Mars Without the Southern Perennial CO₂ Cover

The Martian South Polar Layered Deposits (SPLD) are composed mostly of ice and dust with a thin perennial (Formula presented.) cover and some internal (Formula presented.) ice layers. In the North, the seasonal (Formula presented.) cap is lost during summer, allowing (Formula presented.) O ice to sublimate into the atmosphere. In the South, the perennial (Formula presented.) cover prevents (Formula presented.) O ice sublimation. This work uses the Mars Planetary Climate Model to investigate how the (Formula presented.) O and (Formula presented.) cycles are affected if the thin perennial (Formula presented.) SPLD cover is lost. We find that during southern summer, the atmospheric water content will more than double in the south polar region. However, on a global scale, the NPLD is still the dominant source of humidity because of its larger surface area. When exposing some of the South Polar Cap buried water ice, the south polar cap becomes the dominant source of atmospheric humidity due to Mars's spin-orbital alignment.