Inadequate national targets for curbing climate-altering greenhouse gases meant emissions would be "far above" the level required to stave off disastrous global warming, analysts warn.

Instead of the UN-targeted ceiling of two degrees Celsius of average warming over pre-Industrial Revolution levels, the world was on track for 2.9-3.1C by 2100, according to the Climate Action Tracker (CAT), a tool developed by a consortium of four research organisations.

"The climate targets so far submitted to the UN by governments collectively lead to global emissions far above the levels needed to hold warming to below 2C," a CAT statement said.

So far, 56 governments had submitted pledges, known as Intended Nationally Determined Contributions or INDCs, to a UN roster that will form the backbone of a universal climate-rescue pact to be inked in Paris in December.

Including major emitters China, the United States and the 28-member European Union, the pledges cover some 65 per cent of global emissions, and 43 per cent of the world population.

To stay under the 2C threshold, which scientists say is necessary to avoid worst-case scenario global warming, greenhouse gas emissions would have to drop from about 50 billion tonnes of CO2 equivalent (GtCO2e) per year today, to 39-43 GtCO2e in 2025 and 36-45 GtCO2e in 2030, according to the CAT.

Containing warming to an even safer 1.5C would require emissions of 38 GtCO2e in 2025 and 32 GtCO2e in 2030. The world has already warmed up by 0.8C — nearly half the 2C target.

"The current INDCs lead to emissions levels that exceed the benchmark 2C limit by 12-15 GtCO2e in 2025, and 17-21 GtCO2e in 2030," said the CAT statement.

The CAT based its analysis on an assessment of 16 pledges representing 64.5 per cent of global emissions in 2010, and 41 per cent of Earth's population.

Current targets for 2030 would make the 2C goal "almost infeasible", it found.

The level would instead be closer to "2.9-3.1C by 2100," Bill Hare of Climate Analytics, a CAT contributor, said.

Indonesia promises to cut emissions 29pc by 2030

Meanwhile, Indonesia has unveiled an ambitious new target for reducing carbon emissions, promising to slash its greenhouse gas output by 29 per cent by 2030, the government announced.

The increased commitment by one of the world's largest greenhouse gas emitters will be officially submitted to the UN later this month ahead of the major climate change summit in December.

"We have reached the decision to reduce [emissions] by 29 per cent by 2030," environment and forestry minister Siti Nurbaya Bakar said.

The pledge goes beyond Indonesia's 2009 agreement to slash emissions by 26 per cent — or 41 per cent with international assistance — by 2020.

The final draft submission states Indonesia has set aside 31.4 million acres of forest for conservation to help realise its target.

The government also hopes to derive nearly a quarter of its vast energy needs from renewable sources within a decade.

"Beyond 2020, Indonesia envisions an even bolder commitment to emission reductions," said the draft submission distributed by the ministry.

AFP