A new study suggests that a million years ago, glaciers began sticking more persistently to their beds, triggering cycles of longer ice ages. Here, ice discharged from Iceland’s Breiðamerkurjökull glacier on its way to the Atlantic ocean. Credit: Kevin Krajick/Earth Institute Why did glacial cycles intensify a million years ago? Researchers find clues on the bed of the Atlantic Ocean. Something big happened to the planet about a million years ago. There was a major shift in the response of Earth’s climate system to variations in our orbit around the Sun. The shift is called the Mid-Pleistocene Transition. Before the...