China should manage its massive urbanization plan in a low-carbon way to alleviate growing pressures on the environment and resources, a report said.

"Low-carbon urbanization is an effective way to control greenhouse gas emissions, which will be the major task for the country in the coming decades," Wang Weiguang, chief editor of the report Green Book of Climate Change, said on Monday.

China plans to cut carbon emissions relative to GDP by 40 to 45 percent by 2020, compared with 2005 levels.

In order to reach the target, low-carbon development is necessary, said Wang, who is also head of the Chinese Academy of Social Sciences.

Low-carbon development means a minimal output of greenhouse gas emissions, which cause climate change.

Statistics show China emitted more than 9.2 billion tons of carbon dioxide in 2012, nearly 27 percent of the world's total.

The figure may continue to grow in the coming years due to the country's massive urbanization, said Zhuang Guiyang, a researcher of the Institute for Urban and Environmental Studies under the Chinese Academy of Social Sciences.

He quoted a report from McKinsey & Company saying that China's urban population will hit nearly one billion by 2025, which means the country will have 221 cities with at least one million inhabitants and 23 cities with more than five million. "Without proper management, such booming urbanization will be a disaster," Zhuang warned, adding that the country has already paid a high cost for its quick economic development.

In the past three decades, the country's urban population has soared to more than 700 million from less than 200 million, causing severe problems such as water shortages, more smoggy days and shrinking arable land.

"This development pattern is unsustainable, which should be avoided in the new period of urbanization," Zhuang said.

The report suggested authorities create a low-carbon urbanization plan, setting different carbon emission targets for different regions and giving priority to developing energy-saving industries such as clean energy and the service industry.

The report also said the country should build medium or small-sized cities, which will have better transportation systems and stable housing prices.