> We've clearly exceeded the carrying capacity of Earth
I’m curious to hear what leads you to this idea. Global warming is really the only major threat (well, covid too) our entire species faces but that is just a cultural/political issue and is largely technologically solved. All other issues that would stop our species from expanding are solved to a large degree (at a level where they don’t threaten our species growth).
The collapse of fisheries worldwide, soil degradation across nearly all arable land currently in use, broad ecosystem collapse (see decreasing numbers of insects worldwide). All of these are signs of unsustainable use of the planet's resources. Hell, absent fertilizers from fossil fuels, the green revolution (and subsequent population boom) wouldn't be possible.
There are too many people living living lives that consume too many resources currently. While we've slowed our growth, we're going to shrink our resource utilization absent extra capacity from space. That reduction will either be managed or unmanaged reduction (e.g. collapse).
All of those aren’t going to make humans extinct though. Are we potentially ruining the earth? Yeah probably. But the human race could certainly survive long term with no soil and no ocean animals.
Soil degradation, ocean acidification, basic resource scarcity (running out of copper or phosphates for example)
Others which come to mind that are "fixable" through technology vs psycho-cultural features:
Overfishing - > global enforceable legislation of the seas
Meat consumption - > high quality meat analogs
Plastics endocrine disruption - > improved discovery of protein folding to discover problematic endocrine disruptors
Batteries - > novel types of battery chemistry
Lack of Water - > drip irrigation, desalination (desertification itself can't be per se fixed)
Lack of Energy longterm - > SPARK, ARC nuclear type reactors
Even soil degradation could be tackled with GMO crops and improved nitrates/phosphates, it would not be ideal because these also generate toxic algae blooms on river deltas but "would make do". Ocean acidification is the scary one just like most other effects related to global warming
I’m curious to hear what leads you to this idea. Global warming is really the only major threat (well, covid too) our entire species faces but that is just a cultural/political issue and is largely technologically solved. All other issues that would stop our species from expanding are solved to a large degree (at a level where they don’t threaten our species growth).