[sci_prog]

You are right, Earth does have mechanisms through which it regulates the CO2 and tries to bring it back to "balance". But it is important to note that these mechanics (e.g. increased in weathering) take 10s-100s of thousands of years to take effect.

[lmilcin]

There are faster, more responsive mechanism that actually saved us from most of the problem for past decades. CO2 gets dissolved in ocean water very efficiently causing acidification and getting into other reactions.

Unfortunately, it seems oceans are loosing their ability to buffer CO2 and this may cause sharper increase in atmospheric CO2.

[refurb]

The earth doesn’t “regulate” CO2. CO2 levels have been much higher in the past. There are natural process which just happen to capture or release CO2, but there is no “right” level of CO2.