Climate change melts Marion Island's snow and ice

Abstract

Since the mid-1960s, ice on the peaks of Marion Island has undergone conspicuous melting. Climatic amelioration and declining precipitation over the past four decades are responsible for the disappearance of a snowline and the 'Ice Plateau', which evidently had the characteristics of a small glacier. Ice remnants are now scoria-covered, occupying slopes and valley floors beneath the high peaks. Melting ice gives rise to hummocky, thermokarst terrain and meltwater channels. Owing to an increase in the active-layer thickness and degradation of permafrost, the slopes now exhibit erosional landforms and debris flows in summer. Continued climatic warming is expected to destabilize scoria cone slopes and increase the incidence of mass movements as slopes adjust to reduced cohesion. Increased geomorphic activity and material mobility will initially inhibit plant colonization on the newly sub-aerially exposed surfaces.