is still mind bogglingly massive. There is more than enough room for all of us

"us" gets larger and larger every year, and the only way to prevent that fact is to restrict people being able to freely have kids.

The ecosystems and the lives within them have a right to exist because they already exist,

No. They have no more a right to exist than the undisturbed rocks that existed before trees moved up and took them over did. They have no more right to exist than humanity.

Rights do not exist in nature, they don't exist to anything but social, empathetic, species who benefit from giving each other rights. Rocks, plants, animals, and so on, have no "rights", no more than what we so decide to give them.

Just because we as humans superior and arguably more important, it doesn't mean that every other life form should be considered expendable

To live means to destroy other life to do so. In your life, you have likely killed thousands of animals, bugs, used resources derived from the corpses of hundreds of living things, and you a support a society that does more of that ever day.

You want to back up your idea that these things have a right to live, a right equal to your own, and that one should seek to do no harm? There is only one solution, and I am sure you won't be a fan of it.

We aren't happy, nice, creatures. To live, we must kill, we must destroy the existence of others, and we must do so by nature of that we have to eat, we are born as we are. The only way to avoid it is to die, and allow animals/plants/etc to take our place, ones without a silly sense of morality or rights given to things which shouldn't have them.

The fact that our activity can be so disruptive to wildlife, to ecosystems, and to biodiversity just further underscores how important it is for us to engage in responsible, sustainable behavior.

For our own benefit, yes. We rely on these creatures to live, and must ensure these creatures are maintained to a level that ensures humanity will continue to have wood, tuna sandwitches, and so on.

A world powered by farm-towers and tuna-farms, where CO2 is maintained by a network of machines, regulated by mankind, is far better, for more happy, more meaningful, than one of nature that serves the same purpose. The world, when all it's resources are devoted to the feeding and care of humanity, will be one that is good, not negative. The wiping out of nature will cease to be bad the moment we no longer rely on it.

Of course, we will always seek to have evolution, to explore the forests, and so on, we should always have some nature preserves. However, every one of those means resources that could be the source of hundreds of human lives, if not thousands. They come at a cost, or will do so, once all other resources are captured within our economies, should they learn to be self-contained.

Nature, through its own automated mechanisms both brutal and beautiful, creates environments like this.

Better a world of nothing but trash and huts, with humans inside them than a world of trees where not a single person lives.

In those trees is this:

NSFW:

Nature is brutal, amoral, has no memories, writes no stories, saves no lives. Nature, those trees, may be beautiful, pretty to the eye, but it will be better done away with.

Humanity, in the short time we have existed, gone from a species where these things are a regular occurrence, to a species where these things are horrible, tragedies, that rarely happen. You want a world with the most happiness, the most kindness, the most love? You want a world of humans. You want one with the above, with animals tearing out the throats of other animals, eating them alive? You stick with nature.

It won't appreciate your help, either.