The Rio+20 Conference is taking place this week to mark the 20th anniversary of the 1992 Earth Summit. While the conference is not expected to produce legally binding international commitments, people do hope nations will agree to a set of shared principles and goals and initiate measurable and significant actions. One of the seven areas that Rio+20 will address is "sustainable cities", a logical choice, considering the global urbanization trend.
The pace of urbanization is especially fast in developing countries, seen most dramatically in China. When China opened its doors and started economic reform in 1979, less than 20% of the population lived in cities. Now, after over three decades of rapid economic development, 50% live in cities. Currently, China has about 660 cities and some 20,000 towns, all of which have been expanding in physical size and in population, but more rapidly in size. Many city officials are proud of their ultra-wide streets, over-sized squares, gigantic buildings, and massive gated residential housing communities, believing these to be the signs of modernization and success. Large Chinese cities used to be bike-able and walk-able, but have now sprawled and become heavily motorized.
Over the past two to three years, more than a hundred Chinese cities have each declared that they will build a low-carbon eco-city. While this trend is definitely positive and exciting, we note that most city governments do not yet recognize the strong link between car-centered urban sprawl and carbon emissions, therefore overlooking the important role of urban planning in low carbon development.
This attitude can be partially attributed to the fact that China is in the middle of industrialization. All cities either have or are rushing to develop a strong industrial sector, resulting in industries being the largest source of energy consumption in most Chinese cities. So most city officials give industrial energy efficiency the most attention. But in recent years carbon emissions from both buildings and vehicles have been rising quickly in Chinese cities.
Therefore, cities should plan and build their infrastructure according to smart growth principles which can greatly help in carbon emissions reduction in the long run by reducing material and energy consumption through more compact layouts and green buildings, and by reducing oil consumption through less frequent driving, as well as enhancing the quality of city life through more convenience and social interaction. NRDC has been a leader in promoting smart growth for urban development (see my colleague Kaid Benfied's extensive writing on this subject and my own related blog with respect to China here).
Walkability is arguably the most central concept when we talk about sustainable communities and the reduction of our carbon footprint. It is central because of its synergistic economic and social benefits, which includes accessibility, cost savings both to individuals and the public, increased efficiency of land use, increased social interaction and neighborhood vitality and safety, as well as benefits from improved public health.
Obviously, the quality of sidewalks greatly affects one's experience with walking. Let me use Beijing, where I am currently living, as an example for examination. In preparation for the Olympics, Beijing allocated funding for many arteries and areas most accessed by visitors, improving and beautifying sidewalks and creating bike lanes. These sidewalks were well thought out and developed, as seen by the colorful patterned cement tiles and yellow tactile guide paths in the picture:
However, this is not the case for many residential areas, working districts and collector streets. These walkways remain too narrow for comfortable travel and often have obstructions such as trees without tree grates, telephone poles, low wires, and parked bikes. This forces pedestrians to walk on the streets, disrupting traffic flow and creating hazardous environments where automobiles, bicycles and cars vie for pavement space.
Wide arteries encourage automobile drivers to speed, making for an even more dangerous environment for pedestrians. In residential areas and along collector arteries, a comfortable width for a sidewalk is at least 1.6 meters (6 feet). The sidewalk width in a downtown or "activity area" should be double this, approximately 3.65 meters (12 feet), at least half of which should be clear from obstructions (such as trees, telephone poles, bicycle racks, mailboxes, etc). This provides enough space for two pedestrians to walk side by side, or to pass each other comfortably. It also provides enough width for window shopping, street furniture (benches, lamps, etc) and places for people to stop without disrupting traffic flow.
China's design standards set minimum sidewalk width at 1.5 meters – the same minimum width regulated in Manhattan, and most of the United States. This is surprising as China's uran population density is generally much higher than U.S. cities. Aside from width regulation, sidewalks need to consider ramp grades, curb cuts and milling.
Beijing should be applauded for building many sidewalks with visually pleasing patterns, tactile guide paths, and shaded walkways provided by rows of trees. However, additional revisions to the design standards need to be enacted that are more pedestrian friendly.
NRDC's China Sustainable Cities team is developing a Walkability Index and using it to evaluate some Chinese cities. We think this index and rating will be a useful tool for raising the public and government’s awareness of this core concept of sustainable cities.
(Schuyler Viering, Kevin Hsu, Christopher Page, and Matthew Donovan have made contributions to this post.)
