CO2PIP Consortium for Advancing paleo-CO2 reconstruction and Building the Next-Generation Phanerozoic CO2 Record

Paleo-CO₂ reconstructions are integral to understanding the evolution of Earth system processes and their interactions given that atmospheric CO₂ concentrations are intrinsically linked to planetary function. Furthermore, past periods of major climate change provide unique insights into the response of land-atmosphere-ocean interactions to warming-induced climate change, particularly for times of pCO₂ comparable to those projected for our future. How well the past can inform the future, however, depends on how well paleo-CO₂ estimates areconstrained. CO₂ estimates exist for much of the past half-billion years (the Phanerozoic), but proxies differ in their assumptions and degree of understanding, and there is substantial uncertainty and inconsistency in existing paleo-CO₂ estimates. Here, we introduce a community initiative, CO₂PIP, focused on advancing the science of paleo-CO₂ reconstruction through critically evaluating and modernizing existing records and building a statistically robust multi-proxy atmospheric CO₂ record for the Phanerozoic. CO₂PIP builds on the previous work of the Cenozoic CO₂ Proxy Integration Project (CenCO₂PIP) Consortium (Hönisch et al., 2023) and takes a multi-step approach to building the next generation Phanerozoic CO₂ record. We are building a standardized paleo-CO₂ proxy data repository that includes all metadata and updated chronology and meets FAIR (findable, accessible, interoperable, reusable) data standards. Existing terrestrial-based CO₂ estimates are being modernized through additional analyses and measurements, and a set of forward proxy system models are being developed to provide a quantified representation of proxy sensitivities to environmental and ecophysiological conditions and processes that govern the CO₂ signals. Ultimately, statistical inversion analysis of the simulated and modernized proxy datasets will be used to produce quantitative, data-driven CO₂ reconstructions for individual records and to generate a robust, quantitative reconstruction of atmospheric CO₂ concentrations through the Phanerozoic. Digital infrastructure for presenting and archiving the CO₂ compilation and project outputs (https://paleo-co2.org/) ensures full accessibility to the scientific community and the public.

Hönisch, B. Royer, D., Breecker, D. O., et al., 2023, Towards a Cenozoic history of atmospheric CO₂. Science, v. 382 (6675), DOI: 10.1126/science.adi5177).