At times in the past, mobile ocean fronts in the subtropics have exercised an influence on the magnitude of climate change by decoupling temperature from levels of carbon dioxide in the atmosphere.

Galactic cosmic rays could influence Earth's cloudiness by creating aerosol particles that prompt cloud formation. That possible effect looks to be smaller than thought, but the story won't end there.

Atmospheric aerosols (a mixture of solid or liquid particles suspended in the air medium) are short-lived, with a residence time of about a week in the lower troposphere. Unlike the principal greenhouse gases, aerosols are more concentrated in the source regions and exhibit strong spatial and temporal variations.

Environmental conditions during the past 24 million years are thought to have been favourable for enhanced rates of atmospheric carbon dioxide drawdown by silicate chemical weathering. Proxy records indicate, however, that the Earth's atmospheric carbon dioxide concentrations did not fall below about 200

Levels of atmospheric carbon dioxide constrain vegetation types and thus also non-biological uptake during rock weathering. That's the reasoning used to explain why CO2 levels did not fall below a certain point in the Miocene.

The dominant period of Pleistocene glacial cycles changed during the mid-Pleistocene from 40,000 years to 100,000 years, for as yet unknown reasons.