Ultimately, the Scandinavian occupation of Iceland could have been transformative enough to mitigate forest fires on the island.
A research team analyzing an ice core quarried from the area has discovered that the chemical signatures of the wildfires soaked at the time, northern communities settled on the landmass, which to this day is oddly treeless. In July, they published their findings in the journal Climate of yesteryear.
“You can still see what the primeval forest looked like in places like Fnjóskadalur or Ásbyrgi,” says Kathryn Catlin, an anthropologist geoarchaeologist at Jacksonville State University who was not involved in the study. But this summer’s report on ice core recordings could add further evidence to something researchers like Catlin have long known: “The Nordic people have radically changed the landscape,” she notes.
Learning how the Scandinavians altered their environment, according to the study’s authors, provides a useful context for understanding the type of environmental impacts that tree eradication activities could cause today.
Get to the heart of it
“The state of ice cores is closely linked to human history,” says Delia Segato, paleoclimatologist at Ca ‘Foscari University in Venice and co-author of the recent study Climate of yesteryear to study. Extracting segments of soil (or ice) that penetrate the ground can reveal layers of history – chemicals in the atmosphere can settle on the earth and slowly build up in a chronological record. Roman economic activity, for example, was approximated by extracts of ice cores. Civilization has brewed lead in the atmosphere while striking coins and particles deposited in Greenland ice in stacked levels, mimicking the financial fluctuations of the empire.
By inspecting cylinders of material extracted from deep underground, researchers already knew that the Scandinavians had cleared many trees. Although Icelandic sagas refer to an ancient forest-covered landscape, scientists have looked for concrete evidence of these long-extinct trees by pulling vertical cores of sediment from peat bogs and lake beds, Catlin explains. Specifically, examining tree pollen samples illustrates an unusual historical change. “What this shows, across Iceland is a dramatic drop in tree pollen and a corresponding increase in grasses and sedges around 1,100 years ago when the Scandinavians first came to the island,” Catlin explains.
So when Segato and his colleagues had access to an ice core that a international group of researchers Taken from an ice cap in eastern Greenland, they decided to see what other signals of northern activity were lurking in the frozen water.
The team specifically looked for compounds that are released into the air during a forest fire as carbon black, a by-product of burn fossil fuels and plant life, and levoglucosan, which appears when plant cell walls become inflamed. The fire’s fingerprints are suspended in the air, which is why the researchers were able to look for signs of Icelandic burns in the ice coming from Greenland: the team concluded.
Melting of the part of the ice core corresponding to the Scandinavian occupation and measurement of the levels of the selected fire markers showed that the prevalence of forest fires declined somewhat when the Scandinavians arrived.
To make sure that the drop in fire markers was not due to a larger phenomenon such as significant climate change, the team also looked at the levels of the same compounds found in other cores. These included an extract of ice from northern Greenland which retains fire residue soufflé from North America, explains Andrea Spolaor, paleoclimatologist at Ca ‘Foscari University in Venice and co-author of the article.
But the drop in chemical signatures in the Greenland ice core appeared to be distinct. “This means that the signal we are looking for is something new,” says Spolaor. If the reduction in forest fire residue in Iceland was not from global climatic fluctuations, it was likely a result of human activity, Spolaor says, that the Scandinavians cut so much flammable material that forest fires became less frequent.
It’s hard to say whether, compared to their time, the Scandinavians were unusually destructive in their new surroundings, Catlin says. Unlike most other parts of the world, indigenous communities had not inhabited the island before the arrival of the Scandinavians. The sudden arrival of man makes it easier to determine how the presence of a somewhat industrialized medieval society could distort a landscape. “There is no easy comparison between the impact of Nordic agriculture in Iceland and the impact of similar technologies in Scandinavia or the rest of medieval Europe,” says Catlin, “because these environments had already adapted to human impacts over several millennia.
Likewise, it is difficult to assess whether the consequences of deforestation 1,000 years ago will be repeated in our present day of massive logging. Although some parts of the world continue to cut down forests to further develop the land, trees are steadily blazing as global warming progresses, Spolaor says.
And while past events in Iceland are not an exact predictor of what will happen as climate change and land use planning progresses, these major changes still provide useful insight for today. “The climate of the past in general fits perfectly with what is happening now,” says Segato, “because otherwise we wouldn’t understand how dramatic these changes are. “