Orbitally driven changes in seasonal Antarctic temperature during the Holocene [post]

Tyler Jones, Bradley Markle, William Roberts, Kurt Cuffey, Eric Steig, Christopher Stevens, Paul Valdes, T.J. Fudge, Michael Sigl, Abigail Hughes, Joshua Garland, Bo Vinther (+3 others)
2021 unpublished
Disentangling the drivers of mean annual temperature change in Antarctica requires an understanding of seasonal temperature change. A high-resolution climate record capable of resolving summer and winter seasons could address long-standing questions about the role of orbitally-driven insolation in driving Antarctic mean-annual temperature change. Here, we present a continuous record of water isotope ratios from the West Antarctic Ice Sheet (WAIS) Divide ice core that reveals both summer and
more » ... both summer and winter temperature change though the last 11,000 years. This novel record shows that summer temperatures increased through the early-to-mid Holocene, reached a plateau at 4 to 2 ka, and then decreased to the present. The observed changes are explained primarily by changes in maximum summer insolation. In the early to mid-Holocene, additional summer warming results from the retreat and thinning of the WAIS. The magnitude of summer temperature change constrains the lowering of the WAIS surface to less than 100 m since the early Holocene, consistent with geologic records. Importantly, annual mean temperatures cannot be fully explained by orbital forcing and ice sheet elevation change alone; in the early Holocene, large wintertime temperature excursions overwhelm the summer signal. These winter excursions indicate that regional heat transport anomalies, rather than local thermodynamics, can dominate the annual mean.
doi:10.21203/rs.3.rs-564788/v1 fatcat:6ll74vs5erfindpm4ywaqgasoe