Brian Ganek wrote:citizenschallenge wrote:..."The only way to prove with 100% certainty that humans are responsible for global warming would be to run an experiment with two identical Earths – one with human influence and one without."...
The only way to experimentally test is to design an experiment with two Earths? Who wrote that? They haven't heard about single subject experiments ? I've posted links before, these designs are commonly used in behavioral, physiological and medical science. Simply put, treatments are random over time and the theorized "cure" is measured to see if it correlates with the treatments.
What you're saying is, there are no compelling experimental tests because it's impossible; are you sure your AGW sources understand science?
Well heck Brian, give us a break you've been offered sources to such information for at least a year and a half.
Why not try a study session?
Take the time to do some serious studying and learn about what you wrongly imagine does not exist, there are many more sources, but this is an excellent starter: