Indian Prime Minister Narendra Modi, shown with Germany’s Angela Merkel in Berlin, says failing to act on climate change would be “morally criminal.” (John MacDougall/AFP/Getty Images)

As the United States pulls back from its commitment to fight climate change, the world’s two other biggest polluters — India and China — are sounding the alarm. But neither country is in a position to fill the void left by American leadership, or to foot the bill.

Their vast populations stand to lose dramatically from global warming, and the two countries’ leaders are already taking a stronger public stance against the threat posed by carbon emissions in the form of rising sea levels and catastrophic weather patterns.

Both say they will honor their commitments to the Paris accord, and they are encouraging other countries to do the same. That sort of rhetorical leadership is very welcome, experts say, but neither country is in a position to replace the financial incentives the United States had offered poorer nations.

This week, Indian Prime Minister Narendra Modi, during a visit to Berlin, stood alongside German Chancellor Angela Merkel and said that failing to act on climate change was a “morally criminal act.”

(Daron Taylor/The Washington Post)

Earlier this year, Chinese President Xi Jinping called the 2015 climate accord in Paris “a hard-won achievement” and urged other signers to stick to their pledges instead of walking away — “as this is a responsibility we must assume for future generations.”

In the past, there was skepticism in both countries about Western calls for emissions reductions, which were seen as hypocritical. The strong public comments now underline how far opinion has moved in both countries .

In his announcement Thursday, President Trump sharply criticized both India and China, saying they had gotten preferential treatment when they signed the accord.

The Trump administration’s withdrawal from the pact, analysts say, jeopardizes financing for mitigation and control efforts by smaller nations and stokes fears that other countries may abandon their pledges to reduce emissions along with the United States.

It also dramatically undermines the chances of further progress in years ahead: The commitments contained in the Paris accord are not enough to prevent catastrophic rises in global temperatures, and much deeper emissions cuts would be needed. The U.S. withdrawal is bound to badly damage the accord’s credibility and the chances of keeping the rest of the world focused on the tough choices ahead.

“It’s a body blow,” said Chandra Bhushan, deputy director of the Center for Science and Environment in New Delhi. “People are putting on a brave face and saying it doesn’t matter if the U.S. withdraws from the Paris agreement. But it is built not only on cutting emissions, but finance and technology, and the U.S. contribution is about 20 percent of that.”

All but two countries are in the Paris climate agreement. The U.S. could be the third.

Japan’s environment minister, Koichi Yamamoto, said at a news conference Thursday that “I can’t help but feel concerned whether the Paris treaty without U.S. participation would be effective.”

Yet Yasushi Kimura, head of a major Japanese conglomerate of metals and petroleum companies called JXTG Holdings, told the Nikkei business newspaper when asked about climate change, “It’s hard to imagine not working on it just because the U.S. pulled out.”

The United States is the world’s second-largest emitter of greenhouse gases and had pledged in Paris to reduce its emissions 26 percent to 28 percent below their 2005 levels by 2025. The country’s withdrawal will have a major impact on the agreement’s goal of keeping the warming of the planet to below two degrees Celsius (3.6 degrees Fahrenheit) of what it was in preindustrial times, experts say.

Trump, who has said climate change is a “hoax” and that restrictions are bad for the U.S. economy, has already moved to roll back many Obama-era policies such as clean power, vehicle emission standards and curbs on power plants.

China and India had been slow to address the issue of global warming — fearing it would hold back the pace of development. In India for example, 240 million people remain without electricity.

But experts now predict that China’s carbon emissions will peak, and then begin to decline, significantly earlier than the country’s 2030 target, and the country is investing more in renewable energy than any other nation, pledging a further $360 billion by 2020.

“China will continue to carry out innovation, green, open and shared development regardless of how the other countries’ positions are changing, based on the inherent needs of its own sustainable development,” Hua Chunying, a spokesman for the Ministry of Foreign Affairs, said in a news conference this week in Beijing.

And now new energy policies in both nations are beginning to have a discernible effect, scholars say.

Slowing consumption in China and delay of construction of new coal plants in India is likely to reduce projected global emissions by 2 billion to 3 billion tons by 2030, compared with forecasts from last year, according to a study released in May by Climate Action Tracker, an independent monitoring group.

Meanwhile, India — which set a target of increasing its renewable power capacity to 175 gigawatts by 2022 — has exceeded its targets for wind power this fiscal year and has made some strides in increasing its solar capacity, according to a study from the World Resources Institute. Recent low solar prices may make renewable power increasingly competitive, the study said.

In addition, the country is holding off on the construction of some new coal-fired power generating plants because the extra capacity may not be needed for now, according to a new draft electricity plan.

Piyush Goyal, India’s energy minister, said that India remains committed to its Paris pledge — no matter what happens in the rest of the world.

“We are not addressing climate change because somebody told us to do it, it is an article of faith for this government,” Goyal said. “Sadly the developed world does not show the same commitment to fulfill their promises, which could help speed up the clean energy revolution.”

Yet neither country is willing to foot the bill for other countries’ efforts to reduce emissions, experts say. The United States had pledged $3 billion into a Green Climate Fund to assist smaller countries on their climate change initiatives — $2 billion of which has been canceled by the Trump administration.

Zhang Zhongxiang, the director of the China Academy of Energy, Environmental and Industrial Economics and a professor at Tianjin University, said China is more likely to take a role of a “cooperator” and “pusher” rather than assuming the out-front leadership role the Obama administration adopted. Zhang said China may contribute financially in smaller ways, such as contributing $20 million to its South-South Cooperation Fund to help smaller countries.

The two countries are likely to foster knowledge sharing with other nations, rather than creating super funds, such as India’s founding of International Solar Alliance — a knowledge platform for sun-rich countries — with France in 2015, said Varad Pande, a former adviser to India’s Environment Ministry and a member of India’s climate negotiations team.

“It will be a different flavor of leadership,” Pande said.

Denyer reported from Beijing. Shirley Feng in Beijing and Anna Fifield in Tokyo contributed to this report.