Abstract
Marine Isotope Stage (MIS) 5c, between ~106,000 and
~93,000 years ago, represents an important warm period
on Earth in which the current anthropogenic warming can be
contextualized. Although viewed as a pronounced interstadial, its
climate expression is regionally disparate, with different regions on
Earth showing evidence of either cooler conditions than modern-day or
warmer conditions than modern-day. It is therefore important to expand
temperature reconstructions to different regions on Earth to gain a
better picture of climate dynamics during MIS 5c. In Alaska, there are
no quantitative temperature reconstructions for MIS 5c, vastly limiting
our knowledge of temperature changes in this climatically sensitive
high-latitude region. Here, we fill-in this gap by providing the first
quantitative temperatures from MIS 5c in Alaska using hydrogen isotopes
from fluid inclusions in precisely dated speleothems. We find that
regional temperatures during MIS 5c were within error of modern-day
(2021 CE) temperatures, likely representing the most recent time period
that regional temperatures were as high as modern-day.