Volcanic winter is a hypothetical environment effect of a sharp volcano outbreaks. Volcanic winter of an extremely large and explosive volcanic eruptions. Temperature reduction caused by volcanic ash and sulfuric acid obscuring the sun and reducing temperatures and raises the planets even reflectivity of solar radiation. The effect of volcanic winter is the first warmer temperatures, and then follow the colder temperatures that could lead to new ice age and the extinction of both plant and animal species.

Dr. Lisa Park thought that the planet Novus had suffered a nuclear winter after hearing that the two nations on Novus had nuclear weapons and were in the Cold War with each other. Lt. Matthew Scott's analysis showed the temperature of the surface was colder but also found high levels of ash and sulfur as Dr. Nicholas Rush confirmed that there was a volcanic winter that was caused by a supervolcano. (SGU: "Epilogue")

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