Skeptics; do you have a complete alternative theory to explain the warming?

The complete lack of scientific integrity that comes from alarmists is revealing. They are simply political leftist pretending to understand science. The answers from the alarmists are extremely revealing. The theory that CO2 is causing the warming is not a complete theory to use your description. It is at best a very bad theory. The answer to your question is that you don't know. You are going to have to live with that. You cannot use your ignorance of the cause to blame humans although it never stops alarmists from tryign. Alarmists simply don't know enough to know they don't know enough.