Observations of the Arctic reveal that the Arctic Ocean is covered by less ice each summer than the previous summer  If this warming trend continues, within 50 years the Arctic Ocean will be ice free during the summer months  This occurrence would in itself have little or no effect on global sea levels, since the melting of ice floating in water does not affect the water level
However, serious consequences to sea levels would eventually result, because
in the spring, melting sea ice would cause more icebergs to be created and to drift south into shipping routes