Researchers have developed a new isotopic method to analyze the recent history of large stratospheric volcanic eruptions, using 2,600 years’ worth of records contained in ice cores from Antarctica. Stratospheric eruptions can launch sulfate particles more than 6 miles above Earth’s surface, where they reflect sunlight and temporarily cool the planet. By understanding the history of big eruptions, researchers can place short cooling episodes and other climate events into the context of large-scale climate patterns.