<p>The study of past climate trends, variability, and extremes has yielded unique insights into Earth&#8217;s changing climate, yet paleoclimate science must overcome a number of key challenges to maximize its utility in a century defined by accelerating climate change. First, the paleoclimate archive itself is at grave risk, given that i) many records end in the late 20<sup>th</sup> century, and no concerted efforts exist to extend them to the present-day, and ii) many paleoclimate archives are disappearing under continued climate change and other forms of human disturbance. Second, many paleoclimate records are comprised of oxygen isotopes, yet the coordinated, multi-scale observational and modeling infrastructures required to unravel the mechanisms governing water isotope variability are as yet underdeveloped. Lastly, in part owing to the aforementioned deficiencies, paleoclimate data assimilation efforts remain fraught with large uncertainties, despite their promise in constraining many aspects of future climate impacts, including extreme events and hydrological trends and variability. Paleoclimate science for the 21<sup>st</sup> century requires deep investments in the full integration of paleoclimate data and approaches into frameworks for climate risk and hazard assessments. In that sense, paleoclimate scientists will continue to play a key role in the communication of climate change science to key stakeholders, including the general public. Their understanding of the Earth system also equips them to contribute valuable insights to teams comprised of researchers, practitioners, and&#160; decision-makers charged with leveraging science to inform solutions, in service to society.</p>
Review of of "Multi-Scale Sea Ice Kinematics Modeling with a Grid Hierarchy in Community Earth System Model (version 1.2.1)"