China's pledge to zero out its emissions of carbon dioxide could cut the expected rise in global temperatures this century by up to 11%, the largest single reduction ever estimated by the Climate Action Tracker, which monitors progress under the Paris Agreement on climate change.

President Xi Jinping of China told the United Nations Sept. 22 that his country aims to halt the rise in its carbon emissions before 2030 and to become carbon-neutral by 2060. The announcement was a "milestone," according to the Climate Action Tracker, or CAT, because it marked the first time that China acknowledged the need to eliminate carbon emissions by midcentury.

If China makes the pledge a formal commitment under the Paris Agreement and succeeds in reaching the target, the pact would limit the increase in global temperatures to 2.4 to 2.5 degrees Celsius by 2100, CAT estimates, compared to an increase of 2.7 degrees Celsius without a net-zero China.

Though the Paris Agreement's ultimate goal of limiting the rise in global temperatures this century to 1.5 degrees Celsius would still be out of reach, China's announcement is "very welcome as it requires a rethink of all infrastructure investments that will last for decades," said CAT, which is headed by the nonprofit NewClimate Institute and Climate Analytics, a science and policy analysis firm.

"With this announcement, the world's largest carbon emitter finally shifted from its long-term position of having limited responsibility to reduce global emissions as a developing country, to assuming clearer leadership in tackling climate change," said Alex Whitworth, research director at consultancy Wood Mackenzie.

The path to zero emissions, however, is not yet clear, said Prakash Sharma, head of markets and transitions for the Asia Pacific at Wood Mackenzie. China has not yet stopped its construction of new coal-fired power plants, which are built to run for decades, Sharma noted.

'A green revolution'

Xi connected China's decision to pursue carbon neutrality to the world's experience with the coronavirus pandemic, saying the health and economic crisis "reminds us that humankind should launch a green revolution and move faster to create a green way of development and life."

That aligns with the approach of the European Union, which has made a "green recovery" from the pandemic-caused shutdown a priority.

While many countries still are not prioritizing climate or the transition to low-carbon energy in their COVID economic recovery plans, Adair Turner, co-chair of the Energy Transitions Commission, said the financial response from the European Union, in particular, has "a significant element of green reinforcement."

Among the big unanswered questions are China's definition of carbon neutrality and exactly how the country plans to achieve it.

Gener Miao, chief marketing officer at solar-panel maker JinkoSolar Holding Co. Ltd., told analysts Sept. 23 that China's government is drafting a five-year plan for 2021 that is expected to raise a target for "nonfossil energy consumption" to 20% by 2030.

Turner, of the Energy Transitions Commission, said there is still "a big debate to be won" in China.

"The challenge in China is that every time the Chinese economy slows down, the tool that the Chinese policymakers know how to stimulate the economy with again is construction," Turner said at Climate Week on Sept. 21, the day before Xi's announcement. And that is "very, very carbon-intensive."