Tropical temperature evolution across two glacial cycles derived from speleothem fluid inclusion microthermometry

A new study reveals that tropical temperatures in Northern Borneo, specifically within Gunung Mulu National Park, closely tracked Southern Hemisphere temperatures and atmospheric CO₂ concentrations over two glacial cycles. Using speleothem fluid inclusion microthermometry—a highly precise method based on the density of trapped water—the research reconstructed cave temperatures spanning 127,000 years, from 460 to 333 thousand years ago. The findings indicate that deglacial warming in this region was accompanied by relatively dry conditions, with temperature changes reaching amplitudes of up to 4.3°C between glacial and interglacial periods. Notably, the study also identifies a site-specific Antarctic amplification factor, suggesting stronger polar temperature responses compared to tropical regions.

Krüger, Y., Pasqualetto, L., Fernandez, A., Cobb, K. M., & Meckler, A. N. (2025). Tropical temperature evolution across two glacial cycles derived from speleothem fluid inclusion microthermometry. Climate of the Past, 21(9), 1553–1584. https://doi.org/10.5194/cp-21-1553-2025