Ancient Rome was thirsty for resources. But while conquests had military and political motives, they were mostly driven by the search for metals. The metallurgical activities of the republic, and then of the empire, were so prolific that we still find their traces in the environment today — and not only in the form of perforated mountains and large mines such as those in Las Médulas, Spain. Rome’s environmental footprint can be found high up in the mountains, in the pollutants that metallurgy left trapped in the ice of the glaciers.
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Analysis in 2019 of the Col du Dôme glacier at the foot of the Mont Blanc in France revealed the presence of unusually high levels of lead and antimony for a period stretching roughly from 800 B.C. to A.D. 250. During those centuries, the amount of lead in the atmosphere increased tenfold. That significant increase is nevertheless unmatched by the hundredfold increase that occurred in more recent times due to the use of leaded fuels. But that is another story.
The study was carried out on three ice core samples taken from the glacier in 2016. Ice cores are cylinders drilled out of glaciers or polar ice sheets that let us to travel back in time; they allow us to study the composition of the atmosphere in past eras, through traces of pollutants, aerosols and other gases trapped in air bubbles. The deeper the ice is recovered, the farther back in time we travel, which makes cores one of the most reliable tools for reconstructing the climate of the past.
The problem is that most of the world’s permanent ice bodies are melting quickly, which is where our protagonists come in.
Ice memories
“Wherever we go, we see the same signs. The temperature is rising and glaciers are melting. It may not be very obvious in some cases, but most of them are disappearing. It’s very sad,” said Margit Schwikowski, a chemist and scientific head of the Ice Memory Foundation, a project to collect ice cores from the planet’s glaciers before they disappear, and preserve them in optimal conditions for future study.
“We don’t know, but it’s likely that for some glaciers it’s already too late,” Schwikowski said.
The project began in 2015 and a year later carried out its first drilling on the Col du Dôme glacier. There, it obtained the three ice cores that, among other things, have served to understand the levels of atmospheric pollution during Roman times.
It contains the climatic and atmospheric record for the entire Holocene
In 2017, the project collected two ice cores in Illimani, Bolivia, at more than 6,000 meters above sea level, which contain data that made it possible to reconstruct some environmental parameters from 18,000 years ago. After that, came drillings on Elbrus and Beluka in Russia, Grand Combin in Switzerland and Colle Gnifetti in Italy.
“Ice cores from glaciers do not usually allow us to travel in time beyond 200 years, but there are exceptions. That was the case with Colle Gnifetti, which is at an altitude of 4,600 meters on Monte Rosa in Italy. With its ice, we can go back 10,000 years: meaning it contains the climatic and atmospheric record for the entire Holocene, which is the Earth’s last interglacial period, and the one we are in today,” Schwikowski said.
A race against time
After Italy, the project went to Norway’s Svalbard islands (2023) and Italy’s Colle del Lys (2023). It’s next destination is Canada.
Ice core drilling is neither simple nor cheap, so the Ice Memory Foundation is always looking to partner with other scientific teams engaged in similar missions. A next project, which has yet to be confirmed, it may work with the University of Maine to extract ice core samples from the Eclipse Icefield in Yukon, Canada.
“We expect this core to contain 10,000 years of Pacific climate history. There are very few places on the planet where we can reconstruct the past of an ocean, which has a major influence on global climate,” explains Schwikowski.
Schwikowski says this ice core could “contain 10,000 years of Pacific climate history. There are very few places on the planet where we could reconstruct the past of an ocean that greatly influences the global climate.”
There, too, the project will be a race against time; studies on nearby glaciers, such as those in Juneau, show that melting has accelerated in recent decades. The Juneau Icefield, composed of more than 100 glaciers, is currently losing 200,000 liters per second.
An ice sanctuary
The Ice Memory Foundation aims to collect ice cores from 20 glaciers before 2035. In addition to those in Canada, it has its sights set on the Andean plateau in Peru, the Heard islands in Australia and various points in the peaks of Tajikistan, Pakistan and China (the Tibetan plateau and the Himalayas are known as the Earth’s third pole, with more than 46,000 glaciers).
In all of these places, the aim is always the same: to safeguard glacial ice records for future research, when most of the world’s glaciers will have disappeared — if we do not act.
“Glaciers are fantastic natural archives. In some, like the polar ones, we can even analyze the presence of greenhouse gases in the atmosphere from the past. But generally, they help us understand the climate, pollution and environmental conditions of other periods,” Schwikowski said.
We want more information about the past to allow us to understand what will happen in the future.
“For example, we are currently working on a paper on the reconstruction of heavy metal pollution in the countries of the former Soviet Union, as there are no reliable records. We can also observe in the increase of sulfur dioxide in the atmosphere since we started burning fossil fuels and its subsequent decrease in some areas where pollution control measures were taken.”
“In the end, it’s is all about data. We want more information about the past to allow us to understand what will happen in the future,” she said.
To do this, the ice cores from the project must be kept in a safe place. And there is no better place than Antarctica. The last step of the Ice Memory Foundation will be to store the cores in a kind of international ice sanctuary, built next to the Concordia scientific base, the only one on the Antarctic plateau. There, with natural conditions of minus 50 °C, the ice core samples will be able to survive a few more centuries — at least, that’s what the researchers hope.
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