A new study shows past climate changes in the Arctic are linked to those in Antarctica.
A research team compared ice cores from the northern and southern hemispheres, and found abrupt temperature changes in the North Pole had an influence on South Pole temperatures, Montana State University reported. Climate change that originated in the Arctic appeared to spread to the Antarctic.
"The topic is very important to understanding how climate oscillates between the north and south poles," said polar ecologist John Priscu."Such information provides us with a new perspective on global climate dynamics and will help us assess future climate regimes."
The team chose to take ice core samples from an area in West Antarctica called the WAIS Divide because of its thick ice, simple ice flow, and annual snow fall.
"When snow falls at WAIS Divide, it rarely melts, and instead builds up in thick annual layers, which are compressed into ice by subsequent snowfall," the team said. "The compacted snow contains dust, microbes, chemicals and atmospheric gases, which are trapped in the ice. The dust, bacteria and other chemicals in the ice are indicators of past climate, and the gas contained in air bubbles is a sample of the ancient atmosphere. The deeper the ice, the older it is, and the further back in time measurements can be made."
The team took an ice core sample from the site that was 4.8 inches in diameter and 11,200 feet long. Comparisons with ice cores from the northern hemisphere suggest the climate in Greenland was unstable during the last ice age and experienced dramatic temperatures changes. The phenomenon, dubbed the Dansgaard-Oeschger events, went on for a few thousand years, but started and ended in only a matter of decades.
Temperature changes in Antarctica followed an opposite pattern in which temperatures were cooling as Greenland heated up. These abrupt climate changes are believed to have originated around Greenland. These past temperature changes were different than what we see today. They were regional and triggered by the collapse of ice sheets, today's changes are linked to increasing levels of atmospheric carbon dioxide.
"Nevertheless, understanding how and why climate changed in the past is important because it helps scientists predict how Earth's climate will respond to human-caused increases in greenhouse gases," the team concluded.
The findings were published in a recent edition of the journal Nature.
