evidence: One day in the next couple of years, everyone in the world will lose a second of their time. Exactly when that will happen is being influenced by humans, according to a new study, as melting polar ice alters the Earth’s rotation and changes time itself. [...] Changes in Earth’s rotation over the long term have been dominated by the friction of the tides on the ocean floor — which has slowed down its rotation. Recently, the impacts of melting polar ice, driven by humans burning planet-heating fossil fuels, have become a significant factor, Agnew said. As the ice melts into the ocean, meltwater moves from the poles toward the equator, which further slows the speed of the Earth’s rotation. [...] Polar ice melt "has been large enough to noticeably affect the rotation of the entire Earth in a way that is unprecedented," Agnew said. "To me, the fact that human beings have caused the rotation of the Earth to change is kind of amazing."