global warming

One of the most hotly debated topic on Earth is the issue of climate change. Surfing through http://www.ncdc.noaa.gov/oa/climate/global warming.html , I learned that knowing how the world's systems are changing and how they have changed in the past is crucial to understand how they will change in the future. Besides that, there many things I ponder on after reading on global warming. One of those questions are what is the greenhouse affect and is it affecting our climate? I am definitely worried about the future and thinking about mother nature's cruel ending scares me! It is high time we realise it.