Nordic nations sounded the alarm about a quickening melt of Arctic ice and said the thaw might soon prove irreversible because of global warming.

Sweden, Finland, Denmark, Norway and Iceland also urged all governments to agree before the end of 2009 a broader UN plan to curb greenhouse gases in succession to the Kyoto Protocol.

"The Arctic and the world cannot wait any longer," environment ministers from the five nations said in a joint statement after talks in Oslo. The five all have Arctic territories.

"The climate is hurtling towards a turning point after which irreversible processes will have been set in motion," they said of the Arctic thaw.

They noted the ice on the Arctic Ocean shrank in September to 4.13 million sq km, the smallest since satellite records began in 1979 and far eclipsing the low in 2005. The ice extent is now expanding as winter approaches.