Green urbanism has been defined as the practice of creating communities beneficial to human and the environment. According to Timothy Beatley, it is an attempt to shape more sustainable places, communities and lifestyles, and consume less of the world's resources. Green urbanism is interdisciplinary, combining the collaboration of landscape architects, engineers, urban planners, ecologists, transport planners, physicists, psychologists, sociologists, economists and other specialists in addition to architects and urban designers.
Urbanisation and environmental consequences has always moved hand in hand. Odum in 1989 has called cities as 'parasites' on natural and domesticated environment, since it makes no food, cleans no air and cleans only a little amount of water for reuse and Mayur (1990) has argued that such disharmony may result in environmentally catastrophic events (cited in Leitmann, 1999). Leitmann mentioned such critical urban environmental problems as the 'brown agenda' which deals with both environmental health and industrialisation. He further pointed out that throughout the 19th century; developing countries were more concerned of the public health impacts of poor sanitation and pollution. Moreover, he figured out the links between cities and ecosystems into three phases. Early Urbanisation phase, starting from 3000 BCE to 1800 CE, was of more productive agricultural techniques yielding a surplus that was able to support non-agricultural concentrations of people. In second phase, Urban Industrialisation (1800 CE - 1950 CE), energy consumption, particularly fossil fuels, was increased rapidly with mechanisation of production. Since the 1950s the city/environment relationship has entered into third phase, Global Interdependence, with rapid population growth and globalisation of economy. Cities became the nodal points for large and globally interconnected flows of resources, wastes, and labour. Also, environmental problems are local, regional and global in scale, with cities increasingly contributing to global environmental damage.
Rydin (2010) accused the cities as both villains and victims of climate change pattern. Climate change affecting urban sustainability in regards to temperature increase which may exacerbate urban heat island (UHI) effect and rainfall patterns (Rydin, 2010). Some other cities may also go through environmental catastrophes, like cyclone and storm, coastal erosion, sea-level rise, ground instability and changes in biodiversity. The whole scenario called for an urgent need to focus on rebuilding the urban ecosystem with given emphasis on the human settlements.
A glimpse on the history of green urbanism of US as found in Karlenzig, et al. 'How Green is Your City' book (2007, 06-07). The concept had a gradual start in the late 1800s, when some large cities of United States (US) started using advanced drinking water, sewage and sanitary systems. Consecutively, public parks and open spaces were implemented in New York City. At the end of the World War II, the US government offered its citizens affordable housing in easy loan to boost up city population and also introduced a new federal Interstate System, combined with a rise of automobile ownership, gave away to a novel way of life called 'Suburbia'. Meanwhile, in the 1950s the inhabitants of other industrial cities, including Chicago, Detroit, St. Louis, Cleveland and Philadelphia, had already experienced greener suburban pastures. But all those green trees died because of old age or pollution, and were not replaced. The first book describing the comprehensive rebuilding of cities toward balance with nature is "Los Angeles: a History of the Future" (1982) by Paul Glover (activist). After a decade of the 'Urban Renaissance', the term used by Richard Rogers, came into light in 1990. Europe was never far behind to endorse urban sustainability. 'The Green Paper on the Urban Development' published in 1990 has been considered as a 'milestone' document in promoting sustainable city projects as a solution to global environmental role (Beatley, 2000). Lehmann (2010) mentioned that since then cities have engaged themselves in a global-scale competition with each other in three distinct areas. These are, firstly, to be regarded as an attractive, creative place and a cultural hub to attract highly skilled workers and Melbourne, Australia was strong competition with arts, museum and university; secondly, to get recognition as a place for secure investment, mention worthy, Dubai, Shanghai, and Singapore have topped in attracting and facilitating global investment capital; and thirdly, to become a leader of green vision for the future by technological advancement and offering environmentally sound lifestyles and also providing green jobs and Hannover, and Copenhagen did well in this field.
After the earth Summit, 1992, different terms, including, sustaining cities,sustainable cities (Beatley, 2000), sustainable urbanism (Farr, 2008), green city (Karlenzig, 2007), eco-towns, eco districts and eco-cities (Lehmann, 2010), have tried to reduce environmental impacts on the cities and to achieve sustainable development and thus to live more peacefully, there. Both the green and sustainable cities present fundamental opportunities to apply new technologies for example, public transport, district heating, green building and green design and also bring major lifestyle changes such as, walking, bicycling, and reduce energy consumption. The major agenda of the all kinds of the above mentioned cities are tackling global climate change, biodiversity loss, and also lift themselves as 'hosts' of all environmental challenges.
It has been argued that the focus of these theories are mainly on adjusting the relationship between the city and nature and also creating new cities other than renovating existing cities. To address the gap, Timothy Beatley and Steffen Lehmann used the 'green urbanism' theory that aims to transform existing cities from fragmentation to compaction.
Beatley remarked that the vision of green urbanism includes programs, policies and creative design ideas for urban renewal and environment sustainability. Lehmann added the phrase also provides a proactive vision of what might be our zero-carbon, fossil fuel free future: overlapping mixed-use activities, living and working building typologies explored on the urban scale, infrastructures systems for renewable energies, public transport and individual energy-efficient building designs. According to Beatley, cities that exemplify green urbanism are:
It has been noted that urbanisation is widely understood to be a key driver of carbon emissions, resource depletion and environmental degradation. The principles of green urbanism are based on the triple-zero frameworks. These are zero fossil-fuel energy use, zero waste and zero emissions especially aimed for low-to-no-carbon emissions. Lehmann(2010) tries to put up a strategic case study of green urbanism with the seaport city of Newcastle, New South Wales, Australia. According to him, there are 15 such principles of green urbanism those are practical and holistic and integrated framework, including all the aspects needed to achieve sustainable development and encouraging best practice models, as follows:
Many cities now have Sustainable Action Plans which is a roadmap towards sustainability. Green Urbanism has grown from textbook methodologies to living action plans that survive beyond the election cycles of city mayors and counsellors.
Green Urbanism poses the demand for an applicable method in planning and management of a city. Wybe Kuitert proposed analyzing the city as a landscape system to reach at a more comprehensive approach towards this end. The urban landscape connects the cultural components, like identity and history with the natural physics of a city, like its geography, water and natural ecology. As such it poses a vision that can be applied to any city, rich or poor. Discerning the potential quality of wild nature in the city is a first step to see what nature can give, if we only have an open eye for it. It is discovered through the potential vegetation map for the city. There is a lot of Conferences talking about this Field as 'Green Urbanism' which will be held in Italy from 12-14 October 2016.