Robust land surface temperature record for north China over the past 21,000 years

Area of Science:

• Paleoclimatology
• Quaternary geology
• Climate science

Background:

• Late Quaternary East Asian Monsoon variability is crucial for understanding regional climate dynamics.
• Previous proxy reconstructions offer general insights but struggle with precise absolute temperature assessments.
• Reconciling proxy data with climate model outputs remains a significant challenge.

Purpose of the Study:

• To establish a robust, high-resolution land surface temperature record for the past ~21,000 years in the western Chinese Loess Plateau.
• To independently validate temperature reconstructions using two distinct paleothermometers.
• To investigate discrepancies between paleoclimate proxy data and climate model predictions for the Holocene.

Main Methods:

• Utilized two independent paleothermometers: bacterial membrane lipids and clumped isotopes from fossil snail shells.
• Analyzed samples from a single stratigraphic section in the western Chinese Loess Plateau.
• Employed a land surface energy partitioning model to explore potential mechanisms.

Main Results:

• Developed a consistent land surface temperature record spanning the last ~21,000 years.
• Revealed comparable land surface temperatures between the Last Glacial Maximum and the late Holocene.
• Documented a gradual cooling trend throughout the Holocene, contrasting with climate model simulations.

Conclusions:

• Soil moisture availability during deglaciation significantly influences land surface temperatures recorded by proxies.
• Discrepancies between proxy data and climate models may arise from unaddressed soil moisture effects.
• Future paleoclimate studies should integrate soil moisture dynamics when comparing proxy reconstructions with climate model outputs.