As planetary ice recedes, it’s revealing secrets about human history. The latest example of that is in Norway, where a group of researchers has reconstructed 6,000 years of history based on more than 2,000 artifacts that have melted out of ice patches.
The new timeline, published this week in Royal Society Open Science, provides insights into how people responded to past climate shocks.
Ice patches are similar to glaciers in that they’re long-living hunks of ice replenished by snow each winter. But they differ in that they don’t move. That means that any artifacts left on them are simply entombed in the ice rather than ground to a fine dust, which is what happens to artifacts trapped in glaciers as they slide down the mountain.
Now that climate change is causing ice to melt, those artifacts are once again seeing the light of day after thousands of frozen years. In case of Oppland, Norway, some artifacts have been dated back to 6,000 years ago.
The wealth of artifacts recovered in Oppland (or any ice patch for that matter) are delicate and after centuries of life without air, they degrade and can be destroyed by the elements in a matter of days if nobody finds them. That makes the scientists’ work equal parts detective and EMT.
“We have a responsibility to rescue what is being exposed and thus destroyed,” James Barrett, an ice archeologist from the University of Cambridge who worked on the study, told Earther.
Saving the artifacts has allowed Barrett and his colleagues to reconstruct history. That’s yielded some pretty fascinating and at times counterintuitive theories on how people lived, and how climate and society are intimately tied together.
The earliest artifacts date to 6,000 years ago, which Barrett said are unique in their own right. But the artifact record that allows the scientists to spin their historical yarn begins to pick up steam in the third century.
That’s a period when agriculture and economic activity started to take hold in the valleys populated by Nordic people, according to a blog post by Lars Pilo, another study author who works with the Oppland County Council Department of Cultural Heritage. But hunting was still a large part of society, and with comparably mild weather and small glaciers and ice patches, it was relatively easy to hunt and travel over the mountains.
The weather took a turn for the worse during a period called the Late Antique Little Ice Age. From 536 AD until around 660 AD, a series of volcanic eruptions ushered in cold weather around the globe. The chill meant ice once again grew, making the mountains less hospitable.
Yet the researchers found that during that period, the number of artifacts continued to increase, perhaps because conditions at lower elevations were so dire.
“There are hints that use of the high mountains continued, perhaps to buffer losses from poor harvests in the valley farms,” Barrett said. “This last issue is one we need to explore further; it’s a direction for future research.”
The number of artifacts peaked in the Viking Age, which lasted from around the late eighth century until the early 10th century. During this period, exploration was the name of the game. Ships were setting out across the sea, contributing to a larger trading economy that was in part driven by natural resources brought down from the mountains.
“The high mountains were part of this story, and ice-patch finds may even have increased because of distant demand for products such as furs and antler,” Barrett said.
After that, artifacts drop off owing to new hunting methods that relied more on trapping herds of reindeer, and less on shooting arrows. The Black Plague also likely played a role as society became more closed.
There are almost certainly more pieces of history still lodged in the ice, including artifacts from a 1,600-year period starting in 3,800 BC that is still a complete blank spot in the archeologists’ logs. It could be that artifacts from that period are rare, or that they’ve melted out and been destroyed already.
Filling in this and other gaps provides a richer glimpse of the past, which is a major win archeologists, historians and really anyone who wants to understand how society evolved. But Barrett said the fact that we’re acquiring this new knowledge because of climate change is “important cautionary tale” for everyone living on Earth right now.