Year: 2025
Type: article
Abstract: The carbon isotopic composition of pedogenic carbonate (δ 13 C c ) is a widely used proxy for paleoatmospheric CO 2 levels. However, the estimated CO 2 is often highly uncertain due to the lack of constraints on other variables that influence this system. To improve paleosol‐based CO 2 reconstructions, here we propose the Joint Proxy Inversion (JPI) of a paleosol‐based proxy system model, which integrates various proxies (e.g., pedogenic carbonate δ 13 C and δ 18 O) that share sensitivities to common environmental parameters (e.g., CO 2 , precipitation) via a forward proxy model in a Bayesian hierarchical framework. JPI generates self‐consistent posterior distributions of environmental parameters conditioned on multi‐proxy data sets while accounting for proxy and model uncertainties. The JPI was applied to data from Quaternary loess deposits from the Chinese Loess Plateau to test its performance. Sensitivity tests and posterior CO 2 estimates suggest insensitivity of proxy values to CO 2 when the analysis integrates δ 13 C, δ 18 O c , and clumped isotope values of pedogenic carbonates only. Improved results were achieved after incorporating a precipitation‐sensitive proxy, a model component representing environmental variation as a function of time, and a parameterized relationship between global temperature and CO 2 . The improved model performance is indicated by agreement between posteriors of environmental parameters (i.e., CO 2 , temperature, precipitation) and other independent records. Compared to the traditional proxy interpretation approach, the paleosol‐JPI offers a more holistic and rigorous way to interpret multi‐proxy records with shared environmental sensitivities, provides additional information on climate and environmental systems, and is capable of reconstructing paleo‐CO 2 levels with higher precision and fidelity.
DOI: 10.1029/2025pa005317
Language: English
Subfield: Atmospheric Science
Field: Earth and Planetary Sciences
Domain: Physical Sciences
SDG: Climate action
Open Access status: hybrid
Estimated APC paid: $4,070
Awards: Acquisition of a clumped isotope gas-source isotope-ratio mass spectrometer and carbonate device for inclusive research and education at the University of Washington, Collaborative Prop: CO2PIP-A Community Project to advance and standardize approaches to paleo-CO2 reconstruction and to build the next-generation Phanerozoic record, Collaborative Proposal: CO2PIP — A Community Project to advance and standardize approaches to paleo-CO2 reconstruction and build the next-generation Phanerozoic record, G610850304, Collaborative Proposal: CO2PIP — A Community Project to advance and standardize approaches to paleo-CO2 reconstruction and build the next-generation Phanerozoic record
OpenAlex ID: W4416540310