Stalagmites in Borneo Reveal 100,000 Years' Worth of Climate Data

An in-depth study of mineral samples in stalagmites reports that over tens of thousands of years, the western tropical Pacific responded to abrupt climate change events differently than other regions of the world, a find that scientists say will help provide a better understanding of climate change throughout the course or Earth's history.

In three separate caves in northern Borneo, researchers analyzed oxygen isotopes from more than 1,700 stalagmites. Stalagmites act as time capsules, holding entire eras' worth climate data. While scientist have instrumental records of about a century's worth of climate data, they must turn to the geological record to gain further insight into the history of climate change on Earth.

The results of the study suggest that "climate feedbacks within the tropical regions may amplify and prolong abrupt climate change events that were first discovered in the North Atlantic," according to a news release from Georgia Institute of Technology.

Kim Cobb, from the school's department of Earth and atmospheric sciences, says the research provides a piece of the puzzle that shows how the climate system in the tropical Pacific have responded to climate events over the past 100,000 years.

Cob was surprised to find that the stalagmite record in Borneo's caves was differnet than caves in other regions not far away. The Borneo stalagmite record revealed evidence of Heinrich events, which are indicative of the last Ice Age, but Dansgaard-Oeschger excursions, also indicative of significant climate events, were not present, a surprising find because both Heinrich events and Dansgaard-Oeschger excursions are featured prominently in stalagmite climate records from China, which is not far north of Borneo.

"To my knowledge, this is the first record that so clearly shows sensitivity to one set of major abrupt climate change events and not another," Cobb said. "These two types of abrupt change events appear to have different degrees of tropical Pacific involvement, and because the tropical Pacific speaks with such a loud voice when it does speak, we think this is extremely important for understanding the mechanisms underlying these events."

Stacy Carolin, a Georgia Tech Ph.D. candidate who gathered and analyzed the stalagmites, said the data adds significantly to the understanding of how various climate changes are felt in regions across the western tropical Pacific.

"You have to be impressed with the scope of what you are studying, and recognize that the state our climate is in today is incredibly different from Earth's climate during the last Ice Age," she said. "As we consider how humans may be affecting climate, dissecting what was going on tens of thousands of years ago in all regions of the globe can help scientists better predict how the Earth will respond to modern climate forcings."