The greenhouse effect keeps the earth warm and habitable; without it, the earth’s surface would be about 60 degrees Fahrenheit colder on average. Since the average temperature of the earth is about 45 degrees Fahrenheit, the natural greenhouse effect is clearly a good thing. But the enhanced greenhouse effect means even more of the sun’s heat is trapped, causing global temperatures to rise.
Scientists refer to what has been happening in the earth’s atmosphere over the past century as the “enhanced greenhouse effect.” By pumping man-made greenhouse gases into the atmosphere, humans are altering the process by which naturally occurring greenhouse gases trap the sun’s heat before it can be released back into space.
Click here for a larger version of this image. [1]