Could Mars Have Melted Ice Recently?

The study investigates whether liquid water could have formed Mars’ young gullies in the past 4 million years. Using advanced climate models, the authors find that surface frost cannot melt because sublimation cools it too strongly, and subsurface ice stays too deep and cold for melting. Even when ice is suddenly exposed, melting requires unrealistic conditions and produces too little water. The results suggest that most gullies likely formed through dry CO₂-driven processes rather than flowing water.