The history of ancient Rome is embedded in Arctic ice
Lead pollution found in Arctic ice explains significant economic events in ancient European civilizations
Climate scientists often point to melting ice sheets in our planet's coldest regions as signs of damage to the environment.
In the grip of the ice cores of Greenland, climate and environmental scientist Joe McConnell found evidence of lead pollution dating back to the Greek and Roman empires.
McConnell, an ice core scientist at Desert Research Institute, studied samples of ice formed around 1000 BC to about AD 800. The research team also included historians and archaeologists from Oxford University.
"What we're seeing is sort of the big picture emissions from from Rome at that time," McConnell tells Day 6 host Brent Bambury.
Although Greenland's ice sheet was far away from Roman mines and foundries, the ice kept proof of even the small quantities of particles that reached that distance.
The details coming out of the ice inform scientists not only about historic pollution, but also its sources — and ultimately, the rise and fall of the Roman economy.
"You are able to extract so much detail ... [about] historical events, that makes this story so remarkable," McConnell says.
He adds a lot this work relies on accurate dating of the ice.
"It's very much like tree ring record. You start at a known date," he says.
McConnell's team started at a known volcanic eruption in the region around AD 1258-58 and started counting backwards.
"It's that dating that allows us to connect to this lead pollution record so precisely to historical events."
The idea that that human emissions can affect such remote parts of the environment is pretty amazing.- Joe McConnell
For example, the rise of pollution in early 900 BC was connected to the Phoenicians expanding into the western Mediterranean, according to McConnell.
Lead continued to rise and fall with the start and end of wars and other known historical events until about 100 BC when pollution peaked.
That indicated "a vigorous economy," according to McConnell.
"And then the last 80 years of the Roman Republic were a disaster," he says. "I mean things plummeted by a factor of four."
Something similar in Antarctica
Greenland's ice is not unique in its ability to store information about historic industrial moves that happened far from where it stood.
There are clear signs that industrial pollution from Australia reached the South Pole 22 years before famous explorers Roald Amundsen and Robert Falcon Scott arrived, McConnell says.
"So they were clearly skiing or travelling over polluted snow."
The historical archive of pollution helps inform McConnell's more contemporary work on around climate change.
"The idea that that human emissions can affect such remote parts of the environment is pretty amazing."
To hear our full interview with Joe McConnell, download our podcast or click 'Listen' above.
CORRECTION: Roald Amundsen's name was misspelled in a previous version of this story. It has been corrected.