Reconciling ice core CO<sub>2</sub> and land-use change following New World-Old World contact.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 38443398.
- Also identified by DOI 10.1038/s41467-024-45894-9 and PMC identifier 10915154.
- 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
Ice core records of carbon dioxide (CO<sub>2</sub>) throughout the last 2000 years provide context for the unprecedented anthropogenic rise in atmospheric CO<sub>2</sub> and insights into global carbon cycle dynamics. Yet the atmospheric history of CO<sub>2</sub> remains uncertain in some time intervals. Here we present measurements of CO<sub>2</sub> and methane (CH<sub>4</sub>) in the Skytrain ice core from 1450 to 1700 CE. Results suggest a sudden decrease in CO<sub>2</sub> around 1610 CE in one widely used record may be an artefact of a small number of anomalously low values. Our analysis supports a more gradual decrease in CO<sub>2</sub> of 0.5 ppm per decade from 1516 to 1670 CE, with an inferred land carbon sink of 2.6 PgC per decade. This corroborates modelled scenarios of large-scale reorganisation of land use in the Americas following New World-Old World contact, whereas a rapid decrease in CO<sub>2</sub> at 1610 CE is incompatible with even the most extreme land-use change scenarios.