This is why I detest the concept and celebration of “technically correct”. No, it’s not the “best kind of correct”, it’s being an asshole.

Basically it's due to the heat, acidification of the ocean, and the massive drop in oxygen production as the ocean acidifies.

Most of the oxygen we breathe is produced by microorganisms in the ocean and as the ocean gets more acidic (from absorbing CO2 from the air) and hotter (from greenhouse effects) it makes it harder for those little fellas to survive. And when they die their impact on our breathable air goes away. And if course the stuff that's eats those organisms no longer have food and due off.

That's not even mentioning just the heating from greenhouse effects making unlivable temperature conditions (humidity + heat = unable to cool down and overheat) more likely to occur.

All life wouldn't perish per se but the current complex animals we have (and us humans) would be greatly impacted to say the least.

Because the threat is not a nuclear winter. It’s the disruption of all environmental systems that regulate the planet that is the threat in question. Which, in turn, disrupts the food chain, which starves whatever requires that food, which is for all intents and purposes, all life.

I don’t understand how this is such a conversation with so many people here.

Why would all life perish?

All life wouldn't perish, the only things that will be left will be certain bacteria, phagocytes and viruses that can tolerate and indeed will likely proliferate in extreme environments. Everything larger then that will die of starvation due to a cascade of failing systems, likely starting with the death of the marine biosphere when the temperature rises to unsustainable levels and/or the pH lowers too much for the same effect. Though of course no one really knows what will actually happen because there are too many unknown variables.

. . . the planet and life itself will survive . . .

How are you defining “life itself”?

. . . and probably even be better off without humans.

I’d say that goes without saying.

Humans are causing the next extinction event and afterwards life will just start fresh again.

Start “fresh”? Like with single-celled organisms? Maybe a billion years later we’ll be back eating sandwiches? Okay, so what process created sustainable environments again? Humans left some sort-of-permanent damage. Nuclear waste, PFAS, etc. Sure a good ol’ pole shift and a few asteroid impacts and we’re back in business.

So no, saving the planet is not the goal. Saving humanity and most of all other current life is. And if that’s what you want to accomplish then that’s what you should talk about, specifically.

God this is fucking exhausting. The prevention of unmitigated and prolonged suffering by all sentient life is the goal, YES. Kudos to the possibly viable future space rock and the wisdom to acknowledge our utter inability to protect one single planet from ourselves is laughably inadequate and - CLEARLY - irrelevant.

Depends on if you work outside for a living or live near a coastline or a forested area. It won’t be like a Star Trek: The Original Series where everyone’s in a big room and a red glow starts pulsating and we all groan and crumple to the floor. No, it won’t be like that.

It’ll be like heat exhaustion exacerbated a hitherto unknown heart condition that deaded you. Or a Cat 6 hurricane rolled a tree over you. Or failing crops mean you couldn’t fight off COVID-26 or whatever.

No, we’re not going to all die at once, as such. Depending on your timeframe for “at once”.

Also, nobody is gay on Venus because Venus doesn't have rainbows.

Wait a minute, Venus sounds like the perfect place for conservatives! Elon, get your starship up and running and take all your buddies and musketeers to Venus! Please! I promise all liberals will stay here.

no one in venus ever had cancer

I had to double-check to make sure; but no, it isn't.

https://xcancel.com/JunkScience