Global analysis reveals climatic controls on the oxygen isotope composition of cave drip water

δ18O of speleothems are a widely used paleoclimate proxy. Here, the authors conduct a global analysis of cave drip water δ18O compositions and find that drip waters from warmer climates have a seasonal bias toward precipitation δ18O of recharge periods, unlike in cooler climates where drip waters match well with recharge-weighted δ18O.