HONG KONG (AP) — China will stick to its goal of having its carbon emissions peak by 2030 and will release more complete reduction plans soon, the country's climate change envoy said Tuesday, even as U.S. and British officials urged it to do more to limit global warming.

Envoy Xie Zhenhua said in an online webinar on climate change that China will release updated plans to reduce emissions soon and elaborate on its plans during a U.N. climate change conference in Glasgow, Scotland, later this year.

China has said its carbon emissions should peak by 2030 and then decline, with a goal of reaching carbon neutrality by 2060. The country, the world's largest carbon emitter, has argued that it is still a developing economy and should not be held to the same standards as developed countries in reducing carbon emissions.

World leaders and climate negotiators are to gather in Glasgow in November for the 26th U.N. Climate Change Conference of the Parties summit, where nations will attempt to agree on carbon emission reductions to keep global warming within 1.5 degrees Celsius (2.7 Fahrenheit) to prevent catastrophic effects from climate change.

The former U.S. special envoy for climate change, Todd Stern, said at the same webinar, organized by The Hong Kong University of Science and Technology and the think tank Our Hong Kong Foundation, that China has not announced plans to do enough in the 2020s.

"Peaking (carbon emissions) by 2030 in China cannot get the job done, and I don't think it represents a best effort to hold to 1.5 degrees Celsius," Stern said. "Nor is China's substantial planned expansion of its coal fleet in its 14th Five-Year Plan compatible with what needs to happen."

Stern said that what China does or does not do at home has a huge impact, not just on its own future but on the entire world, and that China's global standing and reputation could be significantly damaged if it is seen as the main reason why the goal of keeping global warming within 1.5 degrees Celsius is not kept alive.

Lord Adair Turner, chairman of the U.K. Energy Transitions Commission, urged China to have its emissions peak before 2030 and achieve zero carbon emissions by 2050 — a decade earlier than its goal — as by then it will be a rich, developed country.

"I think we need to face a simple mathematical fact that if China does not peak emissions until 2030, I do not think we have anything like a 50/50 chance of limiting global warming to 1.5 degrees Centigrade (Celsius), nor a 90% chance of keeping global warming below two degrees Centigrade," Turner said.

China's Xie said countries have different national conditions, stages of development and historical responsibilities, and that China has a larger proportion of coal as a natural resource and less oil and gas.

He said developed countries have already gone through industrialization for more than 200 years and are allowed longer timeframes to go from peak carbon emissions to carbon neutrality compared to China.

"It is estimated the European Union would need some 60 years in its transition from carbon peak to neutrality or net zero emissions, and the U.S. would need 45 years, while China will strive to achieve this goal in about 30 years," Xie said.

"Therefore, in such a short period of time, China still faces many difficulties and challenges to achieve this," he said. "This is a process, it cannot be achieved all of a sudden."

Xie urged countries to work together to implement their commitments instead of arguing whether the goal should be to keep global warming to 1.5 or 2 degrees Celsius.