Chasing Interannual Marine Paleovariability

Several modes of tropical sea-surface temperature (SST) variability operate on year-to-year (interannual) timescales and profoundly shape seasonal precipitation patterns across adjacent landmasses. Substantial uncertainty remains in addressing how SST variability will become altered under sustained greenhouse warming. Paleoceanographic estimates of changes in variability under past climatic states have emerged as a powerful method to clarify the sensitivity of interannual variability to climate forcing. Several approaches have been developed to investigate interannual SST variability within and beyond the observational period, primarily using marine calcifiers that afford subannual-resolution sampling plans. Amongst these approaches, geochemical variations in coral skeletons are particularly attractive for their near-monthly, continuous sampling resolution, and capacity to focus on SST anomalies after removing an annual cycle calculated over many years (represented as geochemical oscillations). Here we briefly review the paleoceanographic pursuit of interannual variability. We additionally highlight recent research documented by Ong et al., (2022, https://doi.org/10.1029/2022PA004483) who demonstrate the utility of Sr/Ca variations in capturing SST variability using a difficult-to-sample meandroid coral species, Colpophyllia natans, which is widespread across the Caribbean region and can be used to generate records spanning multiple centuries.