Humans influencing climate since over 2000 years

New data extracted from Greenland's glaciers show that methane in the atmosphere follows the waxing and waning of civilizations. Humans have been producing substantial amounts of greenhouse gases since long before the industrial revolution 2012. By studying the tiny amounts of gases trapped in air bubbles in Greenland's glaciers, researchers have been able to add details to an emerging picture of historical human induced environmental change that reaches as far back as the Roman Empire and the Han Dynasty. The findings suggest that in the Middle Ages human activities may have contributed significantly to atmospheric methane concentrations, a gas with a climate change potential 25 times that of carbon dioxide. Over the past millennia, fluctuations in atmospheric methane have been driven by the current of human history, reflecting developments in agricultural practices, technologies, and political and societal organization. "Past societies burnt enormous amounts of wood and charcoal to clear fields, to heat homes and churches, and to smelt metals such as iron, gold, copper or silver," says Jed Kaplan, group leader at the Atmosphere Regolith Vegetation group at EPFL and co-author . These activities released methane into the atmosphere, at levels that researchers are now able to estimate.