Increased CO2 is the only reasonable forcing so far; water vapour, methane, etc. have too short a half life in the atmosphere. The bulk of the CO2 increase is a

Increased CO2 is the only reasonable forcing so far; water vapour, methane, etc. have too short a half life in the atmosphere. The bulk of the CO2 increase is anthropogenic in origin, ergo the warming is caused by humans - no models necessary.