Phanerozoic icehouse climates as the result of multiple solid-Earth cooling mechanisms.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 39951538.
- Also identified by DOI 10.1126/sciadv.adm9798 and PMC identifier 11827867.
- 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
The Phanerozoic climate has been interrupted by two long "icehouse" intervals, including the current icehouse of the last ~34 million years. While these cool intervals correspond to lower atmospheric CO<sub>2</sub>, it is unclear why CO<sub>2</sub> levels fell, with hypotheses suggesting changes in CO<sub>2</sub> degassing rates or modification of silicate weathering through changing continental lithology or paleogeography. Here, we construct an Earth System Model that integrates these proposed cooling mechanisms in detail. The model can reproduce the broad geologic record of ice cap expansion, allowing us to infer the primary drivers of long-term climate change. Our results indicate that recent icehouse climates required a combination of different cooling mechanisms acting simultaneously and were not driven by a single known process, potentially explaining why icehouses have been rarer than greenhouses over Earth history.