Warming‐Induced Atmospheric Drying in Eastern China Since 1955: Evidence From Tree‐Ring Stable Carbon and Oxygen Isotopes

The vapor pressure deficit (VPD), defined as the difference between saturated and actual water vapor pressure, is a key determinant of atmospheric evaporative demand and a critical regulator of terrestrial carbon cycles. Understanding how rising temperatures influence VPD dynamics is therefore crucial in the context of global warming. In this study, we reconstructed April–August VPD variability from 1864 to 2022 using a composite tree‐ring stable carbon (δ 13 C) and oxygen (δ 18 O) isotope chronology derived from Chinese pine ( Pinus tabuliformis ) in Eastern China, a typical monsoon region. Our reconstruction shows that VPD from 1864 to 2022 has generally increased, and the drying trend is more significant since 1955. This accelerated VPD rise is attributed to both increasing temperature and decreasing precipitation, with temperature being the dominant driver. Future projections from the IPSL‐CM6A‐LR model, validated against our reconstruction, point to a marked and sustained increase in VPD across all four scenarios over the next century, thereby constituting a fundamental threat to regional ecosystems.