The jury is still out, though the preponderance of evidence points to AGW being real.
The folks arguing against it are doing so because they are resisting change. They don't want to change in their lifestyle or perceive action taken to address AGW as a threat to their livelihood. Certainly the oil lobby does opposes it because their profits are potentially impacted.
The folks arguing for it are doing so because they want change or are scared what might happen if they don't change. These are businesses who think they'll benefit from the changes and regular folks who perceive a threat to the globe.
For myself, I don't know. However, I think we should use this as an opportunity to live more sustainably and impact the environment less. Instead of dominating the Earth with an iron fist, instead be caretakers of all species and environments.