The big issue is why this warming trend is occurring. Imagine a greenhouse with large glass panels on all sides. Solar energy passes through these panels, warming the interior. The glass panels prevent heat from escaping, and warm temperatures prevail inside. Earth's atmosphere behaves in a similar way.
Solar radiation penetrates the atmosphere and is absorbed by Earth's surface.
Some of this energy reflects back toward the atmosphere, but certain gases trap it, much like the glass of a greenhouse. The proper mix of gas concentrations stabilizes global temperatures. A shift in this complex system can alter Earth's temperatures and its ability to sustain life. For this reason, global climate change is a worldwide concern. Click here to take ENN's global warming quiz.