Q: What are greenhouse gases?

A: They are chemical compounds in the atmosphere that trap the sun’s heat near the Earth’s surface. This naturally occurring phenomenon is what keeps the Earth’s temperature stable at an average of approximately 60 degrees. Without this greenhouse effect, our planet’s average temperature would not be warm enough to sustain life. Human activity, however, is producing additional large amounts of some greenhouse gases, which are disturbing this natural balance and warming the climate.

Q: Why is a warmer climate a concern?

A: Even the slightest increase in average global temperature can cause major changes in climate patterns. For example, the United States is feeling the effects of more frequent and extreme weather events. During the past several years, the Midwest has endured one of the worst droughts on record. Higher temperatures, meanwhile, are melting the snow pack that provides much of the water supply for the western U.S. Experts predict the region could lose nearly half its water supply by 2100.

Q: How much warmer are we?

A: The 1990s were the warmest decade of the century, and the first decade of this century is on track to be another record-breaker, according to NASA. The years 2002 through 2006 along with 1998 were the warmest six years since the 1890s, with 2006 the warmest in more than a century.

Q: Which greenhouse gases genereated by human activity cause the
greatest concern?

A: Carbon dioxide and methane. Emissions of carbon dioxide are produced
whenever fossil fuels, such as oil, natural gas, gasoline, diesel fuel and coal, are burned to produce electricity, heat buildings or power vehicles. Carbon dioxide levels are at their highest levels in the past 650,000 years. Methane, meanwhile, is a byproduct of organic waste and sewage decomposition. In urban areas, methane gas is produced when organic waste such as paper, yard trimmings, wood and food waste decompose in landfills. Methane is 21 times more powerful per unit of carbon dioxide.

Q: What can local communities do to reduce greenhouse gases?

A: Local governments have a substantial impact on energy use and waste practices within their communities. They can encourage building and growth that reflect traditional, mixed-use neighborhoods rather than sprawl. They can implement energy-efficient buildings codes. Or they can invest in public transit and
provide reuse, recycling, composting and other waste reduction services, to name just a few.

Q: How will government policies that reduce greenhouse gases benefit the local economy and human well-being?

A: By saving taxpayer dollars, creating job opportunities, improving air quality and reducing health ailments. Energy-efficient technologies – from high-mileage or alternative fuel fleet vehicles to energy-efficient public buildings, water and sewage treatment plants and streetlights – dramatically reduce energy expenses. Additionally, as the demand for clean, renewable energy continues to grow, cities that tap into this demand will have a competitive advantage. Renewable energy technologies, such as wind and solar power, generate more jobs in construction, manufacturing and installation than fossil fuel-based energy technologies.

Pollution-related health ailments, meanwhile, incur a significant human toll and a staggering cost. Sunlight and heat are important ingredients in the creation of ground-level ozone, which is one of the most damaging aspects of urban smog.
A nationwide study indicates a 35-percent reduction in the average daily ozone level could save nearly 4,000 lives in the 95 communities included in the study. Meanwhile, more than $3 billion is spent annually treating children under 18 for asthma, which is often triggered by unhealthy air.

Source: ICLEI — Local Governments for Sustainability