Two peer-reviewed studies have sharpened scientists’ understanding of why Mars never sustained long-term life despite evidence of ancient rivers and lakes. In a paper published in Nature, a team led by University of Chicago planetary scientist Edwin Kite used data from NASA’s Curiosity rover to model how carbonate-rich rocks on the red planet soaked up atmospheric carbon dioxide. The process, coupled with Mars’ weak volcanic outgassing, would have curtailed greenhouse warming, allowing only short, sporadic episodes of liquid water followed by roughly 100 million-year stretches of deep-freeze desert conditions. Complementing those findings, a separate report in Nature Astronomy analysed 150 clay deposits mapped by NASA’s Mars Reconnaissance Orbiter. Rhianna Moore of the University of Texas and colleagues conclude that the thick, mineral-rich layers formed in stable, low-lying basins fed by standing water about 3.7 billion years ago, creating pockets that could have supported life for extended periods. Together, the studies suggest Mars offered fleeting ‘oases’ of habitability rather than a planet-wide, enduring environment, underscoring the scientific value of returning rock samples that the United States and China aim to collect later this decade.