An ambitious effort to understand the Earth’s climate over the past 485 million years has revealed a history of wild shifts and far hotter temperatures than scientists previously realized — offering a reminder of how much change the planet has already endured and a warning about the unprecedented rate of warming caused by humans. The timeline, published Thursday in the journal Science, is the most rigorous reconstruction of Earth’s past temperatures ever produced, the authors say. Created by combining more than 150,000 pieces of fossil evidence with state-of-the-art climate models, it shows the intimate link between carbon dioxide and global...