Reporting on global warming in the media is far too often of the "he said/she said" type that just leaves the impression with the reader that is controversial and there is no way for the reader to work out what is really happening. So I should point to this article in the Wall Street Journal which does a good job of informing the reader about why scientists believe that people are largely responsible for the current global warming.
My only quibble is this bit:
Earth has warmed 1.4° Fahrenheit over the past 100 years. Skeptics concede that.
Most skeptics concede that, but some of them are still going on about the "urban heat island" effect, even though it makes no difference if you throw out all the data from stations near urban centres.
Roger Pielke Sr. has posted a few rebuttals:
http://climatesci.atmos.colostate.edu/2006/05/15/wall-street-journal-qu…
From the linked article:
This assumes an independent identically distributed model (IID), of which the climate is not. Long-term perstence (LTP) needs to be accounted for, and that probability of 0.000004 might well fit into the expected variance. For more info, see:
Scale invariance for Dummies
http://landshape.org/enm/?p=13
"Earth has warmed 1.4° Fahrenheit over the past 100 years. Skeptics concede that."
Not exactly:
"The total warming since measurements have been attempted is thought to be about 0.6 degrees Centigrade."
http://junkscience.com/Greenhouse/
Steve Milloy is the Kent Hovind of "climate skeptics". I think it's safe to consider him nonrepresentative.