侏罗纪高分辨率大气二氧化碳浓度变化:来自C3植物有机碳同位素的证据OA

The increase in atmospheric carbon dioxide(pCO2)concentration is widely recognized as the primary driver of global warming.Reconstructing pCO2 levels during geological periods is crucial for improving predictions of future climate change.The Jurassic period represents a typical greenhouse climate interval in Earth's history.Previous studies have estimated Jurassic pCO2 concentrations using various approaches,including climate simulations and geological proxies.However,existing reconstructions are characterized by low temporal resolution and significant discrepancies among different proxy records.In this study,we systematically compiled 1808 C3 plant organic carbon isotope data points from the Jurassic period and applied a novel pCO2 proxy-based on C3 terrestrial plant organic carbon isotopes-to reconstruct a high-resolution,continuous record of atmospheric pCO2 variation throughout the period.Our results indicate that pCO2 levels ranged from 407×10-6 to 7540×10-6,which is broadly consistent with prior estimates.Furthermore,pCO2 exhibited an overall decreasing trend punctuated by three distinct intervals of elevated concentrations,occurring in the Early and Late Jurassic.These fluctuations correlate strongly with coeval geological events,supporting the reliability of the reconstruction.Although the reconstructed pCO2 values during the Early Jurassic Toarcian stage are higher than those derived from other proxies-likely due to regional influences on the isotopic composition of terrestrial C3 plants-the dataset still accurately captures the long-term variation trend of pCO2,underscoring its scientific value.