SIEMENS

At first glance, the capital of Denmark — Copenhagen — and the South African city of Durban seem to have little in common. But there is a connection between them, as both cities want to become CO₂-neutral. Copenhagen has set itself a target date of 2025 for this; Durban is aiming for 2050. Both cities now understand that environmental protection is no longer a luxury, but rather a necessity in rapidly growing cities around the world. Around half the world’s population now lives in cities, and that percentage is expected to increase to two thirds by 2050, when as many people will be living in cities as now populate the entire Earth.
More and more people will need water and electricity, the amount of waste will increase, traffic will become more congested, and sewage systems will be stretched to the limits of their capacity. All of this will negatively impact the environment and the economies of urban centers — as well as the health of their residents. Addressing these problems requires a fundamental understanding of where the challenges lie and how different cities are dealing with them. This is exactly what the Green City Index — a series of research projects carried out by Siemens and the Economist Intelligence Unit (EIU) — has been trying to achieve for three years now. The index examines the entire range of environmental sustainability issues, including CO₂ emissions, energy, land use, buildings, transport, water and wastewater, waste management, air quality, and environmental policy. Green City Index studies have been published for Europe, Latin America, Asia, the U.S., Canada, Germany, and Africa — and Pictures of the Future has presented the most important results in past issues. A new study for Australia and New Zealand is now being developed.

The world’s cities are marked by different conditions. For example, Asian cities have twice as many people on average as European urban centers. Income levels also vary sharply. Whereas the U.S. and Canada have a per capita gross domestic product (GDP) of US$46,000, residents of cities in Latin America live on an average income of $11,100. However, comparisons of the city indices also show that many metropolitan areas have already improved their environmental performance by making infrastructure more efficient or implementing ambitious policies — and their achievements can serve as an example for other cities around the world. Still, one must keep in mind that each City Index takes into account specific aspects of the region in question, which means direct global comparisons can be made for only a few parameters.

• ● High population density makes it easier to build infrastructures such as public transport.
• ● The most densely populated cities are in Asia, where average density is around twice as high as in cities located in the other regions studied. Mumbai, for example, has 27,000 people per square kilometer — the highest level among all the cities studied.
• ● Urban sprawl is a problem that is especially widespread in North American cities.

• ● Latin American cities have many parks and recreational areas. The region has around 255 m2 of green space per person; the figure for Asia is only 39 m2.
• ● New York and Singapore are role models for spatial planning, as both have been able to combine extensive green spaces with high population density.

• ● Cities in Canada and the U.S. generate more per capita CO₂ emissions on average than European and Asian cities combined.
• ● The best city in the industrialized world in this category is Oslo, which has emissions of 2.2 tons per person.

• ● Europeans produce the most waste. Only ten percent of the European cities that were studied generated less than 400 kg of waste per person each year.
• ● The best city in the industrialized world is Yokohama (300 kg per person and year).
• ● The best result in the global comparison was achieved by Delhi, with only 147 kg of waste per person each year on average.

• ● With a recycling rate of 81 percent, the city of Leipzig in Germany is the world recycling champion, although North American cities boast the best overall performance in this category.
• ● San Francisco recycles 77 percent of its waste; Los Angeles has a recycling rate of 62 percent

• ● Urban residents in Europe mainly use public transport, bicycles, or their legs to get to work, with Stockholm taking the lead here (93 percent).
• ● The situation is different in North America, where 87 percent of city dwellers drive to work. New York is a positive exception, as 37 percent of its residents use public transport.

• ● Leaky water pipes are a major problem in developing countries and emerging markets especially. Rio de Janeiro loses 58 percent of its water through leaks.
• ● Bad pipes aren’t as much of a problem in U.S. and Canadian cities, however, as 15 of the 27 cities studied there lose less than ten percent of their water through leaks.
• ● Chicago, Tokyo, Amsterdam, and Berlin had the best results in the global comparison for this category, with each losing only around three percent of its water.

• ● Africa consumes the least amount of water, because many people there have only very limited access to drinking water.
• ● Tallinn (Estonia) and Amsterdam consume the least water in the developed world — only around 140 liters per person each day.
• ● However, three cities in the U.S. and Canada consume more than 800 liters of water per person per day.