Asymmetric Cooling of the Atlantic and Pacific Arctic During the Past Two Millennia: A Dual Observation‐Modeling Study

Abstract

AbstractThe past 2,000 years provide a critical context for understanding twentieth century climate change. Due to the Past Global Changes 2k initiative, an extensive proxy database provides opportunities to assess regional climate change that have stronger ecological and societal implications than global‐mean temperature changes alone. However, the various sources of paleoclimate reconstruction poses serious challenges to scientifically and statistically sound inference within a unified framework. Here we show results from the first transient simulation for the past 2,000 years with the Community Earth System Model, called past2k, and use data‐model comparison to refine the interpretation of the proxy data. Our results indicate that the Atlantic Arctic was cooling at a faster rate than the Pacific Arctic over the past two millennia, in both proxy data and models. The model shows that this cooling pattern was dynamically supported by both a weakening of North Atlantic subpolar gyre and a stronger Aleutian Low.