We report that the concentration of CO2 over melting ice oscillates as long as water and ice coexist. A phenomenological model involving melting of CO2 containing ice leading to its release, readsorption of the vapor on ice, and dissolution in water is proposed. Thermokinetics of these processes lead to nonlinearity of the dynamics. This phenomenon is also observed over impure ice contaminated with salts or in the presence of nitrogen or air. Oscillations have been observed in several other solute or ice-water systems.