In the following Op-Ed piece, published exclusively by TPR, National Trust for Historic Preservation President Richard Moe makes the case that the preservation of buildings may be the greenest building practice of all. Having addressed an L.A. Conservancy gathering earlier this month, Mr. Moe also clearly understands what more or coming to believe in L.A.: that the region's ambitious green building and adaptive reuse policies can go hand in hand as powerful tools to substantially improve the carbon footprint of the buildings that populate the region.
Communities across the country are grappling with questions about what to do with their older buildings. While we generally think that preserving historic buildings is a way to honor our past, it's time to understand that it is also a way to protect our future.
Since 1993 I have headed the National Trust for Historic Preservation, where we recognize that while the preservation of buildings is deeply rooted in our desire for tangible links to history, it is mostly about having the common sense to hold on to well designed structures that have plenty of use left in them.
Because historic preservation essentially involves the conservation of energy and natural resources, it is really the greenest of the building arts. And in this day and age, preserving and recycling buildings can play a vital role overcoming what may be the greatest crisis and challenge of our time: climate change.
Human activities contribute to climate change, and the United States is a big part of the problem. We have 5 percent of the world's population, but we're responsible for 22 percent of the world's greenhouse gas emissions, which are the leading cause of climate change.
Much attention about reducing greenhouse gas emissions is focused on cars, trucks, trains and airplanes. But according to the Pew Center on Climate Change, the transportation sector accounts for 32 percent of America's carbon dioxide emissions, while well over 40 percent of our carbon emissions are produced by the construction and operation of buildings.
We must realize that any solution to climate change must include the continued use and retrofit of our existing buildings. That's where historic preservation can play a significant role.
Retention and reuse of older buildings is an effective tool for responsible, sustainable stewardship of natural resources, including those that have already been expended. Consider the idea of "embodied energy."
Buildings are vast repositories of energy. It takes energy to manufacture or extract building materials, more energy to transport them to a construction site, still more energy to assemble them into a building. All of that energy is embodied in the finished structure, and if the structure is demolished and landfilled, the energy locked up in it is totally wasted. What's more, demolition uses still more energy, and, of course, the construction of a new building in its place uses even more.
The use of all of that energy releases tremendous amounts of carbon into the atmosphere. For example, it is estimated that building a new 50,000-square-foot commercial building releases about the same amount of carbon into the atmosphere as driving a car 2.8 million miles.
Don't assume that the energy efficient operations of that new green building will offset the environmental costs associated with demolishing and replacing an existing building. A recent study from the United Kingdom finds that it can take between 35-50 years for a new, energy efficient home to recover the carbon expended during the construction of the house.
Also, don't assume that historic buildings aren't energy efficient. Many have thick walls and other features that enhance efficiency. Their durability allows for renewal that underscores recognizing them as genuinely sustainable resources, and sustainability, after all, is the ultimate objective of a nation and a society that values its future.
Combating climate change will require us to elevate sustainability as a priority in all facets of our lives. For too long we have assumed that natural resources would always be readily available and our environment would be resilient and support life. We now understand that this is not true. Today we are challenged to find a way of living that will ensure the longevity and health of our environmental, economic, and social resources. I am confident we will create and make available new sources of energy. We will learn to be better stewards of our communities and our planet. Our buildings and our homes will reflect that understanding and stewardship.