An article posted on the PBS Newshour web site http://www.pbs.org/newshour/extra/features/world/july-dec12/syria_07-17.html claimed:
The International Committee of the Red Cross (ICRC), a Geneva, Switzerland-based organization dedicated to protecting victims of armed conflict and providing humanitarian aid, is the group tasked with officially declaring that a conflict has met the qualifications for civil war. The ICRC holds this responsibility because of its position as the keeper of the Geneva Conventions.
This is not the case. The ICRC’s claim is not a legal decision bringing IHL into force. IHL comes into force when such a conflict takes on certain characteristics such as when a certain level of protracted violence has been reached.
That this claim is met is an empirical question determined by the facts on the ground – regardless of what anyone says . Even if the ICRC did not say an armed conflict existed this would not change the facts on the ground. And it happens to be true in this case. Thus, at least, Common Article 3 of the Geneva Conventions applies in the case of Syria
However, It does not seem to be the case that an Additional Protocol II conflict exists. The Free Syrian Army (FSA), though is may be under a responsible command, does not appear to hold enough territory to make the conflict qualify.
Nonetheless, the ICRC’s claim that a civil war is in progress and that therefore IHL applies does lend credibility to those who make this claim.
What is an interesting question is at what point does/has this conflict become internationalized.