Your Life as Planet Earth

A new way to understand the story of the Earth, its climate and our origins

Slow vs. Fast climate changes

Slow changes

How oceans processed the slow glacial-interglacial changes in the ice ages. CCD = Carbonate Compensation Depth, CO32- = carbonate. Based on text in Zeebe, Annual Reviews 2012.

The orbitally-induced glacial-interglacial cycles of the last ice age happened slowly enough that the long-term feedbacks of Earth’s climate system had time to process them. In warmer interglacials, more intense insolation in northern hemisphere summers led to warmer oceans which were in equilibrium with slightly more CO2 in the atmosphere by adjusting their carbonate levels. In glacial times with less intense northern hemisphere summer insolation, the cooler oceans dissolved more CO2, and carbonate levels adjusted accordingly. The changes occurred over gentle timescales of tens of thousands to hundreds of thousands of years – plenty slow enough for slow feedbacks like the deep oceans and ice sheets to keep pace.

Fast changes

How oceans get overwhelmed by rapid large CO2 emissions from Large Igneous Province (LIP) eruptions and human emissions. CH4 = methane, CCD = Carbonate Compensation Depth, CO32- = carbonate. Based on text in Zeebe, Annual Reviews 2012.

Rapid carbon belches from LIP eruptions (and humans), occur within the timeframe of fast feedbacks (surface ocean, water vapor, clouds, dust, biospherelapse rate, etc.) but before the vast deep ocean reservoir and rock weathering can cut-in to buffer the changes. The carbon overwhelms the surface ocean and biosphere reservoirs so it has nowhere to go but the atmosphere, where it builds up rapidly, creating strong global warming via the greenhouse effect. The surface oceans turn acidic as they become increasingly saturated in CO2The oceans warm, so sea levels rise.