Global Warming - Advanced

1. When radiation from the Sun passes through the Earth's atmosphere, it strikes the Earth's surface and bounces back into space.  If this radiation does not bounce back into space and instead becomes trapped by the Earth's atmosphere, it will become heat.  Human activity has increased the concentration of gases that trap the Sun's radiation.  These gases include carbon dioxide.  These trapped gases cause the effect.

2. The United Nations established a panel to study climate change in 1988.  This panel concluded that during the 20th century, the Earth's temperature warmed by about degree(s) Fahrenheit.