"What's usually missing from these discussions are the huge amounts of waste matter and energy costs that are produced every time a building is torn down vs. a rehab project. So what if the building is "green?" It doesn't matter much if the net byproduct is negative."

- Dmac, commenting on a post about Chicago's green aspects.

Dmac makes a valid point that building new - even if it's green - sometimes doesn't measure up versus a sensible rehab.

It's worth noting that according to Arthur C. Nelson's 2004 report for The Brookings Institute, about half the existing real estate space in the United States will be rebuilt by 2030. Green building advocates look to this sustained momentum as a catalyst to improve technology and move the entire industry forward - thereby narrowing that energy-cost gap Dmac mentions above.

See more in Comment of the day, Environment.