Melting ice in West Antarctica is a major concern for global sea levels, and a key area may already be unstable enough to unleash 3 meters of ocean rise, scientists said.

The study follows research published last year, led by NASA glaciologist Eric Rignot.

This warned that ice in Antarctica had entered a state of irreversible retreat, that the melting was considered unstoppable and could raise sea level by 1.2 meters.