Weather Rusty: I agree with the statement that there is not enough evidence to proclaim anything one way or another.
That is not quit what I meant to imply!
There may not be incontrovertible evidence but the evidence in support of AGW is numerous.
Atmospheric CO2 has increased due to human activities. Not much question about that.
Atmospheric CO2 is without a doubt a significant absorber of infrared radiation contributing approximately 12% to the global greenhouse effect. A doubling of the stuff will impose an additional positive radiative forcing of 3.7W/m^ within the troposphere.
The atmospheric greenhouse effect is responsible for about 33C/50F degrees of surface warming beyond that of direct solar insolation alone. The Earth's surface receives nearly twice the warming radiation from it's own atmosphere than it does directly from the Sun.
Direct insolation has not increased over the past 50 years, the very period of greatest warming.
Water vapor, the principle greenhouse gas, is primarily dependent on preexistent temperature for it's atmospheric mixing ratio. It acts as a feedback to varying temperature. It cannot by itself alter climate.
Coupled atmosphere/ocean phenomena such as the PDO, ENSO and AMO etc. are examples of internal climate variability rather than external forcings and cancel out over their positive and negative phases.
You can always play the uncertainty card and claim small climate sensitivity to initial warming by poorly documented cloud albedo effects and clear sky upper air drying (Linzden & Spencer). You can assert without strong confirmation a connection between galactic cosmic rays and low level cloud formation (Svensmark). These ideas and others should not be disregarded out of hand, however they lack supportive evidence to a much larger degree than CO2's known physical qualities and the importance of radiative forcing on the climate system.
Because of the great complexity of the climate system, we should regard AGW to be real by strong inference, if not positive proof. If science is forced to prove to a certainty the emergent qualities of such a complex system, we will be waiting for a long, long time and be effectively paralyzed to act.