I was [reading initially about](https://www.climate.gov/news-features/climate-qa/whats-hottest-earths-ever-been) global temperature characteristics throughout the ages, trying to understand what things are going to look like, what might happen, etc.
CO2 levels are referred to in the article and mentions
So I looked up more information on silicate rock and it’s relationship with CO2 and found this [article](https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2020EF001938)
So basically, silicate rock removes CO2 from circulation and repurposes it to something else?
In: Planetary Science
Not quite. It takes CO2 out of rain.
CO2 in the air combines with clouds to form carbonic acid (H2CO3) in the rainwater. This is the main reason why rainwater tends to be mildly acidic.
That carbonic acid reacts with silicate rocks to produce dissolved silica, some bicarbonate, and other ions depending on the actual nature of the silicate rock (Mg+ and Ca+ are common ones; calcium in particular is important to this cycle).
The dissolved calcium and bicarbonate get washed away, wind up in a river, which slowly winds up in the ocean. Marine animals grab that stuff out of the water and use it to make shells. Then they die, and their shells get compressed into limestone, which is often then subsumed under the crust.
Once under the crust, it churns around for a while, gets hot, and creates pockets of CO2 which eventually escape via geysers, volcanos, hot springs, etc.
The rate of all these various interactions produces something of a buffer which regulates the amount of CO2 in the atmosphere over very, very long time periods.
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