Humans influencing climate since over 2000 yearsNew 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.