BEIJING — President-elect Donald J. Trump has called climate change a hoax created by China and said he would cancel an international accord to curb greenhouse gas emissions. But leaders of other nations, including China, are rolling up their sleeves for the hard work of putting that deal into practice.

The accord, an ambitious global effort signed in 2015 and known as the Paris agreement, rests on a foundation of transparency and good faith: Countries are supposed to report and submit for verification their carbon emissions data. Without accurate and timely reporting, there is no way to monitor progress and adjust policies.

China, the world’s biggest polluter, has refused to accept international monitoring of its emissions and says it will provide data to outside observers. In the past, conflicting data about the country’s energy use has raised questions about accuracy.

To take on a leadership role to promote the Paris agreement, as China has indicated it wants to do, Beijing will have to be more transparent on emissions. What exactly would it have to do?

The work of creating an international “transparency regime” has already begun. At a summit meeting in Marrakesh, Morocco, in November, officials discussed a plan to establish standards and mechanisms for reporting. Over the next two years, negotiators will engage in “the most technically complex and politically contentious issues,” said Li Shuo, a Beijing-based climate policy analyst at Greenpeace East Asia.

But China, he said, “still has a long way to improve its transparency system.”

International negotiators are expected to draw up standards that will apply to both developed and developing countries, unlike the bifurcated reporting requirements of older climate deals. This means that China and India will be compelled to provide the same kinds of information that, say, France and Japan do.

A country’s greenhouse gas output is determined by extrapolating data about energy use rather than directly measuring it. Accurate annual coal consumption statistics are critical for these calculations because industrial coal burning is the biggest source of greenhouse gas pollution.

But China’s coal statistics are subject to official corrections and changes, and updates are released just once every five years, when the country conducts an economic census.

The last census revealed that China’s coal-derived energy use was 12 percent to 14 percent higher than previous estimates for every year since 2005. Furthermore, there are persistent differences between coal consumption statistics reported on the provincial and national levels.

“Over time, it would be desirable if the reporting systems are improved,” said Glen Peters, a scientist at the Center for International Climate and Environmental Research-Oslo. “The fact that the census leads to 10 percent revisions in such an important commodity is a little worrying.”

“The U.S., for example, also has revisions, but generally less than 1 percent in the first year and maybe 0.1 percent in following years,” he said.

Another problem is that China has been reluctant to release its own calculations of emissions, so other nations rely on calculations made by foreign scientists.

The Chinese government has submitted emissions estimates to the United Nations only twice, for 1994 and 2005. Most other developing nations have also submitted only two estimates, but some, including Brazil and Mexico, have submitted three or more.

There is “no good reason” China is dragging its feet, said Mr. Li, the Greenpeace analyst.

Under the Paris agreement, countries will have to submit estimates every two years. “International forces are quite attractive in terms of putting pressure on improving the transparency system,” Mr. Li said.

At a news conference in Beijing in November, Xie Zhenhua, a special envoy on climate issues, said that although he believed China’s data was accurate, China was still a developing nation and struggling to establish the same type of reporting and verification systems that developed nations used.

“It was mentioned in the Paris agreement that a greater degree of flexibility should be offered to developing countries, and, first of all, funding and technical support should be provided to them to help improve their capacity,” Mr. Xie said.

“How to establish a system of transparency should only be considered on this basis,” he added. “China is also in such a phase of development.”

China will compile emissions data from four data sources: national and provincial governments, businesses, and a planned cap-and-trade carbon market, said Chai Qimin, a senior director at the National Center for Climate Change Strategy and International Cooperation.

The different areas of reporting “can be used to check against one another,” he said. “At least major discrepancies won’t happen.”

Mr. Chai and other climate researchers and policy advisers played down how large the carbon market would be by the end of 2017. They said Chinese officials had said only that the market would “launch,” not be fully operational.

China has been experimenting with seven regional pilot cap-and-trade markets. Mr. Xie, the climate envoy, said that as of September, the cumulative total turnover of carbon dioxide in those pilot markets was 120 million metric tons, and the cumulative transaction amount had exceeded 3.2 billion renminbi, or $473 million.

But some experts say a carbon tax would be a better way of putting a cost on carbon. Other scholars say the pilot programs have suffered from operational problems that could bode ill for the national market.

“I estimate that it will surely be launched in 2017, although there will be many difficulties, and the progress is unlikely to be fast,” said Jiang Kejun, a senior researcher at the Energy Research Institute, part of China’s Economic Development Agency. “For it to truly play a vital role, I think we’ll have to wait until 2019 or 2020.”

In any case, researchers say, other market forces are helping for now. They expect coal consumption in China to remain flat or drop, as has been the trend in the past two years. That is mainly because of the slowing Chinese economy. China promised two years ago that it would have its greenhouse gas emissions peak in 2030 — a goal that experts now say will be easily met.

Some are even suggesting that emissions may have already begun to drop for the long term, though an emissions peak can be confirmed only years after it has happened.

Mr. Peters’s group estimated that carbon dioxide emissions from fossil fuel consumption and cement production in China fell 0.5 percent in 2015 from the year before. Those kinds of numbers have been a pleasant surprise for climate negotiators and researchers.

On Thursday, the Chinese National Energy Administration announced a plan for 2016 to 2020 in which the country would spend $360 billion on renewable energy sources and create more than 13 million jobs in that sector. A related coal plan forecast marginal growth in coal consumption, estimating that the amount consumed in 2020 would be 4.1 billion metric tons, a 3.5 percent increase over 2015.

But Mr. Li said the five-year energy plans constantly overestimated China’s energy needs. Greenpeace calculations show annual coal consumption dropped in 2016, he said, and “it is hard to see how a 100-million-ton growth of coal would be possible.”

Source: NYTimes