It seems some of the biggest concerns are: humans as a whole having too many children, humans as a whole living way longer, too much stuff especially plastic, and too many toxic man-made chemicals--which includes the public consuming buying too much, but also a lot is on big corps.
As for too many kids: this is one of the bigger "elephants in the room" not many want to talk about it; it's taboo for some reason. I think too many humans believe it is a Right to have children, no matter what. It should be a privilege, though I don't have an answer for the best way to manage it. Society propagates this by endless social conditioning and by calling anyone who does not want children selfish, ffs.
Obviously humans are animals and wired to procreate. However humans are able to see the big picture, compared to other animals. I mean, if the deer population is too high what happens? Diseases, no food, death, maybe extinction. No earth animal can be so numerous that it snuffs out all its survival resources (food, water, space). Balance. Humans need to get over themselves; we are not that special. Maybe the Earth is telling humans that. Yo, you're part of the ecosystem like everything else.
As far as people living longer: I agree this is also a major issue, like someone said, too. And for what? Humans are now obsessed with quantity of life, not quality...even when people themselves want quality over quantity, they are forced to live. Humans have become soooo fearful of death. No we shouldn't be killing people, that's messed up. But why would anyone in their elder years if they are so sick etc want to be kept alive by "modern" medicine just to sit and exist in misery? To say they made it a few more years, in pain and suffering and depressed? The right to die campaign for like people over 70 or something would help this. Help them die humanely. btw, the keeping humans alive for as long as possible no matter what is not only the increased fear of death, but also businesses squeezing out money for as long as possible.
And humans need to culturally become better at accepting death. It's part of life. I think some native cultures even had a thing about dying well. And that nearing death/old age is a journey too, just like life. It's sadistic how we force people, usually old, to live when, if they want to, would be better off to be helped to process life/death and then helped to die peacefully. Death gets all; shouldn't we try and make it less of a horror? Humans have the potential do that, but don't. Warehousing people needs to stop. It's all about money, control, and some weird moral high-horse of you must live as long as possible no matter what or else. I mean, shit, animals are treated better. Think a horse with 3 broken legs. What do we do? kill it (humanely) cuz it will have no quality of life. Your dog has a serious illness, probably won't get better---put it down cuz that's nice. Humans though? Nah, they must suffer even if they would rather die. Plus, old people are shoved into some out of sight and mind corner of society, not valued, and forced to live in pain and misery and that's somehow doing no harm and moral?! Wow! Humanity sucks.
The trash, consuming etc: all these man-made chemicals are a huge problem but we are taught we need them. It's a vicious cycle: bunch of toxic chemicals in the food, water, air so then people get sick from them, and what is the solution? Buy more stuff and chemicals to "fix" it. Think of all the products aimed at ailments that are either probably caused by or made worse by modern chemicals and "modern" medicine.
Which the Pharma industry is big on this: humans ingest tons of toxic chemicals cuz that's life now and no avoiding it at this point, we're saturated in it, but then Pharma sells you more chemicals and companies sell you products of chemicals (in plastic) to fix it. And if you think Pharma wants people well? Rofl, sick people bring them billions of dollars!
Companies need to be regulated or forced more. We are told to stop using plastic. Ok, but some stuff is almost impossible to buy not in plastic. Not our fault. And stuff in glass bottles etc is often more expensive so what are the poor supposed to do? Companies only care about money. For example, a dentist told me once don't use hard bristle brushesbad for enamel, mouth health. Oh, ok. I said, why do the companies sell them then, certainly Crest etc would know? Answercuz people buy them, was dentist's reply. So don't buy them. Ok. But there are so many things we are trained to think we NEED. And in toothbrush case, shouldn't Crest etc do the right thing and just not make nor sell a product they know isn't even needed and actually is hurtful.
The West is trained to show love, appease boredom, fix self esteem, celebrate by buying a bunch of stuff. Consumer culture and throw away culture are big. Maybe the younger generations will teach their kids different values, see through the marketing etc.
And I doubt humans have the power (bar a nuclear holocaust) to literally kill off the whole planet. Other species would rise up when some die. It's sad, but life. Yes we need to stop our extreme impact, if possible. But tbh, the current way humans are is not sustainable and usually on earth huge changes cause suffering for lots of species; it just is, we need to mitigate that as much as possible.
The real issues of too many babies, forcing old people to live as long as possible when they don't want to with no quality plus warehoused and ignored and abused, and too much stuff and chemicals.
All those things are never actionably addressed. And bigger corps and govs do nothing about those. It can't be all on the average citizen either. And it needs to be faced that religion is also in the way, no offense meant, but the forcing people to live forever and to have tons of babies probably does stem from religion to some degree (go forth and multiply, humans are superior to all animals, death is bad so avoid at all costs). These attitudes aren't working out well. I wouldn't know how to change humanity's attitudes.
You know, sorry, but it could be at a point where we might have to accept that while the planet and humans might not literally die out, suffering and change has to happen. Consequences. Maybe the Earth is helping herself and humans with fires, diseases, etc and forcing humans to change cuz we are not capable, obviously, to. Harsh, but worth considering. I mean 8billion humans with many competing ideas, philosophies etc are probably never going to agree, on anything. Perhaps the Earth will step in and fix it for us, and no, it won't be all pretty but shit has consequences and unfortunately suffering happens on Earth, which the humans make 100x worse than even nature could do ffs, for themselves especially.
The blame game has to stop and literally look at the issues and accept that there is not gonna be a rosy, rainbow, happy, smooth sailing departure from our current mess to a better one.
I have no real solutions. I'm part of the problem too. We can all try our best to be part of the solution, but we aren't gonna be able to fully force others to, and I also think eventually humans are going to HAVE to rely on nature and not man-made stuff, and I say that as someone who likes lots of the tech etc and loathes being in nature. I actually hate nature and avoid the outdoors if I can, aside from a few aspects of nature I like, but I respect it, and realize we as human animals need it to live.
The real issues are taboo, and that seems much of the problem maybe?