Collaborative Research: P2C2 -- Connecting Common Era climate and sea level variability along the Eastern North American coastline

Sea level along the eastern North American coastline is rising faster than global sea level and is expected to accelerate dramatically over the 21st century. The uncertainty and societal impact of this acceleration underscores the need for an improved understanding of relationships between regional sea level and climate. High-resolution sea level proxies spanning the past ~2,000 years (the 'Common Era') reveal century-scale, decimeter-amplitude (up to ~20-cm), variability along the east coast associated with changes in dynamic sea level (DSL). These changes offer a unique benchmark for climate models, and the closest observational analog for climate-driven sea level change expected in the 21st century. This project will employ statistical and dynamical models to improve the scientific understanding of Common Era sea level changes along the east coast and their relationship with climate. The research team will leverage this knowledge to inform projections of 21st century DSL change and the ability of current-generation climate models to capture those changes, in turn informing coastal resilience efforts along the high-risk eastern North American coast. The project will provide funding and opportunities for an early career scientist and a graduate student to develop a diverse set of skills and collaborators in paleoclimate, climate modeling, and weather and climate risk assessment.

The project team will confront the sparsity of the proxy record and the limitations of current-generation paleoclimate simulations by testing hypotheses about the drivers of sea level variability using a broad statistically- and dynamically-based modeling strategy. Project tasks include: (1) a rigorous assessment of the robustness of regional DSL reconstructions generated with a hierarchical spatio-temporal statistical framework; (2) leveraging the statistical framework to assess linkages between DSL and other climate indices (e.g., North Atlantic Oscillation, Atlantic Meridional Overturning Circulation, sea surface temperature and salinity, Intertropical Convergence Zone position); and (3) conducting and analyzing coupled climate model simulations. Climate model simulations will be forced by proxy-derived surface fluxes and validated by a synthesis of complementary climate reconstructions. The simulations will reveal the dynamical mechanisms underlying correlations found in reconstructions and demonstrate whether relationships observed in the instrumental record persist over multidecadal-to-centennial timescales. The research is expected to lead to a more complete interpretation of Common Era sea level and climate variability.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.