Forty mayors from around the country just met at Sundance to discuss sustainability, and were addressed by Ed Mazria, founder of Architecture 2030, about the dirty impact of coal and climate change.

A recent study issued by 47 scientists shows that at 450 parts per million (ppm) carbon dioxide in the atmosphere, a "dangerous climate change" will occur with potentially irreversible glacial melt and rapid sea level rise. We are already at 383 ppm and are increasing carbon dioxide by about 2 ppm annually.

The solution? According to nonprofit group Architecture 2030, which is trying to make the building sector carbon neutral by 2030, we must take two steps. Impose a moratorium on coal and dramatically reduce energy consumption and carbon dioxide emissions from the building sector, which heavily relies on coal.

Buildings are the single largest contributor to global warming. The U.S. Energy Information Administration states that buildings are responsible for 48 percent of all energy consumption and greenhouse gas emissions annually. Seventy-six percent of all power plant-generated electricity goes to operating buildings.

In the United States, 151 new conventional coal-fired power plants are in various stages of development, and at least one new conventional coal-fired power plant is being added around the world each week.

At this rate, the cheapest and dirtiest fossil fuel will cause many of our cities, including Boston, New York and San Diego (shown in picture with five meter rise in sea water), to be underwater.

That sure makes all our other carbon dioxide-reducing efforts seem pointless. Consider this: Wal-Mart is investing a half billion dollars to reduce the energy consumption and carbon dioxide emissions of their existing buildings by 20 percent over the next seven years. That's a lot of Wal-Marts. But even if every Wal-Mart met this target, the carbon dioxide emissions from just one medium-sized coal-fired power plant would completely negate this entire effort in just one month of operation each year.