A new study explores a possible connection between changes in the Arctic's climate to those that occurred in the Antarctic in the past.
Experts from the West Antarctic Ice Sheet (WAIS) Divide Project studied evidence on an ice core recovered from West Antarctica that showed a consistent link between sudden changes in temperatures on Antarctica and Greenland during the previous ice age. The researchers believe that this evidence presents a better image of how climates in the northern and southern hemispheres of the world are connected.
Professor John Priscu, a polar ecologist from Montana State University (MSU), said that it is important to understand how the climate moves back and forth between the north and south poles as it can help create new strategies on how to deal with future climate regimes.
According to their study, the climate on Greenland during the previous ice age was highly unstable, with drastic shifts in mean annual temperature occurring within a span of several decades. These significant events, called "Dansgaard-Oeschger," were believed to have taken place every few thousand years in the last ice age.
Shifts in Antarctica's temperature displayed a different pattern, wherein Antarctica was cooling just when Greenland was starting to become warm, and vice versa.
The researchers found out that the sudden changes in the climate on Greenland happened first, with the climate change on Antarctica occurring only after about 200 years.
The study, funded by the National Science Foundation, featured 18 drastic climate changes that took place during the past 68,000 years.
Lead author Christo Buizert from Oregon State University pointed out that the temperature changes between the north and south poles suggest that heat redistribution also occurs between the opposite hemispheres. While there is still no definite explanation as to what causes the abrupt shifts, Buizert said that understanding their timing could provide valuable insight on its mechanisms.
"The 200-year lag that we observe certainly hints at an oceanic mechanism," Buizert explained.
"If the climatic changes were propagated by the atmosphere, the Antarctic response would have occurred in a matter of years or decades, not two centuries. The ocean is large and sluggish, thus the 200-year time lag is a pretty clear fingerprint of the ocean's involvement."
The researchers noted that the climate changes during the last ice age differ significantly from what is seen today. The climate events recorded from the ice age were more regional and was influenced by major shifts in ocean circulation. The warming that is experienced today happens on a global scope and is primarily caused by emissions of carbon dioxide that accumulate in the atmosphere.
The WAIS Divide Project study is published in the recent edition of the journal Nature.
Photo: U.S. Geological Survey | Flickr
