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

The 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-meantemperature changes alone. However, the various sources of paleoclimate reconstruction poses serious challenges to scienti fically and statistically sound inference within a uni fied 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 re fine the interpretation of the proxy data. Our results indicate that the Atlantic Arctic was cooling at a faster rate than the Paci fic Arctic over the past two millennia, in both