A study of stalagmites showed the Western Tropical Pacific was affected differently by climate change than the rest of the world, according to Georgia Tech.
By studying stalagmites in tropical Borneo, researchers at the University were able to see back 100,000 years and create a climate record. The findings may be able to allow scientists to see into the future as well, and predict how the Earth may respond to climate change.
The researchers performed an oxygen isotope analysis of four ancient stalagmite in different caves around the region.
They discovered 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 the university.
In modern times, even the smallest changes in tropical Pacific atmosphere can affect the entire global climate.
There have not been any recorded climate events that have the "length, resolution and age controls" to measure how the region would actually respond to a drastic change.
This is a new record from a very important area of the world," said Kim Cobb, an associate professor at the School of Earth and Atmospheric Sciences. "This record will provide a new piece of the puzzle from the tropical Pacific showing us how that climate system has responded to forcing events over the past 100,000 years."
It was interesting which types of climate events the researchers were able to get from the stalagmites. The samples showed evidence of a major climate change called Heinrich events. However there was no indication of another prominent event known as a Dansgaard-Oeschger excursion, this is strange because stalagmites in China provided proof of both events and the area's are not far from each other.
"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."
The researchers also found a change in the stalagmites right around the time that super-volcano Toba erupted, about 74,000 years in the past.
In order to perform the study, the team measured the ratio of oxygen isotopes in the calcium carbonate that makes up the stalagmites. This can give insight into the ratio of oxygen isotopes in the rainfall that formed the stalagmites, which formed at a rate of about one centimeter every 1,000 years.
Stacy Carolin, a Georgia Tech Ph.D. candidate who worked on the project cut open the ancient stalagmites and took samples of each centimeter, she then measured the uranium and thorium isotope ratios of each piece. Measuring these levels can map out a history of the precipitation levels in the region during each specific time frame.
"Stalagmites are time capsules of climate signals from thousands of years in the past," Carolin said. "We have instrumental records of climate only for the past 100 years or so, and if we want to look deeper into the past, we have to find records like these that locked in climate signals we can extract today."