The Earth's Climate Can Change Rapidly!

This was proposed by Mihail Budyko in around 1969.
The evidence for it was compiled by Paul Hoffman in the mid 80s.
Back about 770 million year ago the Sun would have been around 7% weaker than today so it was much easier for the Earth to swing in and out of "ice ball" conditions, that is when ice sheets and sea ice were far at low enough latitudes to trigger a near planet wide glaciation. While the planet was cover with ice there was likely less rock weathering, this would have reduced the rate CO2 was scrubbed from the atmosphere so it built up. The theory goes this built enough to create a strong enough greenhouse effect to flip back into "hot house" conditions. This very warm, CO2 rich environment sees rock weathering go into over drive and leave deposits of cap carbonate.
https://en.wikipedia.org/wiki/Cap_carbonate

We have a much stronger Sun and a strengthening greenhouse effect so are very very unlikely to see another "ice house" in the coming centuries.