A research team used 13 ice-cores from Greenland and the Russian Arctic to analyze the economic development in this area over the past 1,500 years. The European history, since the Middle Ages and until our day, has left traces in unexpected places.
The researchers found that lead concentrations in the ice-cores highlight wars, plagues, and famines. Commercial and industrial processes have emitted lead into the atmosphere for thousands of years, from currency minting in ancient Rome to the burning of fossil fuels today. This lead pollution travels on wind currents through the atmosphere, eventually settling on places like the ice sheet in Greenland and other parts of the Arctic.
According to the German news agency, an international research team led by Joseph McConnell from the Desert Research Institute in Reno used 13 Arctic ice-cores to measure, date and analyze lead emissions.
In their study published in the journal Proceedings of the National Academy of Sciences, the researchers focused their efforts to examine years between 500 and 2010 CE, a period of time that extended from the Middle Ages through the Modern Period to the present.
This study co-authored by researchers from the Alfred Wegener Institute for Polar and Marine Research in Germany, is another episode in a series of studies conducted by McConnell, who analyzed arctic ice-cores dating back to the period between 1100 BCE and 800 CE.
In a statement issued by the institute, McConnell explained: "Our study involving 13 ice-cores instead of just one, shows that prior to the Industrial Revolution, lead pollution was pervasive and surprisingly similar across the Arctic and undoubtedly the result of European emissions."
"The ice-core array provides, with amazing detail, a continuous record of European and later North American, industrial emissions during the past 1,500 years," he continued.
The research team found that increases in lead concentration in the ice-cores track closely with periods of expansion in Europe, the advent of new technologies, and economic prosperity.
"Sustained increases in lead pollution during the Early and High Middle Ages (about 800 to 1300 CE), indicate widespread economic growth, particularly in central Europe as new mining areas were discovered in places like the German mountains," added McConnell.
Despite these fluctuations, the Arctic lead pollution doubled many times in the past 1,500 years, by 250-300 folds, from the Middle Ages to the 1980's.
And although the lead pollution in Arctic ice declined 80% later, since the passage of pollution abatement policies, including the 1970 Clean Air Act in the United States, still, lead levels are about 60 times higher today than they were at the beginning of the Middle Ages.
