Yes this sounds great but the issue is about how longtermists revel in the opportunity to sacrifice near term goals for long term ones, in an almost pathological way. I still don't understand why there should be any conflict between aggressive environmentalism and longtermism, but it keeps coming up over and over again. All I can think of is that longtermists want to demonstrate how truly long-term they are and therefore act like one of the most pressing current issues is secondary to a bunch of other stuff. In general and in the absence of more info I think it's safe to go for the proximal goal of stabilizing the world's ecosystems, even though it _could_ in theory be a non-existential risk. All of that said, the conflict between longtermism and environmentalism might mostly be manufactured by the critics of longtermism, like the author of this article.