Disappearance of summer sea ice in Arctic a landmine, say scientists

The scientists who led the biggest-ever expedition to the Arctic have warned about the impacts of irreversible global warming. The scientists think the tipping point for irreversible global warming may have already been triggered. "The disappearance of summer sea ice in the Arctic is one of the first landmines in this minefield, one of the tipping points that we set off first when we push warming too far," said Markus Rex.