Borneo caves as climate recorders: the last interglacial to today

Kim and Jessica Moerman in Cobweb Cave, Gunung Mulu National Park, Sarawak, Malaysia. During expeditions, we collect rainwaters, dripwaters, and fallen stalagmites in an effort to understand how climate of the past and present is reflected in cave stalagmites.
Baby stalagmites growing in Clearwater Cave at Gunung Mulu National Park. We have placed a growth plate on the top of the formation so that we can collect the newest calcite growth that accretes over the next years for geochemical analyses.
Johnny Baei Hassan, a Sarawak Forestry guide, the best climber I’ve ever met, and saver of scientist’s lives, looking out from the entrance to Mojo cave at Gunung Buda National Park, 100m off the floor of the rainforest.
From left: Stacy Carolin, Kim Cobb, Jud Partin, Syria Lejau, and Nele Meckler. We are waiting to board the canoe for the day-long trip to the remote Camp 5.
The dearth of high-resolution, well-dated records of tropical Pacific climate over the last glacial cycle leaves many key questions about the mechanisms of global climate change unanswered. This is particularly true for the repeated abrupt climate change events that are scattered throughout the last glacial period. Such events profoundly reshaped global climate patterns over a period of decades to centuries, yet their underlying causes and feedbacks remain uncertain.

Over the last ten years, my group has pursued new records of glacial-interglacial climate variability using stalagmites from caves in Borneo. We use the oxygen isotopic composition (δ18O) of the stalagmite calcite as a proxy for regional hydrology, as supported by our on-site calibration efforts. Thanks to collaborator Jess Adkins at Caltech, our timeseries of stalagmite oxygen isotope variability are exceptionally well-dated using Uranium-Thorium dating methods. By combining several overlapping stalagmite δ18O records from the same site, we highlight shared features most likely caused by regional climate changes.

Some highlights from our cave stalagmite publications:

  • identified a strong drying in Borneo associated with the Heinrich 1 abrupt climate change event originally described in the North Atlantic, consistent with climate model simulations; isolated a spring/fall precessional control on northern Warm Pool hydroclimate over the last 30,000yrs. Take-home: Warm Pool hydrology is very sensitive to some, though not all, of the high-latitude climate forcing thought to dominate abrupt climate change events (Partin et al., 2007)
  • reconstructed cave stalagmite δ18O through a known high-latitude climate transition that took place 450,000yrs ago, resolving 3 major glacial-interglacial cycles in the process; uncovered strong inferred drying events similar to Heinrich 1 drying, but found little correspondence between major high-latitude climate shift and western tropical Pacific hydroclimate (Meckler et al., 2012)

Publications

Carolin, S.*, K.M. Cobb, J.F. Adkins, B. Clark, A. Tuen. Varied response of western tropical Pacific hydrology to abrupt climate changes. Revised for Science.

Moerman, J.W.*, K.M. Cobb, J.F. Adkins, H. Sodemann, B. Clark, A. Tuen, Large-scale climate controls on rainfall oxygen isotope variability in the west Pacific Warm Pool. Revised for EPSL.

Meckler, A., M. Clarkson, K.M. Cobb, J. Eiler, H. Sodemann, J.F. Adkins. Interglacial hydroclimate in the tropical West Pacific through the late Pleistocene, Science 336: 1301-1304, 2012.

Partin, J.W.*, K.M. Cobb, J.F. Adkins, B. Clark, D.P. Fernandez. Millennial-scale trends in west Pacific warm pool hydrology since the Last Glacial Maximum. Nature 449: 452-455, 2007.

Cobb, K.M., B. Clark , J.W. Partin, J.F. Adkins. Regional-scale climate influences on temporal variations in rainwater and cave dripwater oxygen isotopes in northern Borneo. Earth and Planetary Science Letters 263: 207-220, 2007.

Presentations

Stalagmite records of abrupt climate change in the tropical Pacific (40 min) UGA, Sept 11, 2008.

People

Collaborators

Funding Sources

Other

  • Niko Sluzki, field videography