Greenhouse Gases

GREENHOUSE GASES

A greenhouse gas (sometimes abbreviated GHG) is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range.

The primary greenhouse gases in the Earth's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone, these gases greatly affect the temperature of the Earth.

Human activities are responsible for almost all of the increase in greenhouse gases in the atmosphere over the last 150 years. The largest source of greenhouse gas emissions from human activities in the United States is from burning fossil fuels for electricity, heat, and transportation.

• Overall average annual temperatures are expected to increase.

• Global warming will decrease snow, sea ice and glacier coverage, resulting in rising sea levels and increased coastal flooding. Rising temperatures will also thaw permafrost in the Arctic.

• Storms and heat waves are likely to increase in frequency and severity.

• Many wild species will have difficulty adapting to a warmer climate and will likely experience greater stress from diseases and invasive species.

These changes have both positive and negative effects on people, society, and the environment—including plants and animals. Because many of the major greenhouse gases stay in the atmosphere for tens to hundreds of years after being released, their warming effects on the climate persist over a long time and can therefore affect both present and future generations.

Human health impacts

• Increased temperatures and more frequent and severe extreme weather events could lead to increased risks of death from dehydration and heat stroke, and injuries from intense local weather changes.

• There may be an increased risk of respiratory and cardiovascular problems and certain types of cancers, as temperatures rise and exacerbate air pollution.

• The risk of water-, food-, vector- and rodent-borne diseases may increase.

Economic impacts

• Agriculture, forestry, tourism and recreation could be affected by changing weather patterns.

• Human health impacts are expected to place additional economic stress on health and social support systems.

• Damage to infrastructure (e.g., roads and bridges) from extreme weather events is expected to increase.

http://www.ec.gc.ca/indicateurs-indicators/default.asp?lang=en&n=D4C4DBAB-1

http://www.infoplease.com/ipa/A0004686.html

http://www.epa.gov/climate/climatechange/science/indicators/ghg/index.html

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