You may have wondered about the definition of global warming, given the amount of press coverage the topic receives. Any definition of global warming should acknowledge that it is a natural process, enhanced by human agricultural, industrial and transportation activity.

A Simple Definition Of Global Warming

As sunlight enters the Earth’s atmosphere, it warms the continents and oceans. At night, this energy is radiated out into space. Global warming occurs when more solar heat is stored in the atmosphere than normal. This extra heat contributes to average increases in the temperature of the Earth’s atmosphere.

Agents Of Change

The elements that have the most influence on solar heat exchange are gasses in the atmosphere called greenhouse gasses. These gasses included water vapor, carbon dioxide, methane and other traces gasses. There are natural and manmade sources of these gasses, but it is the increase in manmade production of these gasses in that last 150 years that scientists consider responsible for the current increase in global warming.

Natural sources of greenhouse gas emissions include volcanic out-gassing, oceanic evaporation and animal biological processes. These sources tend to remain constant, although major volcanic events are evident in the geological record.

Manmade sources of green house gasses include industrial and agricultural processes. Industrially, the burning of fossil fuels is the greatest contributor to greenhouse emissions. Agriculturally, clearing of forests increases the carbon output of soil and the raising of livestock produces an abundance of methane.

The Law Of Unintended Consequences

As greenhouse gasses are introduced into the upper atmosphere, an increasing amount of heat is reflected back into the lower atmosphere. This reflected heat leads to an overall increase in average atmospheric temperature. Some scientists estimate the Earth’s average temperature has raised 1.33 degrees Fahrenheit over the last century.