In the search for the factors that influence the Earth's climate, scientists are looking for something very particular: an ancient piece of ice that formed when ice ages were more frequent, approximately one million years ago. A piece of ice that fits this requirement could help researchers better understand the warming of the planet that is taking place right now.
Finding such a piece of ice might seem simple enough, but there are a few other criteria that this ancient piece of ice must meet, one being an ice core that allows scientists to observe changes in the atmosphere over time. Cores typically measure four to five inches in diameter and stretch for nearly two miles at a time. As of now, the oldest ones retrieved are around 800,000 years old.
"We really want ice that is 1.5 million years old," said Ed Brook, a professor of earth, ocean and atmospheric sciences at Oregon State University in Corvallis. "One million won't be quite good enough for our goal."
One of the biggest pieces of evidence for the warming of the planet is the increased interval between ice ages. Prior to one million years ago, these cycles took place approximately every 400,000 years, but since then they have increased to around 100,000 years.
Scientists believe that examination of the ice that formed prior to warming - when ice ages were more frequent - could yield information about climate warming and help us better understand how it affects us today.
"Why the cycles switched is a fundamental question," Brook said.
Researchers hope to examine carbon dioxide levels in the older ice and pinpoint how they changed over time. Generally, more carbon dioxide in the atmosphere equates to a warmer planet and less a cooler one.
As of last month, the Mauna Loa Research station in Hawaii measured 404 parts per million (ppm) of carbon dioxide in the atmosphere, an increase from the 3.76 measured a year prior.
"We have never seen anything above 300 parts per million in the last 800,000 years," Brook said. "We have never seen any levels remotely like the modern atmosphere."
Once the team begins their mission to find the ancient ice, it could take around four to five years to complete and will only be able to be conducted during the South Pole summer, which takes place from December to February.
"There's a lot of ice to get through," Brook said.
