Global Warming Basics

Global Warming Background

• The term "global warming" refers to an increase in the average temperature of the Earth's atmosphere near its surface, either from natural or human causes, which may result in a change in global climate patterns.

Greenhouse Effect

• The greenhouse effect is the normal trapping of the Earth's heat in the lower atmosphere, due to the conversion of light into heat as it strikes the Earth's surface.
• This natural process helps regulate extreme temperature fluctuations.

Greenhouse Gases

• Gases present in the atmosphere, including carbon dioxide (CO2), methane (CH4), water vapor, nitrous oxide (N20), and CFCs, trap heat and contribute to the greenhouse effect.
• The concentration of these gases can change, leading to an enhanced greenhouse effect.

Increasing CO2 Concentration

• The concentration of carbon dioxide in the atmosphere has risen from 315 parts per million (ppm) in 1960 to 391 ppm in October 2012, compared to the estimated pre-Industrial Revolution level of 280 ppm.

Earth's Temperature Fluctuations

• The average global temperature fluctuates over time, with natural fluctuations occurring throughout history.
• The Earth's temperature has been warmer in the past, with geologic evidence of an ice age in the upper Midwest of the United States.

Causes of Global Warming

• Global warming can have natural or human causes, including:
  • Natural causes: volcanoes, animal waste, and changes in the sun's intensity.
  • Human causes: combustion of fossil fuels, increased animal waste production from livestock, and decomposition of trash.

Human Contributions

• Human actions, such as burning fossil fuels and decomposition of trash, are primary contributing factors to increased greenhouse gas concentrations, specifically carbon dioxide and methane.