Polar Ice Is Live-Blogging Human History
Scientists reading layers of pollution can now tell what year Romans minted a lot of silver coins, what year a plague struck, and what year the Montreal Protocol cut CFCs.
Reliable witness.
Photographer: Mario Tama/Getty Images
By the dawn of the 20th century, when the first humans set foot on Antarctica’s seemingly pristine ice cap, pollution had beaten them there. Lead and other heavy metals quickly amassed in the ice in 1888 and beyond, leaving a record of the industrial revolution. Not a subtle one, either. It was like “a switch turning on,” said Joseph McConnell, a hydrologist and ice core expert with the Desert Research Institute in Nevada.
On both Greenland’s and Antarctica’s ice caps, snow settles in layers, like sediments, recording what was in the atmosphere, year by year. By digging out ice cores hundreds of feet long, scientists can read an environmental history going back thousands of years. Now, with newly precise measurements, McConnell and colleagues announced they can use Greenland’s ice to read subtle ups and down of lead pollution emanating from the Roman Empire.