One: Is the only alternative war? No. Sanctions work. Two: Is it already too late (assumes some tipping point and some amount of waiting)? Sanctions take a while; if a tipping point exists (defer to science), then maybe yes. If no tipping point exists, then no (in the absolute as your question implies) but maybe yes in a localized harm sort of way.
War is can address the problem of permanent environmental destruction. It has human costs and is certainly not environmentally neutral. Wouldn't it be nice if there was any other solution?
Do they? And at what human cost?
Probably not. People have a really hard time when cause and effect have a big time gap, and separately are really bad with big numbers — people, areas, money, everything.
Also, while I have heard that rainforests causes rain, it is a surprising thing to hear.