I don't care if it is caused by humans or natural causes ( and it's likely both). The issue is that it's a problem, because we've evolved to live in a cool environment (relative to wherever this is going). Part of responsibly using this planet we find ourselves on is terraforming it to sustainably and efficiently suit our needs. I support decarbonization because it helps. But due to other natural factors effecting our environment for the worse (as far as we as a species are concerned), we will need to take more artificial measures to cool the planet in the future.
But the first step is decarbonization. We have two choices - accept natural inefficiencies and extreme conditions, and slowly lose our intelligence in exchange for resilience (evolutionary "crabification"), or terraform the planet to a constant, efficient environment to continue developing as an intelligence.
We are caught, environmentally, in a neutral zone between extreme fluctuations that will continue until the earth cools entirely from its formation. We did not exist during the last extreme. And if we do not prevent the next, our species will not survive.