I think the lack of efficacy of most protests and various alternative causes stems mostly from the fact that nearly all of their functions are based around promoting "awareness". People love awareness. I'm sure that awareness is indeed important, but I think that more emphasis should be placed on action rather than awareness... But I don't think that the action needs to be violent, it just needs to be action. The efficacy of action doesn't inherently depend on whether it's violent or not, there are many other factors, and I think the accuracy of the action is a big one.
To paraphrase something I read somewhere... We can all be very aware and pack all of our garbage into sorted and neat little containers and park it out on the curbs but the neighbourhood's cleanliness depends on the garbage man in the end. If he doesn't come around to pick up the garbage no amount of coming together for "awareness" is going to get the place any cleaner. You have to take action and address the garbage man or get someone else to be the garbage man.
If you want a corporation to devote 3% of their profits to developing more environmentally friendly practices you have to bring the issue to them. You can't just hand out pamphlets to people who won't read them. You have to go to the corporation and tell them what you tangibly plan to do to encourage them and what you're going to do if they don't. Sometimes it will be legal, sometimes it will be legal, sometimes it will be violent, sometimes it won't, sometimes it will require playing a part in the system, sometimes it requires being an outsider but it will be efficacious. That's not to say efficacy is the number one priority...
Non violence is effective when the people acting are useful and not just nuisances. Violence won't even be that effective if you're not that useful... not unless you plan to use a lot. Sic, if a bee stings you, do you swat it? Or do you bend to it's will? What if a small dog bites you? What if a fucking gorilla grabs you? I don't think the anarchy movement is a gorilla at this point, I'm not even sure that it's a small dog... So I'm not sure how well you think this violence thing is going to work for your cause...