Mid-Pleistocene transition in glacial cycles explained by declining CO<sub>2</sub> and regolith removal.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 30949580.
- Also identified by DOI 10.1126/sciadv.aav7337 and PMC identifier 6447376.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Variations in Earth's orbit pace the glacial-interglacial cycles of the Quaternary, but the mechanisms that transform regional and seasonal variations in solar insolation into glacial-interglacial cycles are still elusive. Here, we present transient simulations of coevolution of climate, ice sheets, and carbon cycle over the past 3 million years. We show that a gradual lowering of atmospheric CO<sub>2</sub> and regolith removal are essential to reproduce the evolution of climate variability over the Quaternary. The long-term CO<sub>2</sub> decrease leads to the initiation of Northern Hemisphere glaciation and an increase in the amplitude of glacial-interglacial variations, while the combined effect of CO<sub>2</sub> decline and regolith removal controls the timing of the transition from a 41,000- to 100,000-year world. Our results suggest that the current CO<sub>2</sub> concentration is unprecedented over the past 3 million years and that global temperature never exceeded the preindustrial value by more than 2°C during the Quaternary.