Rich nations responsible for the bulk of the heat-trapping gases mankind has spewed into Earth's atmosphere must provide cash if they want developing countries to make climate-saving cuts, India insisted Friday.

Developing countries are hamstrung by a poverty-reduction imperative mixed with the expense of energy from renewable sources like wind and water, Indian official Ajay Mathur told AFP at a UN climate summit in Paris.

He touched upon one of the issues most likely to sink the decades-old talks for a pact to stave off calamitous climate change: how to share responsibility between rich and poorer nations for braking greenhouse gas emissions.

"If we were to accelerate it (renewable energy) for climate change reasons, then the countries which put the largest amount of carbon dioxide up in the atmosphere... the higher cost of energy has to be met by them," said Mathur.

"It is because of the presence of that large amount of carbon dioxide up in the atmosphere that we are being told there is no longer a space for more coal use in India."

India is the world's third biggest emitter of greenhouse gases. It is widely seen as a potential blocker in the Paris negotiations, which cannot produce the hoped-for agreement if there is opposition from any major party.

Some delegates are concerned India's determined stance on contentious money issues could lead to a weaker agreement.

India pledged in the lead up to Paris to cut carbon intensity -- the amount of pollution per dollar of GDP -- by up to 35 percent by 2030.

But unlike the world's top two emitters, the United States and China, it balks at net carbon reduction and plans to double coal production by 2020.

- Energy poverty -

"Developing countries face a huge amount of development challenges. You need money for education, you need money for health, you need money for roads, so again there are tradeoffs," said Mathur, a senior official in India's state-run Bureau of Energy Efficiency and climate negotiator.

"We don't want to lock people into perpetual energy poverty and income poverty... People have to lead a worthwhile life on a worthwhile planet."

Mathur emphasised the emissions produced by an average Indian was "almost nothing" compared to a person in a rich nation.

"Even in 2030... each Indian would be producing emissions that are less than those from any developed country," he said.

India gets about six percent of its energy from renewables today.

The only way to expand it is to make renewable energy cheaper than that derived from coal, said Mathur.

- High costs -

Solar and wind plant developers in India face high interest rates, he said, translating into more expensive electricity.

"So the availability of capital, for example, to bring down the interest rate would be a very useful tool in accelerating our renewable energy programme," Mathur said.

Rich nations pledged in 2009 to muster $100 billion (92 billion euros) per year from 2020 to help developing countries shift away from fossil fuels and shore up their defences against climate change-induced harms.

Developing nations have expressed anger in Paris that architecture has yet to be put in place to guarantee those funds.

Developing nations also want assurances that the amount will increase over time, but rich countries are loath to make new, long-term commitments.

In a blog post on Friday, Greenpeace chief Kumi Naidoo said India could play a major role in shaping an ambitious Paris agreement, in keeping with its desire to raise people out of poverty.

"If India moves, in the process forcing richer countries to move too, then it will not just be campaigners like me who will be grateful to you, but billions of people not yet born," Naidoo wrote.

UN climate talks turn hostile over money
Le Bourget, France (AFP) Dec 3, 2015 - Angry developing nations warned Thursday that increasingly tense UN talks aimed at averting catastrophic climate change would fail unless a bitter feud over hundreds of billions of dollars was resolved.

Negotiators from 195 nations are haggling in Paris over a planned universal accord to slash greenhouse-gas emissions that trap the Sun's heat, warming Earth's surface and oceans and disrupting its delicate climate system.

Taking effect from 2020, the pact would target emissions from fossil fuels such as coal, oil and gas -- the backbone of the world's energy supply today -- as well as from the cutting down of rainforests.

The question of finance to help developing countries make the shift to cleaner energy sources is "make or break", said South African negotiator Nozipho Mxakato-Diseko, who spoke on behalf of the G77 group of 134 developing and emerging countries, plus China.

"It has to be clearly understood that finance is critical," she told a news conference.

At stake is hundreds of billions of dollars that would need to start flowing from rich to developing nations from 2020. However the developed nations have yet to fully commit to the financing deal.

With frustrations at the conference mounting, UN Secretary-General Ban Ki-moon called on the world's leading economies to honour the financing pledge they made at the last major climate summit six years ago.

"I have been urging the developed world leaders that this must be delivered," Ban told reporters at UN headquarters in New York. "This is one very important promise."

Of the $100 billion to be mobilised by 2020, $62 billion has been raised so far, he added.

More than 150 world leaders including President Barack Obama launched the talks Monday, seeking to build momentum for the tough negotiations ahead with lofty rhetoric about the urgency of the task.

But after three days of grinding discussions over a hugely complex 54-page draft pact, bureaucrats unveiled a document just four pages shorter and with vast stretches of text yet to be agreed.

- Frayed tempers -

By the end of a day of frustratingly slow negotiations, tempers frayed.

"I am deeply concerned. I'm out of words. I have been doing this for many years, and this is just not right," Bolivia's Juan Hoffmaister, representing the G77 and China, told fellow negotiators at an evening session.

At the heart of the dispute is a demand by developing nations that the rich shoulder the most responsibility for fighting global warming because they have emitted most of the greenhouse gases since the start of the Industrial Revolution.

But some rich nations point out that developing nations, particularly China and India, are now big polluters.

Norwegian negotiator Aslak Brun said they were grappling with "very hard lines on all sides".

"Pointing fingers at this point in time saying: 'you are to blame and we are the good guys', it doesn't help us. Collectively, we just have to really speed up," he said.

Ministers from around the globe will descend on Paris Monday to try to transform the draft prepared by diplomats into a universal accord to avert planetary overheating. The conference is scheduled to end on December 11.

- 'Unthinkable failure' -

French Environment Minister Segolene Royal said she was still confident warring sides would come together by December 11.

"It is normal for it to take a day or two for negotiations to get into gear," she told AFP.

"It is unthinkable to imagine failure."

At the core of the talks is the goal of limiting average warming to a maximum of two degrees Celsius (3.6 degrees Fahrenheit) over pre-Industrial Revolution levels.

Scientists warn time for action is running out, issuing ever-louder warnings that steadily growing carbon emissions will doom future generations to rising seas and worsening floods, storms and drought -- a recipe for hunger, disease and homelessness for many millions.

James Hansen, one of the world's foremost climate scientists, warned in an interview with AFP that even capping warming to 2 C was a massive risk.

"Two degrees Celsius warming above pre-Industrial would put us at least at the temperature of the last inter-glacial period. Sea level was six to nine metres (20-30 feet) higher then," he said.

"If we let ice sheets become unstable, the world may become ungovernable because the economic consequence would be so great."