Pacific nations which are most under threat from rising seas have vowed to abandon diesel and other dirty, expensive fuels and replace them with clean sources of energy.
Using coconut biofuel and solar panels, Tokelau plans to become self-sufficient in energy this year.
The leaders of other small island states around the world made commitments at a meeting this week organised by the UN Development Program and the Barbados government.
The Cook Islands and Tuvalu are aiming to get all of their electricity from renewable sources by 2020.
Cook Islands Prime Minister Henry Puna told AFP he knows they have set ambitious targets, but he says they do not see those targets as being difficult.
He says about 15 per cent of the country's budget is spent on importing diesel oil, describing it a "crippling dependence".
UN studies show that oil imports account for up to 30 per cent of gross domestic product in some Pacific countries.
Ministers at this week's meeting complained in a statement that despite their "significant actions" to help ease global climate change, international action has been "slow and grossly inadequate," given the increasing threat to island nations from rising seas.
Their declaration - adopted ahead of next month's UN Conference on Sustainable Development in Rio de Janeiro - called for the new energy sources to be made "accessible, affordable and adaptable" so all threatened island states can take steps to adapt.