Rise and fall of Roman Empire exposed in Greenland ice samples

first_img Rise and fall of Roman Empire exposed in Greenland ice samples LouieLea/shutterstock.com Email Lead pollution from the Roman Empire fell on Greenland—where it was preserved in layers of ice. Modern people aren’t the only ones who’ve polluted the atmosphere. Two thousand years ago, the Romans smelted precious ores in clay furnaces, extracting silver and belching lead into the sky. Some of that lead settled on Greenland’s ice cap and mixed in with ever-accumulating layers of ice. Now, scientists studying annual deposits of those ice layers have found that spikes and dips in lead pollution during the Roman era mirror the timing of many historical events, including wars fought by Julius Caesar.The level of detail is “astounding,” says Dennis Kehoe, a scholar of Roman economic history and law at Tulane University in New Orleans, Louisiana, who wasn’t involved in the work. What really impressed him was how closely the lead pollution numbers tracked what ancient historians know about the expansion and collapse of the Roman economy—a system built on silver coinage known as denarius. “It’s really the rise and fall of a monetary system based on silver,” he says. “Prices were reckoned in silver, so they had to have silver.”Scientists have known about the Roman-era spike in lead pollution since the 1990s. Back then, researchers measured lead levels at a few places along the length of cores extracted from Greenland’s ice cap—with each measurement representing a 2-year period. Later studies confirmed the same pattern in soil samples from peat bogs in Spain, Scotland, and the Faroe Islands. But those studies couldn’t show how lead pollution changed year by year. Sign up for our daily newsletter Get more great content like this delivered right to you! Countrycenter_img Country * Afghanistan Aland Islands Albania Algeria Andorra Angola Anguilla Antarctica Antigua and Barbuda Argentina Armenia Aruba Australia Austria Azerbaijan Bahamas Bahrain Bangladesh Barbados Belarus Belgium Belize Benin Bermuda Bhutan Bolivia, Plurinational State of Bonaire, Sint Eustatius and Saba Bosnia and Herzegovina Botswana Bouvet Island Brazil British Indian Ocean Territory Brunei Darussalam Bulgaria Burkina Faso Burundi Cambodia Cameroon Canada Cape Verde Cayman Islands Central African Republic Chad Chile China Christmas Island Cocos (Keeling) Islands Colombia Comoros Congo Congo, the Democratic Republic of the Cook Islands Costa Rica Cote d’Ivoire Croatia Cuba Curaçao Cyprus Czech Republic Denmark Djibouti Dominica Dominican Republic Ecuador Egypt El Salvador Equatorial Guinea Eritrea Estonia Ethiopia Falkland Islands (Malvinas) Faroe Islands Fiji Finland France French Guiana French Polynesia French Southern Territories Gabon Gambia Georgia Germany Ghana Gibraltar Greece Greenland Grenada Guadeloupe Guatemala Guernsey Guinea Guinea-Bissau Guyana Haiti Heard Island and McDonald Islands Holy See (Vatican City State) Honduras Hungary Iceland India Indonesia Iran, Islamic Republic of Iraq Ireland Isle of Man Israel Italy Jamaica Japan Jersey Jordan Kazakhstan Kenya Kiribati Korea, Democratic People’s Republic of Korea, Republic of Kuwait Kyrgyzstan Lao People’s Democratic Republic Latvia Lebanon Lesotho Liberia Libyan Arab Jamahiriya Liechtenstein Lithuania Luxembourg Macao Macedonia, the former Yugoslav Republic of Madagascar Malawi Malaysia Maldives Mali Malta Martinique Mauritania Mauritius Mayotte Mexico Moldova, Republic of Monaco Mongolia Montenegro Montserrat Morocco Mozambique Myanmar Namibia Nauru Nepal Netherlands New Caledonia New Zealand Nicaragua Niger Nigeria Niue Norfolk Island Norway Oman Pakistan Palestine Panama Papua New Guinea Paraguay Peru Philippines Pitcairn Poland Portugal Qatar Reunion Romania Russian Federation Rwanda Saint Barthélemy Saint Helena, Ascension and Tristan da Cunha Saint Kitts and Nevis Saint Lucia Saint Martin (French part) Saint Pierre and Miquelon Saint Vincent and the Grenadines Samoa San Marino Sao Tome and Principe Saudi Arabia Senegal Serbia Seychelles Sierra Leone Singapore Sint Maarten (Dutch part) Slovakia Slovenia Solomon Islands Somalia South Africa South Georgia and the South Sandwich Islands South Sudan Spain Sri Lanka Sudan Suriname Svalbard and Jan Mayen Swaziland Sweden Switzerland Syrian Arab Republic Taiwan Tajikistan Tanzania, United Republic of Thailand Timor-Leste Togo Tokelau Tonga Trinidad and Tobago Tunisia Turkey Turkmenistan Turks and Caicos Islands Tuvalu Uganda Ukraine United Arab Emirates United Kingdom United States Uruguay Uzbekistan Vanuatu Venezuela, Bolivarian Republic of Vietnam Virgin Islands, British Wallis and Futuna Western Sahara Yemen Zambia Zimbabwe By Katie LanginMay. 14, 2018 , 3:00 PM Click to view the privacy policy. Required fields are indicated by an asterisk (*) So Andrew Wilson, an archaeologist at the University of Oxford in the United Kingdom and an expert on the Roman era, teamed up with ice core experts to get a more complete picture. The team measured lead levels along a roughly 400-meter cross-section of Greenland ice, representing layers that froze between 1100 B.C.E. and 800 C.E. They melted the ice bit by bit, from one end to the other, and siphoned off the ice melt for analysis—obtaining around 12 measurements per year during the Roman era. Not all the lead came from pollution related to ore smelting; some came from naturally occurring dust and volcanic emissions, which researchers estimated and subtracted from the total lead count.The result: an incredibly detailed 1900-year timeline of Roman lead pollution, published today in the Proceedings of the National Academy of Sciences. Lead pollution was greatest at the height of the Roman Empire—during the first century C.E.—at levels roughly six times higher than during the 11th century B.C.E. But after the Antonine Plague hit in 165 C.E., likely killing millions, lead pollution suddenly dropped back down to pre-Roman levels and remained that way for 500 years. Dips in lead pollution also occurred in the middle of the Roman era, particularly when wars erupted in Spain—a hot spot for lead-silver smelting—during the last few centuries B.C.E.Based on air circulation patterns, the team thinks that the Roman-era pollution, which peaked annually at just under a millionth of a gram of lead deposited per square meter, came mostly from the western half of the Roman empire, in western and northern Europe. By comparison, the amount of lead that fell on Greenland is roughly 50 times lower than levels in the 1900s, says Joe McConnell, an environmental scientist at the Desert Research Institute in Reno, Nevada, and lead author on the study.The work “raises all kinds of interesting questions,” says Kevin Butcher, an ancient historian at The University of Warwick in Coventry, U.K. He says there are a few puzzling points where there is a mismatch between peaks in lead pollution and silver coin production, making him wonder whether the Romans were smelting and stockpiling silver—but not turning it into coins right away. The data, he says, are “food for thought.”last_img

Have any Question or Comment?

Leave a Reply

Your email address will not be published. Required fields are marked *