This argument always fascinates me. As is usually the case, ignorance on the subject is widespread despite everybody having an opinion.
Lets look at some simple facts that are neither for or against climate change but simply state the obvious:
1. The Earth's atmosphere is what keeps the temperature on Earth moderately constant. When the Sun's radiation hits the surface of our planet it is reflected back; the atmosphere traps some of this reflected radiation and keeps heat within the Earth's environment. Similarly, the radiation of the Sun does not hit us at full strength because the atmosphere acts as a protective buffer. The result is that we get a temperature on Earth that is fairly constant with no extremes at either end of the scale.
If we contrast this with the moon (roughly equal distance to the Sun) which has NO atmosphere, the temperature is high during daylight because the full strength of the Sun's radiation hits it's surface but plunges to extreme lows at night because no solar radiation is trapped. No life survives there particularly because of the freezing conditions.
2. There are gaseous elements and compounds in the Earth's atmosphere that trap reflected heat. These gases (often referred to as Greenhouse gases) essentially act as a blanket of insulation and prevent the Earth's surface temperature plunging to extreme lows at night.
3. Atmospheric CO2 is one of the gases that insulates the Earth. Other insulatory gases in our atmosphere include ozone, nitrous oxide and methane.
Now even without going into the empirical evidence that shows that the levels of CO2 in the atmosphere have increased significantly and that the Earth's surface temperature is increasing here are three questions that, based on the above facts, you need to ask yourself:
1. What does CO2 in our atmosphere do?
2. Are we currently increasing the levels of CO2 in the atmosphere (and have we been increasing them over the last 150 or so years)?
3. If the answer to question 2 is yes, what does that mean?
Remember, don't simply believe and repeat other peoples views. Gather the facts for yourself and come to your own non-biased logical conclusion.