Quantifying global aridity of the Late Quaternary from closed-basin lakes

Quantifying the magnitude and timing of hydroclimatic changes throughout Earth’s history is central to determining Earth’s hydrological sensitivity. Here, we present a novel method for quantifying hydroclimatic changes during the Late Quaternary using evidence from a global database of changes in lake sizes of closed-basin lakes. Closed-basin (or endorheic) lakes provide a powerful yet underutilized archive of past hydroclimatic conditions during periods of increased effective moisture.

We reconstructed hydroclimatic conditions over the past ~25,000 years across a global dataset of closed-basin lakes using the Budyko–Fu water-balance model, modern climate data, independent paleo-temperature reconstructions, and an advanced evaporation model corrected for changes in lake salinity. This quantitative reconstruction of both precipitation and evaporation enables us to reconstruct the magnitudes and spatial evolution of the dominant atmospheric circulation systems worldwide.

Our results reveal coherent regional hydroclimate patterns in both the extent and direction of circulation changes. In western North America, the moisture track was shifted ~600 km SW in the Early Holocene, and ~900 km NW in the Late Holocene, relative to the present climate. In western Central Asia, the westerlies-dominated region was shifted ~900 km NNE during the Deglacial period and ~1100 km NW during the Late Holocene. The East Asian monsoon expanded ~300 km W-NW during the Early and Late Holocene. The African monsoon expanded ~750 km NE in the Early Holocene. Using these results, we quantify the extent of global desertification that occurred since the last glacial period. This quantitative paleo-hydroclimatic reconstruction demonstrates the potential of closed-basin lakes to constrain past atmospheric circulation dynamics and provides a robust benchmark for ground-truthing global climate models.