Earth & Climate
Explainer
How Rocks Control Earth's Thermostat
Rocks slowly pull carbon dioxide out of the sky. Here's how.
Quick check · tap an answer to continue
Lesson notes
Key points
- Rainwater dissolves atmospheric carbon dioxide, forming weak carbonic acid that attacks silicate rocks like granite.
- This chemical weathering releases calcium and bicarbonate ions, which rivers carry to the ocean.
- In the ocean, organisms build calcium carbonate shells that settle and become limestone, locking carbon away.
- Warmer, wetter climates weather rock faster, drawing down more carbon dioxide, a negative feedback over millions of years.
Takeaway: Silicate weathering is Earth's slow, long-term carbon thermostat.
Quick check: How does a warmer climate affect silicate weathering rates?
- It speeds them up
- It slows them down
- It has no effect
Heat and rain accelerate reactions, removing more CO₂ and cooling Earth.
Carbonic acidChemical weatheringCarbon burialNegative feedback
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