Continental water recycling and H₂¹⁸O concentrations

Using a GCM fitted with tracer diagnostics, we examine how continental moisture recycling affects the stable water isotope content of precipitation, focusing on its contribution to the “noise” in the well‐established relationship between temperature and δ 18 O. On a global basis, for temperatures between −30° and 15°C, continental recycling explains more than a third of the variability in annual δ 18 O that is not explained by temperature. Recycling appears almost as important as temperature in defining δ 18 O distributions during northern hemisphere summer.