the.com/volcanic winter

means A period of abnormal global cooling caused by volcanic ash and sulfate aerosols blocking sunlight after a massive eruption.

from A 20th-century scientific compound, modeled on the older phrase 'nuclear winter.' 'Volcanic' traces back to Vulcan, the Roman god of fire and the forge, whose name was lent to fire-mountains themselves; 'winter' is an ancient Germanic word for the cold season. Scientists stitched the two together once they understood that eruptions like Tambora in 1815 could throw enough sulfur dioxide into the stratosphere to dim the sun and chill the planet for years — the 1816 'Year Without a Summer' being the famous case study that gave the concept its teeth.