Wipe out 90% of the population and we're back to what, the 1800s? That level of death requires most people to just let the rising ocean drown them as they stand there plus a bunch more inland to walk in and drown themselves as well.
Massively distruption to the status quo is what climate change will bring. Civilization ending? Not even close.
But our civilization as we know it may very well collapse. Yes some sort of civilization will continue to exist. But this will be on par with the dark ages: not a complete destruction of human civilization but an enormous regression.
We will most likely loose a lot of our technological know-how and abilities. Events like this don't simply cause a gradual decline in standards of living. Rather they tend to cause massive outbreaks of wars, unrest, migrations, refugees, destruction etc.
Climate change in the bronze age caused nearly all major bronze age civilizations to collapse. But with this collapse we had major migration of people, wars, invasions, collapse of trade and many more things. What followed was large population declines as well as losing the ability to write and maintain organized rule, construct buildings etc.
Did all humans disappear? Of course not, that is why civilization reappeared again eventually at a later time. The same will likely happen with us. But how long will the dark ages last?
In many ways our resilience is weaker than theirs. Our trade networks are far more extensive and important than the ancient ones. What happens e.g. if the middle east, Africa and South America are turned into turmoil and we can no longer get resources extracted from either of those places?
Our economies may suffer a lot too, causing the breakout of widespread riots and unrest, overthrow of governments. If modern trade breaks down, there will be widespread famines even in the west, because many countries simply are not self sufficient. And if they are, their food production depends on a large number of imports. If they don't get hold of artificial fertilizer, fuel etc food production will collapse.
This is what we saw after the fall or Rome. Economies became far more regionalized/local. In a collapsing world economy, countries will become significantly poorer if forced to rely exclusively on local production of most essential things.
1. Except without access to easily accessible sources of oil, minerals, and energy.
2. If you think that rising sea levels are the problem [1] with climate change, I'm not sure you understand it, at all. This seriously undermines your points. The actual threat is disruption of agriculture, and ocean ecosystem collapse.