Global Warming

Global warming

What is the greenhouse effect, and is it affecting our climate?

The greenhouse effect is unquestionably real, and is essential for life

on Earth. It is the result of heat absorption by certain gases in the

atmosphere (called greenhouse gases because they trap heat) and re-

radiation downward of a part of that heat. Water vapor is the most

important greenhouse gas, followed by carbon dioxide and other trace

gases. Without a natural greenhouse effect, the temperature of the Earth

would be about zero degrees F (-18C) instead of its present 57F (14C).

However, the concern is not with the fact that we have a greenhouse

effect, but it is with the question regarding whether human activities

are leading to an enhancement of the greenhouse effect.

Are greenhouse...