It is far from obvious whether the best strategy is for the U.S. to clean up its 4.5% contribution, or to use those same resources to help the Philippines clean up their vastly larger share.
Edit: I'm being glib, but seriously, this isn't necessarily a resource-intensive issue for the US to engage in. This kind of thing should be achievable purely through diplomacy. Surely there are some attractive incentives a nation like the US can bring to the table in the interests of compelling a nation like the Philippines to clean up its act, you know, like bringing a Nike executive to the meeting.