What is a sustainable level of land development?
Most articles on green construction, including those provided by GreenBuildingAdvisor.com, contain information on a wide range of topics, including material choices, indoor air quality, landscaping, and the VOC content of paint. This wide array of information can convey a false impression — namely, that the covered topics are equally important.
If you're building a new house, most of these topics turn out to be irrelevant. From an environmental perspective, the most important factor by far is energy use — not energy efficiency, but actual energy consumption. Consider the following information:
"The ongoing energy use of a building is probably the single greatest environmental impact of a building, so designing buildings for low energy use should be our number one priority." — "Establishing Priorities with Green Building, Environmental Building News, September 1, 1995.
"Although important, initial embodied energy is nearly always dwarfed by the energy consumed by a building over its lifetime. … Over the first 50 years, the initial embodied energy is less than 1/12th of the operating energy." —"Embodied Energy: As Important As Low Energy Design?" by Stephen Thwaites.
"As far as I can tell, focusing on construction materials in isolation — and to the exclusion of other impacts of owning and operating a home — is a mistake. … I combed through CORRIM's [Consortium for Research on Renewable Industrial Materials] life-cycle analyses to try to find the total difference, over 75 years, between carbon emissions for a steel-framed vs. a wood-framed home. And when you add together all life-cycle carbon emissions — for manufacturing and transporting the materials, building the home, maintaining, heating, cooling and lighting it for 75 years, and dismantling and disposing of it at the end — the difference between the two isn't much more than a rounding error. … When I look into CORRIM's numbers, it's pretty clear that the big carbon impacts from a home are from heating, cooling, and electric power consumption, which typically have little to do with the choice of framing materials. Far more important than framing are the energy-efficiency features of a house. Excellent insulation, passive heating and cooling, good daylighting, and so on can make a huge difference to long-term climate impacts — far more than the choice of a wood versus steel frame. And perhaps more important than any of these is the size of a house." — "Framing: The Debate" by Clark Williams-Derry.
According to climate scientists, the burning of fossil fuels is bringing our planet close to a dangerous tipping point. To equal the global average per-capita use of energy, Americans would need to reduce our energy use by 83%. But even such a drastic reduction in energy use would not achieve a sustainable result, since the world's level of energy use is clearly unsustainable.
"Sustainable" land development?
The word "sustainable" is bandied about far too casually these days. It's easy to understand the meaning of sustainable forestry. But anyone thinking about building a new house should ask, "What is sustainable land development?" Clearly, the sustainable level of global land development is zero acres per year — or perhaps even a negative number.
So here's my advice to anyone thinking of building a new green home:
Of course, a perfectly reasonable argument can be made in favor of building a new house. But please don't call it sustainable.
—Martin Holladay is senior editor at GreenBuildingAdvisor.com
