The "barren rock" is a bit of a strawman. Very few if any people believe that the elimination of all life on Earth is in the cards. Human life, on the other hand, is certainly possible.
For the vast majority of major extinction events in history it looks like rapid climate change was the major trigger, and at some point small changes lead to a "self-reinforcing climate resonance cascade of unforeseen consequences", and we currently don't know exactly what the limits are.
This is the focus of a huge amount of the work of Peter Ward and he has written plenty both for scientific and a popular audiences.
Now he may, of course, be wrong. But his work is credible enough that you have to at least take into account that the real risk of extinction is possible.
And how many climate scientists actually believe extinction is on the table? I've seen some say collapse of global civilization and mass death is a possibility under the worst case scenarios, but not really anyone claiming all humans would die. Anyway, the latest IPCC report puts the upper range of warming at 3.7°C. Which is bad, but not the apocalyptic hot house Earth scenario. But even with that, some environments will still be livable. People live on mountains, near likes, far inland, way up north and all over the place. Earth isn't going to turn into Venus, and it was a lot hotter when the dinosaurs evolved. Plants and animals still survived after the Permian die off.
Human life today is mostly maintain with infrastructure (water, food, security, health, etc). A cascade of failure due to climate change can destroy all but very local and small infrastructures. With society eventually returning to a pre-industrial conditions. It is not the end of humanity but the pre-industrial world economy can't support food, water safety and health care for 9 billion people. In pre-industrial era world population were less than 1 billion, we might return to these numbers. That means death of the large majority of human. Not extinction but the biggest threat in human history.
Well, hundreds of millios displaced and/or dead would be enough. Doesn't have to "turn earth into a barren rock".
And as for "suddenly", many systems tend to have a breaking point, especially systems, like the environment, which have feedback loops that can easily feed into each other and make things worse fast. Collapse is seldom linear or a nice gradual curve.
Actually, yes it does. The OP specified "human extinction". We're arguing that single point. The fact that thousands/millions/billions might displaced isn't being contended.
If that's not a "threat to all life on earth," I don't know what is. And that's just what I could find with 5 seconds of googling.
https://www.theguardian.com/environment/2019/feb/10/plummeti...
To 'wipe out' life on earth, you have to crash the moon into it or do something similarly ridiculous - remember that a giant asteroid wasn't enough.
Wiping out all human life is possible, but again I don't think that anyone is comforted by the idea that 0.1% of the population might survive in an arctic cave.
Where we seem to fail is in communicating to folks that don't want to spend money to fix the problem today how their life will become miserable tomorrow.
The loss of insects isn’t caused by climate change, it’s too much pesticide use and people trying to have lawns instead of native plants.
https://www.scientificamerican.com/article/insects-are-dying...
What is the greatest tragedy is how much worry and anxiety climate change causes. The earth is not a thinking thing - “Mother Nature” is not a being. The planet will exist and doesn’t care about humans. A century after the last human lives nature will swallow up almost everything we built. Earth exists for humans because we live here and make it so. We will adapt to whatever climate exists.
It doesn't matter what Earth was like at some point in the distant past. There weren't 8 billion humans living on it. It's not easy or cheap to move cities with populations in the millions because sea level rise puts them below water.
Humans can adapt to climate change but it's very likely to be very painful and very expensive.
Do you expect that several hundred million people who's previous land of habitation is now unable to support human life will just lie down and die peacefully?
> We will adapt to whatever climate exists.
also, air conditioning and the netherlands are ways to deal with existing nature, global warming on the other hand is entirely man-made and compunding
[0] https://www.nytimes.com/2022/04/28/world/asia/india-extreme-...
It's of course a very urgent issue, but I think exaggerating it until it becomes a threat to "all life on earth" levels is a) dishonest b) does nothing to convince sceptics that it's a real issue, quite the opposite c) is not really all that actionable (at least not in a good way).