An Overview of Global Warming
Global warming refers to the increase in the earth's average temperature that occurs naturally or, as theorized in recent years, is induced by human activity. Most discussions on global warming today cite a correlation between an increase in global temperature and the increase in carbon dioxide, nitrous oxide, methane, and chlorofluorocarbons (CFCs) in the atmosphere. Human activity increases the amount of these gases in the atmosphere and, as a result of the greenhouse effect, increases the earth's temperature. As the earth's temperature rises, glaciers melt, ocean levels rise, and unusual weather patterns occur. Scientists warn of the loss of ecosystems and the endangerment of human lives and communities as a result of climate change.
The ozone layer also plays a critical role in global warming. The ozone layer refers to an upper layer of the earth's atmosphere containing a high concentration of ozone gas that absorbs potentially harmful ultraviolet radiation. Scientists have made the case that CFCs, which were non-existent until the twentieth century, are responsible for depleting the ozone layer.
The National Academy of Scientists and other international groups agree that global warming is occurring. Scientists who disagree cite the discipline of climatology as being too new to be able to deliver accurate data. Others believe some data has been skewed to conform to popular opinion, or simply ignored.
Most scientists also agree that global warming is the result of human activity. Opponents argue that the correlation between higher levels of greenhouse gases and the earth's warming trend do not necessarily mean that the greenhouse gases are causing the trend. Many see warmer temperatures as part of the normal fluctuations that occur over long periods of time. They also cite the ability of naturally-occurring volcanic eruptions to cause temporary changes in weather patterns and levels of gases in the atmosphere.
The body of research on global warming undertaken during the twentieth century has resulted in many governmental policies that affect individuals, business, and industry. Environmental regulations, and their effect on businesses, fuel the controversy surrounding global warming.
Basic Definitions and Concepts Related to Global Warming and Climate Change
Climatology: Climatology is the scientific study of climate. Climatologists study the weather of a specific region over a given time period. The study of ancient weather conditions, paleoclimatology, examines the weather of past millennia by analyzing natural evidence that remains in soil, tree rings and ice cores. Historical climatology focuses on the weather conditions of human history, or the climate of the last few thousand years. A study of the number of hurricanes in a given region, over the past 100 years, would be an example of historical climatology.
Environmental Regulation: State and federal statutes intended to protect the environment, wildlife, land, prevent pollution, over-cutting of forests, save endangered species, conserve water, develop and follow general plans and prevent damaging practices.
Fossil Fuels: Depletable energy sources, such as oil, natural gas, and coal, which were formed organically millions of years ago.
Greenhouse Effect: The natural ability of the atmosphere to trap solar energy in amounts that provide temperatures adequate to sustain life. Currently the earth's average temperature is 59 degrees Fahrenheit (15 degrees Celsius). Increased levels of carbon dioxide, chlorofluorocarbons, methane, and nitrous oxide trap more energy as it radiates from the planet's surface, raising the global temperature of air and ocean water.
Greenhouse Gases (GHGs): With the exception of chlorofluorocarbons (CFCs), which are synthetic, greenhouse gases are naturally-occurring gases found in the atmosphere that can absorb electromagnetic radiation and, with the exception of ozone, are dispersed throughout the atmosphere. The gases include carbon dioxide, methane, water vapor, ozone, and nitrous oxide.
Carbon Dioxide (CO2): A gas that occurs naturally and is produced by the burning of fossil fuels (most notably in cars and other vehicles) and deforestation.
Kyoto Protocol: An agreement ratified by over 160 nations that have agreed to reduce carbon dioxide and other emissions. Named for Kyoto, Japan, where the agreement was signed in 1997.
Ozone (O3): A poisonous gas that occurs naturally in the stratosphere. It forms a thin layer approximately 10 to 25 miles above the earth's surface that helps to block ultraviolet radiation.
Ozone-Depleting Substances: Defined by the United States Environmental Protection Agency (EPA) as any chemical that breaks down under ultraviolet light and releases chlorine or bromine atoms. These include CFCs, halons, methyl bromide, carbon tetrachloride, and methyl chloroform.