By Roger K. Lewis
Saturday, September 27, 2008
How green can we get?
Architects and their clients increasingly pursue "green" ratings as a measure of the environmental sustainability of their buildings.
To do so, they employ multiple tactics: reusing aging structures, configuring new buildings compactly, installing effective insulation and energy-efficient mechanical systems, harvesting the sun's energy and maximizing use of daylight and natural ventilation, using recycled materials, recycling construction debris, conserving water and vegetating roofs.
Homeowners are also going for green by installing compact fluorescent light bulbs; replacing energy-wasting windows; upgrading heating and air conditioning equipment; buying hybrid vehicles; and walking, biking or riding transit instead of driving.
But can we go beyond this to make an entire city green? That means addressing the complex web of public infrastructure that affects sustainability -- transportation, utilities, open space.
In Washington last week, leaders from around the world focused on this question at the annual Capitals Alliance conference, titled "Greening the World's Capital Cities." Hosted by the National Capital Planning Commission in collaboration with the U.S. Commission of Fine Arts and the National Building Museum, the conference brought together representatives of capitals including Abu Dhabi, Brasilia, Canberra, Copenhagen, Helsinki, Moscow, Oslo, Ottawa and Stockholm.
For five days, attendees heard presentations, took excursions in the District and learned about greening efforts in other cities.
A primary lesson emerged: Sustainability has yet to become a public policy priority in the United States. Our cities have not adopted adequate sustainability goals and standards, nor have they eliminated such barriers as outdated zoning ordinances, building codes and regulatory practices.
There was consensus that regulatory reform and economic incentives, along with strong design guidelines, are absolutely necessary. Only then will costly yet essential environmental actions be vigorously pursued throughout private and public sectors, for cities as well as buildings.
Greening a city entails multiple strategies adapted to the city's conditions and needs:
· Plan and regulate future development -- smart growth -- so that land use and density are determined by and closely linked to existing and planned infrastructure, especially road and transit networks.
· Create and maintain a fine-grain pattern of streets to promote pedestrian and bicycle traffic as well as accommodate cars and surface transit. Set up traffic-management policies and technologies to ensure safety and mobility. For example, car access to severely congested parts of cities could be limited at designated times.
· Invest in state-of-the-art transit options -- bus and rail -- to complement road systems, including parking facilities that provide commuters access to transit stations.
· Line streets with trees that provide shade and reduce solar heat absorbed by paving and buildings. Properly planted areas along roads can also absorb and filter rain, thereby reducing and slowing runoff.
· Expand, preserve and maintain city-wide, interconnected networks of open space -- rivers and streams, steep valleys, wetlands, woodlands, parks and plazas. These networks can include parkways for cars and pathways for hikers and bikers.
· Upgrade and reconstruct rainwater collection systems to maximize use of open drainage swales and ground absorption, rather than underground piping. This recharges ground water while diminishing pollutants flowing into rivers, lakes and bays.
· Fully exploit renewable energy technology -- wind turbine farms and solar cell arrays -- to generate electricity on a metropolitan scale, especially as hybrid and electric vehicles proliferate.
"By the year 2050," the conference program noted, "three-fourths of the world's population is expected to live in cities. The consequences of this shift -- strained resources, traffic congestion, pollution -- will reduce our quality of life and contribute to global climate change. Clearly, the time has arrived for capital cities to lead the way to a more sustainable future."
Roger K. Lewis is a practicing architect and a professor emeritus of architecture at the University of Maryland.