Cities and Biodiversity Outlook
Maintaining functioning urban ecosystems can significantly improve human health and well-being

With proper planning and resources, mutual benefits for human and environmental health can be achieved and several urban health concerns can be addressed

The health benefits that we derive from direct contact with ecosystems range from improving immune function, mood, and concentration to reducing stress and enhancing the benefits of physical exercise. Ecosystems also indirectly support human well-being by providing, for example, air and water purification, pest control, and climate regulation.

Developing urban spaces that improve air quality, promote active living, and facilitate good nutrition and dietary diversity can enhance human health and biodiversity. Improved public transport and bicycle/pedestrian pathways can lead to increased physical activity and reduced greenhouse gas emissions.

Urban agriculture can promote dietary diversity and improve nutrition and food security, while also supporting agricultural species conservation and limiting the urban food-supply "footprint." Urban agriculture can lower the pressure for food supplies from surrounding rural regions, and this in turn can conserve natural ecosystems and support their ability to regulate wildlife-related infectious diseases.

Understanding the complex interactions between urban populations and infectious diseases such as cholera, dysentery and malaria is paramount, particularly since approximately 1 billion people currently live in squalid, slumlike conditions. Such diseases can often be curbed with a combination of measures, including adequate sanitation and sewage systems, as well as the conservation and restoration of local wetlands.

Another health challenge that cities are well placed to consider is that of mental illness. This is often associated with rapid social change, stressful work and living conditions, unhealthy lifestyles, physical illness, and more recently, changes in the urban environment. Making biodiversity a priority for development policies can provide mental health benefits such as reduced stress, better resilience in times of adversity, improved mental concentration, and enhanced recovery time from sickness and injury.

Curitiba's Innovative Approach to Waste Management
The population of Curitiba, Brazil, exploded from 120,000 to more than 1.7 million between 1942 and 2012, challenging the city to provide food, water, and sanitation services to its residents. By the early 1970s, poverty, waste, and disease were rampant in the city's slums. Today, with 46 protected areas and 64.5 square meters per inhabitant, Curitiba is known as "Brazil's green capital" and is hailed as a prime example of a green economy in a developing country. Among its innovations is the Green Exchange Programme, which encourages slum dwellers to clean up their surroundings and improves public health by offering fresh fruit and vegetables in exchange for garbage and waste brought to neighborhood centers. As of 2012, Curitiba has 96 exchange sites. Each month more than 6,500 people are exchanging an average of 255,416 kilos of collected garbage for 92,352 kilos of fruits and vegetables.

Greenery in Slums: A Valuable Source of Traditional Medicine
In many slums, the presence of trees and plants that heal is extremely crucial, as traditional medicine is typically the most economical, trusted, and readily available form of health care in such settlements. In Bangalore, one of India's fastest growing cities, an estimated 30-40 percent of the population lives in 550-plus slums. Surveyed slums in Bangalore have an average of 11 trees per hectare, versus 28 per hectare in other residential areas. The species that dominate are of high medicinal and nutritional value and are sources of primary health care. The trees also offer many socio-cultural services. Daily chores such as cooking and washing are carried out under tree cover. Trees act as pillars of support in such settlements—figuratively and literally by bearing tents, clotheslines, wires, and so on. The variety of roles that plants play in slums is critical to people's health and well-being.

Healthy Parks, Healthy People
Parks Victoria, a park management agency of the State Government of Victoria, Australia, launched the "Healthy Parks, Healthy People" (HPHP) approach in 2000. The goal was to emphasize the value of visiting parks and natural open spaces for the benefits they provide as healthy places for body, mind, and soul. Similar approaches have now developed around the world, including in Canada, the UK, and the USA. The Melbourne initiative that emerged from the first International HPHP Congress declared that parks are "integral to healthy people and a healthy environment" and that "human health depends on healthy ecosystems." The Congress was also the springboard to a partnership with a national health insurance provider, which is now funding public preventative health activities and establishing a network of health professionals to encourage people to increase their physical activity by engaging in activities in parks.

Healthy Parks, Healthy People - Nepal
The Healthy Parks, Healthy People concept is also being adapted to developing countries, beginning with HPHP Nepal, a partnership involving the International Union for Conservation of Nature, Parks Victoria, and the Nepalese government. A 2010 workshop in Kathmandu highlighted that HPHP and resulting lessons learned could indeed be applied in countries with different socioeconomic contexts. As Dr. Chhatra Amatya, chairman of Chhahari Nepal for Mental Health, explained, "HPHP is all the more needed in a country like Nepal. Our children do not have space to play a game in a city."

