Dramatic shift in ice age rhythm pinned to carbon dioxide

Related Research Article Global and regional temperature change over the past 4.5 million years BY Peter U. Clark et al. Science 22 Feb 2024 Roughly 1.5 million years ago, Earth went through a radical climatic shift. The planet had already been slipping in and out of ice ages every 40,000 years, provoked by wobbles in its orbit. But then, something flipped. The ice ages began to grow stronger and longer, with durations of 100,000 years, and overall, the planet grew cooler. And nothing about Earth’s orbit could explain it. The cause of this Mid-Pleistocene Transition (MPT), as it’s known, has been a major mystery for decades. A new compilation of global temperatures covering the past 4.5 million years, published this week in Science , points a finger at a familiar molecule : carbon dioxide. It suggests that a strengthening of an ocean pump in the waters around Antarctica sucked carbon dioxide out of the air and sent it plunging to the abyss, cooling the planet and intensifying the ice ages. The study even suggests the climate, then and now, could be more sensitive to carbon dioxide than modelers expect. “The power of the [carbon dioxide] control knob on the climate system really comes out of this work,” says Ruth Mottram, a ...
Source: ScienceNOW - Category: Science Source Type: news