Tectonic plates, not volcanoes, drove Earth's climate shifts: Study
Turns out, it wasn't just volcanoes shaping Earth's climate—tectonic plates moving apart at mid-ocean ridges and rifts had a much bigger impact on carbon dioxide levels through much of the last 540 million years, although volcanic arcs became the dominant carbon source in the last ~120 million years (linked to the rise and spread of planktic calcifiers).
How scientists figured this out
Researchers used computer models to trace how carbon moved between Earth's interior, oceans, and air.
They found that when more carbon escaped than got trapped, global warming kicked in. But when most carbon settled into ocean sediments, the planet cooled down.
Why it matters now
Volcanoes only became big CO2 players in the last 120 million years.
Today, humans are adding carbon to the atmosphere, rapidly increasing CO2 levels—which is a wake-up call for how quickly we're changing the planet's climate.