Arctic sovereignty under discussion

Top envoys from five nations gathered in Greenland on Tuesday to debate the right to exploit Arctic energy resources. Scientists say up to a quarter of the world's untapped oil and gas stocks could lie under the region's sea bed.

The controversy over energy rights to the Arctic intensified last year when a Russian research vessel planted a flag at the North Pole. Taking part in the conference are the US, Russia, Canada, Norway and Denmark, the five nations whose land borders the Arctic Ocean.

The Ocean is currently governed by the Law of the Sea Treaty, but the US is the only nation in the five that's not currently party to the treaty.