Posted: Jan 22, 2021 Deep sea fossilized skeletons from 45 million years ago. Credit: Stanley A. Kling, Scripps IO. Predictions of future climate change require a clear and nuanced understanding of Earth’s past climate. University of Hawai‘i at Mānoa oceanographers solved a controversy that has been debated in scientific literature for decades by fully reconciling climate and carbon cycle trends of the past 50 million years. Their research was published in Throughout Earth’s history, global climate and the global carbon cycle have undergone significant changes, some of which challenge the current understanding of carbon cycle dynamics. Less carbon dioxide in the atmosphere cools Earth and decreases weathering of rocks and minerals on land over long time scales. Less weathering should lead to a shallower calcite compensation depth (CCD), which is the depth in the ocean where the rate of carbonate material raining down equals the rate of carbo