I do think we are treating the planet horribly. Just one look at the amount of plastics in the ocean shows this. I don't think it's too late though. We can clean up the ocean, and prevent trash from entering it. The advancements in technology are encouraging though. Efficiency in solar power means we can improve our desalination and provide more fresh water.
You're right, we can, but will we? It's not being done right now, not on a massive enough scale and the damage done outweighs the good.
That is true. There are some group projects that clean some rivers, but we need a global effort with government coordination for the oceans.
Massive action is what is required, but I don't see it happening and so the decline of the humankind will continue.