Resolving discrepancies between climate model simulations and proxy records of long-term terrestrial hydroclimate and temperature trends is crucial for improving future climate projections. However, the origin of these mismatches remains debated. They may stem from potential seasonality biases in proxy reconstructions and/or inaccurate parameterization of climate sensitivity in models. This session invites contributions aiming to advance paleoclimate modeling and proxy interpretation through improved geochemical methods (eg, isotopes, pollen, organic biomarkers), integration of expanded climate and ecological parameters (such as dynamic ice sheets and vegetation) into models, and combination of high-resolution proxy reconstructions from geological archives (eg, speleothems, lake and marine sediments) with climate simulations across interannual to precessional timescales. We encourage studies that include machine-learning approaches to enhance data interpretation.