Mitigation is always possible. If we don’t do it intentionally, eventually the climate will force our hand. This will result in billions of human deaths, extinction of many organisms, and massive destruction of the current global ecology, but it will happen.
Remember, the Sahara wasn’t always a desert, and North America was more than once covered in ice.
We’re likely to die off due to poisoning the environment long before the climate makes a significant dent in our 8bn population.
We’re not going to escape sea level rise or some places becoming uninhabitable, nor a redistribution of water and total destruction of all weather models. But we can slow the changes to the point where we can adapt faster than the climate changes… and the more we mitigate, the more lives we save along the way.
They said your statement was incorrect; either there’s a way to salvage the planet in a habitable form, or there isn’t — but “indistinguishable from magic” doesn’t come into it.
Personally, I think energy is only a portion of the problem space; we need to slow climate change enough that humanity can continue to adapt with it.
After all, we survived multiple ice ages; will the climate destroy our technological advances, or will those advances enable us to adapt to a changing world?
The world is likely highly overpopulated at the present, but we can lose a significant chunk of humanity and still preserve the body of knowledge and many of the technologies that we currently enjoy.
Collapses are inevitable, but total collapse is still avoidable.