Opec members Iran and Saudi Arabia, the top greenhouse gas emitters yet to submit national strategies for tackling climate change, say they will do so before a UN summit in December in a sign of widening participation even by oil producers.
More than 150 governments of almost 200 nations worldwide have issued plans to curb greenhouse gas emissions - mainly from fossil fuels - and adapt to changes such as more heat waves, floods, or storms, meant as the building blocks for a deal at the summit in Paris from November 30 to December 11.
At a final round of UN talks in Germany to prepare the deal, delegates from Opec members Iran, Saudi Arabia and Nigeria, as well as other outsiders including Pakistan and Egypt, said they would all submit plans before the Paris meeting.
Those submissions would push the global total of emissions covered by national plans to more than 90 per cent from 87 per cent by an informal UN deadline of October 1, and calm concern that Opec will stay on the sidelines of a plan that threatens fossil fuel use.
"There is a sense that everybody is on board. I think that's a major shift and bodes quite well for Paris," said David Waskow of the World Resources Institute (WRI) think-tank.
Even so, many national plans for action beyond 2030 are vague.
"There's no agreement among Opec to be slow on this - no common position," said Emmanuel Oladipo, a member of the Nigerian delegation. He said Nigeria, which has worked to curb gas flaring, would soon issue a plan.
The UAE became the third Opec member, after Algeria and Ecuador, to submit a plan, saying it would initially raise the share of nuclear and renewables in its energy mix to 24 per cent by 2021 from 0.2 per cent in 2014.
Iran, the world's number 10 greenhouse gas emitter and the biggest not to have submitted, said it would be able to do far more to curb emissions if Western powers quickly lift sanctions imposed over its nuclear programme.
"The lifting of these unjustifiable and unjust sanctions would have a significant impact on what we are likely to achieve," said Majid Shafie-Pour, head of Iran's delegation in Bonn, Tehran aimed to issue the plan in mid-November.
Saudi officials also confirmed that their country, the number 14 emitter on a WRI ranking, would submit a plan before Paris. They declined to give details.
"The wide participation is very encouraging," said Elliot Diringer of the US Center for Climate and Energy Solutions.
An Egyptian delegate said the country was planning increased use of renewable energies, a phase-out of fossil fuels and improved public transport.