We recycle cans and bottles, why not buildings?

Since the first curbside recycling program was initiated in 1987, Seattleites have become accustomed to recycling paper, glass, metals and yard waste. Many see it as their civic duty and a way to help the environment.

Still, the city of Seattle sends by truck and train more than 50 percent — 440,000 tons per year — of its municipal waste to landfills, much of it to Bend, Ore. A large percentage of municipal landfill waste is from construction and demolition debris, estimated to be between 20 and 30 percent nationally.

Construction and demolition waste is produced from new construction and renovation of buildings, and by the demolition of existing buildings. Such waste is an enormous environmental problem because of the sheer volume of discarded construction-related refuge dumped into landfills.

We recycle cans, bottles and even plastic bags, so why not reuse older buildings? There are many good reasons to do so, and opportunities and benefits abound to reduce such waste.

First, it's very costly and energy consumptive: Municipal waste that must be loaded, hauled, transferred from trucks to trains, processed and dumped into landfills costs between $50 and $75 per ton.

Second, it pollutes: Fuel used in the handling and disposal contributes significantly to environmental impacts and carbon emissions. Landfills are filling up, and the sites themselves pose environmental hazards from loss of natural-resource lands, leaching of toxic chemicals and release of methane gas.

Third, it's wasteful: Most construction debris — such as land clearing, wood, metal, glass, asphalt and concrete rubble — is fully reusable at lower cost than the production of new materials. Upstream, reducing construction and demolition waste reduces the need for the extraction and processing of raw materials, product manufacture and eventual disposal.

And finally, the preservation and adaptive reuse of older buildings — especially historic landmarks — as compared with new construction is considered to be one of the most sustainable "green building" practices achievable.

Climate-protection strategies must address the issue. In the United States, building construction and operations account for 48 percent of greenhouse-gas emissions. The U.S. Environmental Protection Agency sees enormous benefits from preventing construction and demolition waste, and has made it a top policy priority over land-filling, incineration and even recycling.

In Seattle, nearly 700 buildings were torn down last year to make way for new buildings. This is an enormous lost source of renewable, embodied energy. A recent study by the Brookings Institution projects that by the year 2030, we will have demolished and replaced 82 billion square feet of our existing building stock, or nearly one-third of our 300 billion square feet of space in the U.S. today.

How many bottles and metal cans would we have to save and recycle to match an equivalent amount of construction and demolition waste and embodied energy — the amount of energy originally embedded in the materials and expended through extraction, processing and construction? There is no reason why durable buildings of all types and ages cannot be adaptively reused, retrofitted, or at least deconstructed and recycled, rather than be demolished and hauled off to landfills.

While preservation laws help protect our valued historic landmarks, incentives and possibly new regulations are needed to address waste of building stock. For example, Portland, Ore., mandates that all building projects valued at over $50,000 separate on site and recycle all nontoxic construction materials. New York City provides tax incentives, electric rebates and employs rezone strategies to encourage reuse and conversion of commercial buildings to residential.

King County's GreenTools recycling program emphasizes education and outreach to contractors and suburban cities on the environmental and economic benefits of reuse and recycling. Another approach would be to impose a federal carbon tax on the demolition of existing buildings, calculated on the embodied energy wasted in disposing of the structure.

The bottom line: Landfills should no longer be an option for used but otherwise clean and durable building materials. Policymakers, preservationists and architects need to push green building practices into the 21st century by promoting the environmental, economic and community benefits of building reuse and recycling. State and local governments should establish working guidelines, programs and incentives to promote the reuse, retrofit and reinvestment of older buildings.

The energy invested in the existing built environment must be seen as a tangible resource of economic, environmental and cultural value, not to be wasted. In this way, preservation and reuse can be our "greenest" tools of sustainability.