Why Are Greenhouse Gasses Compared to a Blanket?

Features

• The greenhouse effect is actually essential to life on Earth. According to "Essential Environment," without it Earth's surface might be as much as 59 degrees Fahrenheit colder on average. Like a blanket, greenhouse gases help keep temperatures on Earth's surface warm enough for life. When it comes to greenhouse gases, however, it's possible to have too much of a good thing.

Function

• Solar radiation passes through Earth's atmosphere and is absorbed, increasing the surface temperature; as the Earth's surface warms, it radiates heat in the form of infrared radiation. Greenhouse gases absorb and re-radiate some of this infrared radiation back to Earth. Just like a blanket, the greenhouse gas helps to keep in the heat that might otherwise be radiated out into space.

Significance

• According to the Intergovernmental Panel on Climate Change's Fourth Assessment Report in 2007, average surface temperatures on Earth increased by roughly 1 degree Fahrenheit over the course of the 20th century. The IPCC report also found that atmospheric CO2 concentrations had increased from 280 parts per million before the Industrial Revolution to 379 ppm today. The authors concluded that these changes were due primarily to human activity, especially the burning of fossil fuels.