LE BOURGET, France >> Since Prime Minister Narendra Modi came to power, President Barack Obama has not missed many opportunities to convey what a warm rapport he has forged with the Indian leader.

There was the admiring essay about Modi that Obama wrote in Time magazine, and the image of them tête-à-tête at the Martin Luther King Jr. Memorial in Washington, their entourages left behind. Obama’s national security adviser said the two men had “chemistry,” and expressed confidence that American interests made it “worth the investment in the relationship.”

Exactly how much that investment has paid off will become clear this week during the climate negotiations on the outskirts of Paris, where India, the world’s third-largest greenhouse gas polluter, has emerged as a pivotal player in shaping the outcome of a deal on which Obama hopes to build his legacy — or whether a deal emerges at all. So far, Indian negotiators have publicly staked out an uncompromising position.

India embodies a critical tension that will play out in Paris between developed nations like the United States, which are calling for universal emissions cuts, and developing nations like India, which say they deserve to increase fossil fuel use as their economies grow or else receive billions of dollars to transition to cleaner energy.

After Modi met Obama on Monday — their sixth meeting in 14 months — he told reporters that the two leaders had “such a deep relationship that we are able to openly discuss all issues,” and said that he was happy to work “shoulder to shoulder with the United States.”

But in an earlier speech Monday, Modi said climate change was not India’s fault, and blamed it firmly on “the prosperity and progress of an industrial age powered by fossil fuel.”

“But we in India face its consequences today,” he said.

That India has positioned itself as the champion of developing nations is no great surprise, based on past climate talks. But Modi, who wrote an e-book presenting the moral case for action on climate change, had been seen by U.S. policymakers as a leader who might break that pattern.

“I think Obama got carried away with Modi, frankly,” said Jairam Ramesh, a leader of the opposition Indian National Congress party, who served as minister of the environment under the previous government. Modi has made one major breakthrough in talks with Obama, Ramesh said, committing “against the advice of everyone in the system” to limit the use of hydrofluorocarbons, or HFCs, a component in refrigerators and air-conditioners. Since then, he said, India’s negotiators have returned to their familiar, confrontational manner.

“India is not an easy country to negotiate with. We are moralistic, we are argumentative, we are regressive,” Ramesh said. “It has gone back to the old rhetoric, there is no doubt about it.”

India was the last major economy to submit its plans for a domestic climate change policy ahead of the Paris talks. And the proposal, while it included a significant expansion of renewable energy, would also see India’s carbon pollution triple in the coming decades. Indian officials have painted that projection as a concession, saying that in a business-as-usual scenario, their emissions would soar at an even higher rate.

Leaders in New Delhi argue that limiting coal use would cripple the economy and harm a population struggling to escape poverty, including 300 million Indians who live without electricity. They also say India has done little to contribute to the problem of global warming: India’s annual per capita carbon dioxide emissions are 1.7 tons, compared with 16.6 tons per person in the United States and 7.4 tons per person in China.

During the climate change talks, India is expected to challenge the United States on three counts: To speed up emissions reductions by wealthy countries to compensate for emissions growth in poor countries; to pay more to poor countries to assist in mitigation plans; and to provide clean-energy technology to poor countries.

Ashley Tellis, a senior associate with the Carnegie Endowment for International Peace, said Obama had “tried hard” to persuade Modi to shift India off those more hard-line negotiating positions before the climate talks, “but failed.”

“I still think that if the U.S. position comes to enjoy a strong consensus in Paris, India will not come in the way, but this acquiescence will materialize only at the last moment,” Tellis said. He said that Obama, in his talks with Modi, should have focused on the more modest goal of ensuring that India would not block a consensus.

The administration quickly disputed that contention.

“In our view, It has been very clear from Prime Minister Modi’s messages, including in his meeting with the president today, that India is committed to an ambitious Paris agreement that protects the planet while promoting the development and growth of countries like India,” said a White House official who spoke on the condition of anonymity because the negotiations were ongoing.

Knowing Modi’s position, the Obama administration has been working to reduce the tensions with India and the developing world without significantly increasing taxpayer spending.

In a move that appeared explicitly intended to win India’s cooperation in Paris, Bill Gates, the Microsoft founder and billionaire philanthropist, joined the Obama administration to create what is being called the largest-ever public-private coalition for funding renewable energy. The coalition has the cooperation of 20 countries, including the United States and India, which have pledged to double their funding of renewable energy research, and will feature a renewable energy research fund paid for by 28 billionaire philanthropists, including two prominent Indian businessmen.

The plans for the fund came together after French President François Hollande, who is deeply invested in the success of the Paris talks, invited Gates and Modi to meet on the sidelines of the United Nations General Assembly in New York in September. As Obama has tried to find ways to bring Modi into a deal, his officials have worked closely with Gates.

Hollande in the meantime worked with Modi on another initiative: a 121-nation solar energy alliance, which Modi unveiled Monday in the conference’s Indian pavilion.

Some analysts caution against overreacting to India’s negotiating postures — or, for that matter, its projections for expansion in its coal sector, which is dogged by corruption and inefficiency.

“We’re seeing them put forth their national interest, but you’re also seeing a willingness to negotiate,” said Jennifer Morgan, an expert on international climate change negotiations with the World Resources Institute, a research organization. “They’re staking out the priorities for their country. They know they’re not going to get everything they need, but they’re going to fight hard. This is classic positioning.”

Morgan predicted that India would engage in hard-line brinkmanship into overtime sessions of the climate talks, but that ultimately Modi does not want a deal to collapse.

Some Indian leaders expressed concern that India’s contributions to climate efforts could be eclipsed by negotiators’ adversarial tone. “I really believe that Modi wants to be remembered as the person who turned India green,” said Anand Mahindra, the chairman of the Mahindra Group, who has joined an international group of corporate leaders calling for carbon pricing at the talks.

“He is trying to take the lead as a green warrior,” he said of Modi. “He is being held back by this old reflexive rhetoric.”

Mahindra may be an outlier, though. Domestic audiences, on both the right and the left, are eager to see Modi and his environment minister, Prakash Javadekar, demonstrate influence in the international arena by standing up to pressure from Europe and the United States and demanding financing for green energy.

Monday’s editions of India’s major newspapers carried editorials from prominent figures urging negotiators to stand their ground, even at the cost of being labeled obstructionists or spoilers.

“The more criticism India comes under in Paris, the more applause Javadekar will get in Parliament and elsewhere,” said Ramesh, the former environment minister. “This is the dichotomy of the situation.”