We model adsorption isotherms of water on the calcite (1014) surface using a polarizable water model in a variable particle number simulation. The sampling procedure employs a molecular dynamics-Monte Carlo hybrid technique, which consists of a classical molecular dynamics simulation combined with spatially random removal and insertion trials. The fluctuating charge algorithm is used to describe the many-body interaction of induced polarization during the simulations. We obtain the isotherms and isosteric heats of adsorption at 278 and 298 K. For the higher temperature we present a detailed analysis of the adsorbate structure for coverages ranging from the monolayer regime to the bulk interface.