Oxygen Isotopes in Tree Rings Track Neotropical Climate Dynamics

Abstract Central America faces increasing risks from climate variability and extreme weather events. Limited observational records and model biases have constrained our ability to understand the ocean–atmosphere dynamics that influence precipitation variability in the region over longer timescales. Paleoclimate proxies, including the stable oxygen isotope ratio of the cellulose of tropical trees, can extend the climate record, allowing recent trends and variability to be evaluated in a long‐term context and improving our understanding of forced and unforced variability of the climate system. Here, we present a new multidecadal record of tree‐ring from Abies guatemalensis (Guatemalan Fir) from Guatemala and Honduras. We demonstrate that this proxy records boreal summer rainfall and is tightly coupled to neotropical ocean–atmosphere dynamics. This precisely dated, high‐resolution proxy can be used for multicentury hydroclimate reconstructions of the Intertropical Convergence Zone dynamics and its interactions with the eastern Pacific Ocean and Caribbean Sea.