Quick Facts

Climate Change versus Global Warming

• According to the National Academy of Sciences, the phrase climate change encompasses changes in temperature, precipitation and wind lasting for an extended period of time. While global warming refers to an increase in the temperature at the atmosphere near the earth's surface.
• Research and analysis of evidence dating back millions of years ago show intervals of warming and cooling on earth. The current warming trend is particularly important because it is proceeding at an unusual rate, likely caused by human activity.
• The earth has warmed 1.3°F over the past century and climate model predictions indicate that average global surface temperatures will rise 2 to 11.5 degrees F during the 21 st Century.
• Analysis has determined that greenhouse gas emissions are increasing -- due to human activities, including burning fossil fuels and changes in land use -- rather than natural causes.
• Climate change will not occur uniformly across the world. Variations in solar and geographic factors will cause regional climates to change at varying rates and magnitudes.

Greenhouse Effect

• The greenhouse effect is a natural occurrence that helps regulate the earth's temperature. Without its warming effect, earth would be uninhabitable.
• Light from the sun passes through the atmosphere and is absorbed by the earth's surface. Some energy is emitted back into the atmosphere as heat. The heat, which would usually be released back into space, is trapped by greenhouse gases. The trapped heat raises the atmospheric temperature and the Earth's surface.
• The greenhouse effect was first described in the mid to late 1800s. By the 1930s, scientists had observed that the earth was warming.
• Around the time of the Industrial Revolution, atmospheric concentrations of carbon dioxide, methane, and nitrous oxide began to increase. This increase has been partially attributed to human activity and deforestation. During the 1960s, scientists and researchers began to notice a strong relationship between the increasing level of carbon dioxide and average global temperature.

Greenhouse Gas Emissions

• Total U.S. emissions have risen by 16.3 percent from 1990 to 2005 -- a trend that is expected to continue at about one percent per year.
• Greenhouse gases include carbon dioxide, methane, nitrous oxide, a number of fluorinated gases and water vapor. Some gases, including water vapor and carbon dioxide, occur naturally, while other, chlorofluorocarbons, are produced by human activity.
• The largest source of greenhouse gases in the U.S. is carbon dioxide emissions from burning fossil fuels. A majority of these emissions come from large power plants and factories. Transportation, industrial processes, agriculture, land use and waste management are also heavy contributors to greenhouse gas emissions.
• Individuals contribute to greenhouse gas emissions in a variety of ways, including driving a car and burning oil or gas for home heating. A person's refuse and recycling habits can also contribute to emissions.

Effects of Climate Change

• Some changes to the ecosystem have already begun to take place. Increased floods and droughts due to climate change are predicted to increase the potential for plant and animal extinction.
• Warmer temperatures can increase air and water pollution, which can impact human health . Ecological changes can result from changes in the range of some parasites -- leading to increased incidence of infectious disease.
• The impact of climate change on agriculture is double-sided. On the one hand, longer growing seasons caused by warmer temperatures mean increased food production. But weather extremes threaten to adversely affect crop production. Climate change's impact on agriculture will vary regionally.
• Scientists have predicted that polar regions can expect to warm more than any other part of the world -- due to the reflectivity of ice. Melting of this ice, and snow as well, reveals darker land which increases absorption of the sun's heat -- further warming the planet.
• Sea levels have risen worldwide approximately 4.8 to 8.8 inches during the last century. Warmer ocean temperatures, melting of mountain glaciers and small ice caps, and melting of the Greenland and Antarctic ice sheets are all primary factors contributing to a rise in sea levels. Scientists predict that the global average sea level will rise by seven to 24 inches by 2100 from thermal expansion alone.

Sources
Intergovernmental Panel on Climate Change
U.S. Environmental Protection Agency
Pew Center on Global Climate Change

Return to Climate Change Media Toolkit