A 13,500 year speleothem record from southeastern Alaska

Under Anthropocene warming, Alaska is one of the fastest warming regions on Earth. To place this warming in better context, it is important to extend a high-resolution paleoclimate record throughout the Holocene. However, few such records exist in Alaska, with the majority limited to low-resolution lake sediment studies. Here, we provide a continuous, precisely dated, and high-resolution speleothem record that extends from modern-day to 13,500 yr BP. This represents the first Holocene speleothem record from Alaska, and sheds light on important paleoclimate changes at this high-latitude location. We find that the speleothem oxygen isotope record is largely controlled by changes in the tropical Pacific Ocean, with a significant mean state shift change occurring after ~1970 CE. The mean state shift at ~1970 CE has no similar anolog during the 13,500 year speleothem record, and we attribute the shift to anthropogenic forcing.