Warming, cooling, and surface ice accumulation initiated by the release of water from the Athabasca Valles Flood Lava eruption on Mars

The Athabasca Valles Flood Lava (AVFL) eruption may have significantly influenced the Late Amazonian environment of Mars by emplacing hot lava and injecting large volumes of water into the atmosphere. Using the Laboratoire de Météorologie Dynamique Generic Planetary Climate Model, we simulate the dispersal of this water and its climatic effects. Within a day, vapor condenses into cloud layers and precipitates as ice, forming deposits up to ∼5 m thick around the vent. Clouds exert both warming and cooling influences: latent heat release raises atmospheric temperatures above the vent by up to ∼80 K and enhances local surface warming by ∼10 K, while cloud cover blocks radiation, cooling the lower troposphere by up to 30 K. Surface cooling is pronounced, with temperatures decreasing by ∼70 K due to persistent clouds and high-albedo ice. These processes suggest the AVFL eruption initiated a transient hydrological cycle and ice accumulation in tropical latitudes otherwise unfavorable for long-term stability. Our findings allow us to make predictions about the climate and environmental effects of future eruptions from Cerberus Fossae, a region that may still be volcanically active.