LAUSR

The Paleocene‐Eocene Thermal Maximum (PETM; ∼56 Ma)–a geologically rapid carbon‐release event similar to anthropogenic carbon emissions–is ideal for investigating weathering responses to rapid carbon release and associated climate change. Here, for the first time, we present high‐resolution lacustrine lithium isotope data that reflect basin‐scale silicate weathering across the PETM in the Nanyang Basin, eastern China. Our results reveal an ∼100% increase in regional silicate weathering intensity through the PETM relative to the pre‐PETM level. Synchronous variations between carbon isotope values and weathering intensity demonstrate a strong coupling between carbon cycle, climate, and chemical weathering on millennial timescales. These findings argue that strong negative weathering feedback and massive removal of CO2 maintained Earth's climate within a habitable range during the PETM.