More Trees, Less Childhood Asthma: New York City
Rates of childhood asthma in the USA increased by 50 percent between 1980 and 2000, with the highest rates reported in poor urban communities. In New York City, where asthma is the leading cause of hospitalization among children under age 15, researchers at Columbia University studied the correlation between numbers of trees on residential streets and incidences of childhood asthma. They found that as the number of trees rose, the prevalence of childhood asthma tended to fall, even after data were adjusted for sociodemographics, population density, and proximity to pollution sources. How might trees reduce the risk for asthma? One explanation is that they help remove pollutants from the air. Another is that trees may be more abundant in neighborhoods that are well maintained in other ways, leading to lower exposure to allergens that trigger asthma. Yet another is that leafy neighborhoods encourage children to play outdoors, where they are exposed to microorganisms that help their immune systems develop properly. Further studies will provide a clearer picture of whether street trees really do make for healthier children: New York City is currently in the midst of planting a million new trees by 2017.

The Many Benefits of Urban and Peri-Urban Agriculture
Raising local crops and livestock can increase knowledge of and interest in the biophysical and food-growing processes, empower citizens to influence sources of food production, strengthen links to local food systems, and encourage healthier lifestyle choices. Greater food self-reliance, cheaper food prices, greater accessibility to fresh and nutritious products, and poverty alleviation are all key benefits that can arise from urban agriculture with sound decision-making and planning of the cities' ecosystems. The advantages of urban and peri-urban agriculture have been noted by the UN Food and Agriculture Organization (FAO) and by the World Health Organization's Healthy Cities Programme, which appeals to local governments around the world to include urban and peri-urban agriculture in their urban plans.

From Open Dump to Greenery: Mumbai's Gorai Dump Closure Project
The city of Mumbai, India, generates about 6,500 tons per day of municipal solid waste and about 2,400 tons per day of construction waste. For almost 40 years, all of that waste went to Gorai Dump—a 20-hectare open site in Mumbai's western suburbs. Situated next to a creek and close to residential areas, the dump had caused significant environmental damage and long been known as one of the unhealthiest places in Mumbai. Closure of the site in 2009 involved leveling and reforming the heaps of garbage (their average height was 26 meters), covering them with impermeable surfaces, and converting them into a high-quality green area. The next step will be installing a power plant at the site that will run on methane gas from the decomposing garbage—thereby producing electricity as well as reducing green house gas emissions. The project has already yielded many public-health and lifestyle benefits that have transformed the lives of local residents. They have a beautiful new green space to enjoy, air and water quality have improved, breeding flies and rodents have been eliminated, and property values in the area have increased fivefold.

Image source: Iwan Bann

Bogota

Figure 1: Bogota
In Bogota, Colombia, physical activity has increased significantly and greenhouse gases have been curtailed by closing 97 kilometers of a major road to traffic on Sundays and during holidays, improving the bus transit system, using cleaner buses, and creating a 334-kilometer bicycle path around the city.
Photo: Digital Globe / Google Earth

Curitiba

Figure 2: Curitiba
The population of Curitiba, Brazil, exploded from 120,000 to more than 1.7 million between 1942 and 2012, challenging the city to provide food, water, and sanitation services to its residents. By the early 1970s, poverty, waste, and disease were rampant in the city's slums. Today, with 46 protected areas and 64.5 square meters per inhabitant, Curitiba is known as "Brazil's green capital" and is hailed as a prime example of a green economy in a developing country. Among its innovations is the Green Exchange Programme, which encourages slum dwellers to clean up their surroundings and improves public health by offering fresh fruit and vegetables in exchange for garbage and waste brought to neighborhood centers. As of 2012, Curitiba has 96 exchange sites. Each month more than 6,500 people are exchanging an average of 255,416 kilos of collected garbage for 92,352 kilos of fruits and vegetables.
Photo: Digital Globe / Google Earth

New York City Temperature and Vegetation

Figure 3: New York City Temperature and Vegetation
Urban heat island in Ney York City.
Source: NASA Earth Observatory