Paris (AFP) - The UN warned Friday that nations' carbon-cutting pledges go nowhere near far enough to prevent dangerous global warming, as political efforts gain speed three weeks before a Paris summit tasked with sealing a climate rescue pact.
National pledges to curb greenhouse gas emissions -- if respected -- would yield only a third of the cuts needed by 2030 to keep Earth from overheating, according to a UN Environment Programme (UNEP) report.
The voluntary targets "are not sufficient to limit global temperature rise to the recommended level of two degrees Celsius (3.6 degrees Fahrenheit) this century," UNEP Executive Director Achim Steiner said in a statement.
This is a threshold beyond which scientists say the Earth will be racked by intolerable drought, superstorms, mass migration and a land-gobbling rise in sea levels.
Emissions reduction plans submitted by nearly 150 nations so far would result in a temperature hike of 3.0 C (4.8 F) or more by 2100, the UNEP said.
Other scientific analyses of these Intended Nationally Determined Contributions, or INDCs, have varied between 2.7 C and 3.5 C.
The UNEP's annual "Emissions Gap" report tracks the difference between projected carbon dioxide pollution on the one hand, and the levels required to stay under 2 C on the other.
This year's report is the first to take into account emission cuts promised by nations ahead of the November 30-December 11 Paris summit, tasked with delivering the first-ever universal climate pact.
- 'Far from enough' -
Without the INDCs, annual greenhouse gas emissions would reach about 60 billion tonnes of carbon dioxide equivalent -- a measure that groups greenhouse gases such as methane and nitrous oxide -- in 2030.
Last year, the figure was 53 billion tonnes.
If they are honoured, the INDCs would shave off six billion tonnes for a total of 54 billion tonnes in 2030, said the UNEP.
But in order to not pierce through the 2 C ceiling, total emissions in 2030 should not exceed 42 billion tonnes, according to the UN's climate science panel.
"The submitted contributions are far from enough, and the emissions gap in both 2025 and 2030 will be very significant," the new report said.
Ministers from more than 60 nations gather in Paris from Sunday to Tuesday to discuss political impediments to increasing INDC ambition.
They will tackle make-or-break issues such as climate finance for poor nations to make the shift from cheap and abundant coal, oil and gas to renewable energy sources, and to shore up defences against climate change-induced damage.
The ministers will seek to identify areas of possible compromise ahead of the highly-anticipated Paris conference, to be opened by more than 80 heads of state including US President Barack Obama, China's Xi Jinping and Narendra Modi of India.
- Green money -
The UNEP report highlighted that the time to act is now.
Greenhouse gas output will still be on the rise by 2030, it said, while many scientists believe it should drop to near zero by 2075 at the latest.
Last week, the UN's climate body said INDCs placed humanity on course to use up two thirds of the Earth's entire "carbon budget" -- the amount we can emit without overshooting 2 C -- already by 2030.
Both reviews took into account the 146 INDCs submitted to the UN by October 1, including all developed nations and three quarters of developing ones.
Collectively, they cover some 88 percent of the world's greenhouse gas emissions.
Many of the pledges from developing countries, such as India, were contingent on receiving financial support, one of the most divisive issues.
The UN Green Climate Fund said Friday it had approved its first financing -- $168 million (155 million euros) -- for projects to help poor nations adapt to the impact of climate change.