. Scattered green space within the compactly built up area may act as a continuous patch of green, widening at the edge of the city into the green belt and then into a rural landscape, establishing a coherent relationship between urban and rural areas. Such designs encourage healthy lifestyles with the ability to serve many daily needs by walking or cycling. This development patterns can also help keep a community economically vibrant.
People who live close to green space are more resistant to stress, have lower incidence of behavioural disorders, anxiety and depression and have a higher measure of confidence. Green space also stimulates social interactions between people.
As the concept of a green city is still new, their development faces many challenges. The large majority of green cities are still at the planning stage. Although there are many new ideas and agenda for green city planning, a few of them have been implemented to generate broad conclusions.
Many buildings are designed in the city without considering climatic conditions of the area. These buildings need air-conditioning to keep them cool. As an alternative, architects should keep climatic conditions in mind and design building that would cut down on energy consumption. More emphasis should be given on factors like ensuring maximum natural light and ventilation.
Green buildings have minimal adverse impacts on the natural environment and are designed to minimise the environmental impact of materials, construction and operation. They also seek to maximise opportunities for indoor environmental quality and performance, saving money, reducing waste, increasing worker productivity and creating healthier environment for people to live and work.
It has become paramount that an assembly of green buildings alone will not be the only deciding factor in green city developments. Many green innovations can be comprehensively integrated into statutory urban planning and development control systems, including planning standards and building regulations. Green building standards have been used in some cities as part of a move towards carbon neutrality. The bylaws and codes need to be revised to integrate aspects of green city and energy conservation building code. These regulations should include a combination of mandatory rules and voluntary guidelines such that minimum energy performance standards should be compulsory for all new buildings with flexibility in the ways to achieve the same.
With the rapid urbanisation and fast depletion of the earth’s resources, we need to rethink about planning our future cities. Planning, development and maintenance of urban green space is among the key elements of sustainable urban development. City planners must have a major role in designing green cities which would be more livable, sustainable and environment-friendly.
(Dr Mayarani Praharaj works in the Department of Architecture, College of Engineering and Technology, Bhubaneswar)