Towards a green economy

foster a sense of community (Frumkin 2003; Litman 2006). Such changes are often designed to counteract instances of community severance, as identified by Bradbury et al. (2007):

■ Physical barriers whereby either spatial structures themselves prohibit interaction or certain activities cause disruption, as in the case of road traffic;

■ Psychological barriers that are related to the

perception of certain areas determined by traffic noise and pollution or perceived danger; and

■ Long-term social barriers where residents change behaviour following initial disruptions and create a more sustained form of being disconnected from certain people and areas close-by. Putnam’s research implies that ten minutes avoided in commuting increases time spent on community activities by 10 per cent (Putnam 2000).

Kuo et al. (1998) observed that the more trees and greenery form part of inner-city public spaces, the more these spaces are used by residents. The study also found that, compared with residents living near barren spaces, those closer to greenery enjoy more social activities, have more visitors, know more of their neighbours, and have stronger feelings of belonging. Wells and Evans (2003) found that children with nature near their homes are more resistant to stress; have lower incidence of behavioural disorders, anxiety, and depression; and have a higher measure of self-worth (Grahn et al. 1997; Fjortoft and Sageie 2000). Green space also stimulates social interaction between children (Moore 1986; Bixler et al. 2002).

A further dimension in the quality of life surrounds road safety. Road traffic accidents are the leading cause of death among young people between 15 and 19 years, according to a report published by the WHO in 2007 (Toroyan and Peden 2007; see also Transport Chapter). Road traffic collisions cost an estimated US$ 518 billion globally in material, health and other expenditure. For many low- and middle-income countries, the cost of road crashes represents between 1-1.5 per cent of GNP and in some cases exceeds the total amount the countries

receive in international development aid

(Peden et al. 2004). Mohan (2002) showed that this is, in fact, underestimated and evaluated that these costs represent 3.2 per cent of India’s GDP.

Some of the most effective strategies to improve pedestrian and cyclist safety include dedicated facilities and motorised vehicle speed controls. An average increase in speed of 1 km/h leads to a 5 per cent higher risk of serious or fatal injury (Finch et al. 1994; Taylor et al. 2000). Dedicated lanes for buses, bicycles and pedestrians, especially along arterial roads should also

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be a priority. Evidence from the Netherlands, Bogotá and Denmark shows that restricting the space available to cars, limiting their speed and providing safe facilities for pedestrians and cyclists result in the adoption of green transport modes.

Other major attributes of green cities are also considered part of the quality of life, such as walkability, access to green spaces, cycling infrastructure and recreational facilities

(HM Government, Communities and Local

Government 2009). In developing countries, this may partly explain the relationship between green cities and cities with a high quality of life. Among the top 20

“quality of living cities” identified by Mercer in 2009, at least half have particularly strong green credentials (Table 5). The top five includes best-practice green cities such as Vienna, Zurich and Vancouver. In Zurich, the city’s focus on public transport has been an important contribution to its favourable ranking in the Mercer survey (Ott 2002). Similarly, the integration of green space and natural elements within the city significantly enhance the quality of living.

At least in developed countries, a city’s overall quality of life (or quality of place), may be linked to economic advantages, mainly as a result of greater attractiveness to skilled workers and high paying firms (HM Government, Communities and Local Government 2009; Lee 2005). Evaluation of the largest companies (more than 500 employees) in the European Union suggests that about 10 per cent of these firms consider quality of life as one of the top three attributes determining location decisions (Healey and Baker 1993 in Rogerson 1999). These decisions, it is argued, are increasingly based on so-called city “lifestyle amenities” which attract highly- skilled, mobile workers with their general flexibility in choosing living and working locations (Hasan 2008).

3.3 Environmental and health benefits

Reducing pollution and improving public health Air pollution in cities remains a major public health burden, particularly in the developing world. In extreme cases such as Dakar, pollution-related health costs are above 5 per cent of GDP, while a range between 2 and 3 per cent is observable for several mega cities in Latin America and Asia (World Bank 2003). In urban areas globally, around 800,000 deaths per year are caused by air pollution (Dora 2007).

Many cities have already taken decisive action and significantly improved the situation. Outside Europe and the USA, cities with PM 10 levels of 20 mg/m3

have

a mortality rate almost 10 per cent lower than those with levels of 150 mg/m3

(Dora 2007). Urban greenery provides a unique opportunity to improve air quality. In