Ice cores show OSU researchers the planet’s atmosphere in the past, predicts the future
A 60,000-year-old piece of ice melts away. Air that has been trapped and frozen in time within hundreds of microscopic bubbles tell the story of our planet.
The story of ice is the story of Earth’s air.
Ice coring research involves drilling a long cylinder of ice collected from the highest elevations in Greenland or the mountains of Antarctica. Due to the cold temperatures in these regions, the Ice Core Lab at Oregon State University drills old ice, frozen in time.
Chronological information is purely archived within the ice cores and dates back nearly 1 million years.
Researchers are able to learn when volcanic eruptions took place, study the sea salt spray and geologic dusts with what gases are trapped within ice cores.
Ice cores indicate what the earth’s atmosphere was like and what is next for the planet’s atmosphere.
Deep ice coring research began in Greenland during the early 1960s.
And at almost the same time, ice core drilling began in Antarctica.
Ice drilling efforts were spurred by the International Geophysical Year, an international endeavor to study the earth. Scientists involved with this research range from chemists to geologists to physicists.
For the ice to reach OSU’s lab, it is shipped by plane, boat and truck. Cold packs are placed into the box with the ice core to ensure it doesn’t melt.
Once the ice cores makes their way into the lab, Ice Core Lab director Ed Brook and his team use different analytical tools to measure gases.
Mass spectrometers are used to measure how much CO2, methane and nitrous oxide are present within the ice.
In the days before ice coring research, in order for scientists to learn what climate was like in the past, they had to look at critters that lived at the oceans’ surface. From there, they try to infer what the climate was like based on which type of organisms were living in certain places at certain times.
These research methods are known as proxies, which provide measurements of climate through an indirect approach.
“(Scientists) have to interpret what these proxies are telling us,” Brook said. “But the air within the bubbles of the ice is just the air. Very little proxy interpretation is needed. We can directly measure what the CO2 was 100,000 years ago.”
Ice cores may be the only data method like this available when learning about the past, Brook said.
Brook has been working with ice cores for 20 years, and throughout this time he has learned to translate the language of the ice.
Brook does this by studying air bubbles embedded within the cores.
Polar ice, the kind of ice researchers study in the lab, is formed from snowfall that is slowly compressed into solid sheets of ice.
In between each grain of snow, tightly compacted spaces of air get sealed off from the outside world. Ultimately, the polar ice intricately wields itself together by melting and then freezing.
Interestingly, the bubbles are uniform in their appearance, unlike the random bubbles in man-made ice cubes.
The oldest ice core sample that is continuous from top to bottom with no breaks in time is 800,000 years old.
“The oldest ice I have analyzed is 1 million years old,” Brook said. “It was pretty cool.”
Additionally, ice cores provide scientists with quantifiable data, which reveals a hotbed of climate change research.
Humans have radically changed the atmosphere since the Industrial Revolution — greenhouse gases have risen quite dramatically.
This is partly due to what researchers see in the ice throughout a large period of time. They have established a direct correlation between rising temperatures and greenhouse gas levels.
Other things affect temperature, too, but today’s atmosphere is remarkably unusual with respect to the natural past, which ice core researchers have observed.
How fast CO2 is arriving now is unsettling, Brook said.
The height of CO2 levels before the Industrial Revolution was 280 parts per million. We have now arrived at 400 parts per million.
“We’re kind of on a schedule to get up to something like 800 parts per million by the end of this century — and to me, that’s what’s scary,” Brook said.
As ice core researchers continue learning about the framework of global climate change, it’s clear that humans are facing unknown air quality.
“We have never seen in the natural part of the ice core record — before humans — anything like what the atmosphere is like now,” Brook said. “(Humans) have changed the atmosphere, and we should expect climate to change because of that.”