Green Building Primer (A Four Part Series) - Part III

Cross-posted from my site. Enjoy.

Part III - Statistics and Reasoning

So… what are some of the reasons and statistics to support the benefit of building green?

Regardless of whether or not you saw Al Gore’s global warming documentary, global warming is gaining the attention of the media and scientists worldwide. The building industry, including how we power these buildings, how we live in them, and what we put in them, has played a significant role in global warming.

Energy from the sun drives the earth’s weather and climate, and heats the earth’s surface; in turn, the earth radiates energy back into space. Atmospheric greenhouse gases (water vapor, carbon dioxide, and other gases) trap some of the outgoing energy, retaining heat somewhat like the glass panels of a greenhouse. Without this natural “greenhouse effect,” temperatures would be much lower than they are now, and life as known today would not be possible. Instead, thanks to greenhouse gases, the earth’s average temperature is a more hospitable 60°F. However, problems may arise when the atmospheric concentration of greenhouse gases increases.

Since the beginning of the industrial revolution, atmospheric concentrations of carbon dioxide have increased nearly 30%, methane concentrations have more than doubled, and nitrous oxide concentrations have risen by about 15%. These increases have enhanced the heat-trapping capability of the earth’s atmosphere. Sulfate aerosols, a common air pollutant, cool the atmosphere by reflecting light back into space; however, sulfates are short-lived in the atmosphere and vary regionally.

Why are greenhouse gas concentrations increasing? Scientists generally believe that the combustion of fossil fuels and other human activities are the primary reason for the increased concentration of carbon dioxide. Plant respiration and the decomposition of organic matter release more than 10 times the CO2 released by human activities; but these releases have generally been in balance during the centuries leading up to the industrial revolution with carbon dioxide absorbed by terrestrial vegetation and the oceans.

What has changed in the last few hundred years is the additional release of carbon dioxide by human activities. Fossil fuels burned to run cars and trucks, heat homes and businesses, and power factories are responsible for about 98% of U.S. carbon dioxide emissions, 24% of methane emissions, and 18% of nitrous oxide emissions. Increased agriculture, deforestation, landfills, industrial production, and mining also contribute a significant share of emissions. In 1997, the United States emitted about one-fifth of total global greenhouse gases. (Source:http://yosemite.epa.gov/oar/globalwarming.nsf/content/climate.html)

US buildings alone are responsible for more CO2. emissions than those of any other entire country in the world except China. (Source: Kinzey et al., “The Federal Buildings Research and Development Program: A Sharp Tool for Climate Policy,” 2002 ACEEE proceedings, Section 9.21.)

Global mean surface temperatures have increased 0.5-1.0°F since the late 19th century. The 20th century's 10 warmest years all occurred in the last 15 years of the century. Of these, 1998 was the warmest year on record. The snow cover in the Northern Hemisphere and floating ice in the Arctic Ocean have decreased. Globally, sea level has risen 4-8 inches over the past century. Worldwide precipitation over land has increased by about one percent. The frequency of extreme rainfall events has increased throughout much of the United States.

Increasing concentrations of greenhouse gases are likely to accelerate the rate of climate change. Scientists expect that the average global surface temperature could rise 1-4.5°F (0.6-2.5°C) in the next fifty years, and 2.2-10°F (1.4-5.8°C) in the next century, with significant regional variation. Evaporation will increase as the climate warms, which will increase average global precipitation. Soil moisture is likely to decline in many regions, and intense rainstorms are likely to become more frequent. Sea level is likely to rise two feet along most of the U.S. coast. (Source:http://yosemite.epa.gov/oar/globalwarming.nsf/content/climate.html)

Energy use is therefore extremely important to consider. Buildings represent 39% of U.S. primary energy use (including fuel input for production), and represent 70% of U.S energy consumption. (Source: 2003 U.S. DOE Buildings Energy Databook)

The savings which can be realized through the green building process, both new builds and retrofit/remodels is not arguable. Coupled with the use of Energy Star rated products for both your home and business, the immediate and long term savings are a big part of green building incentive.

For example, tenants can save about 50 cents per square foot each year through strategies that cut energy use by 30%. This can represent a savings of $50,000 or more in a five-year lease on 20,000 square feet (Source: U.S. Environmental Protection Agency). On average, green buildings use 30% less energy than conventional buildings.

Water use, material use, and waste are also heavy contenders when opting for green building. Conserving water is often as vital as saving energy. Buildings use 12.2% of all potable water, or 15 trillion gallons per year. (Source: U.S. Geological Service, 1995 data.) Many things incorporated into a green building; including the landscaping, take water usage strongly into account.

Buildings use 40% of raw materials globally (and 3 billion tons annually). Combine this with the EPA’s estimate that 136 million tons of building-related construction and demolition (C&D) debris was generated in the U.S. in a single year – and you will have an understanding for the phrase “Reduce, Reuse, Recycle.” (Sources: Lenssen and Roodman, 1995, “Worldwatch Paper 124: A Building Revolution: How Ecology and Health Concerns are Transforming Construction,” Worldwatch Institute and the EPA)

On the forefront of the green building industry has been the U.S. Green Building Council’s LEED Program.

What is LEED®?

The Leadership in Energy and Environmental Design (LEED) Green Building Rating System™ is the nationally accepted benchmark for the design, construction, and operation of high performance green buildings. LEED gives building owners and operators the tools they need to have an immediate and measurable impact on their buildings’ performance. LEED promotes a whole-building approach to sustainability by recognizing performance in five key areas of human and environmental health: sustainable site development, water savings, energy efficiency, materials selection, and indoor environmental quality. (Source: U.S. Green Building Council)

LEED’s rating system basically gives “points” in all of the above stated goals, with various levels of “green-ness.”

Several other organizations have developed their own green building guidelines, specs, and initiatives as well including: the National Association of Home Builder’s voluntary Model Green Home Building Guidelines (http://www.nahb.org), Minnesota Sustainable Building Guidelines (http://www.csbr.umn.edu/B3/), Federal Guide for Green Construction Specs (http://www.wbdg.org/design/greenspec.php), and the American Lung Association Health House Builder Guidelines (http://www.healthhouse.org/build/04HHBuilderGuidelines.pdf)

Think green!

To be continued...