Indonesia has pledged to cut its greenhouse gas emissions by 29 percent by 2030 through stepping up protection of forests and boosting the renewable energy sector, but observers criticised the plan as lacking in detail.

Indonesia, one of the world's biggest greenhouse gas emitters, said it would reduce deforestation, restore degraded forests, and lift the share of renewable energy to almost a quarter of the national energy mix in a decade, according to the country's official UN filing.

The sprawling archipelago is home to vast tracts of tropical rain forest but much has been felled in recent years, to be sold as timber and to make way for palm oil and pulp plantations, greatly increasing the country's emissions.

The 29 percent reduction by 2030 is relative to a business-as-usual scenario without climate action, according to the pledge filed on Thursday, the latest to be submitted ahead of UN talks on a climate rescue pact in December in Paris.

With international assistance, such as financing, the pledge raises the target to a 41-percent cut by 2030. Previously in 2009, Indonesia had vowed to cut emissions by 26 percent by 2020.