A team of Pacific youth representatives who are in Durban for the global climate summit says delaying a deal on carbon emissions puts more pressure on small island countries.
Governments at the COP17 summit are negotiating a road map towards a legally-binding agreement on reducing emissions.
Many countries want this to be in place by 2015 but it's uncertain whether the US and China will commit.
Aaron Packard, who is part of the Pacific team lobbying leaders about the destruction of sea-level rise and other climate patterns on Pacific islands, says dragging the chain on the issue is destructive.
"Delaying the decision until 2020 effectively means locking in at last four degrees of average warming around the world. Tuvalu and Tokelau have just come out of a state of emergency because they literally ran out of water. And that risks becoming the new reality for the Pacific region."