BEIJING -- China, the world's largest carbon emitter, launched on Tuesday its first trading scheme aimed at reducing emissions, an official said.

A platform allowing businesses in the southern city of Shenzhen to trade carbon emission permits held an official launch ceremony and has completed several trades, a spokeswoman for the city's foreign affairs office said.

Under the trading scheme, companies will be assigned an emissions quota and will be able to profit from selling excess permits to other firms if they are below their quota, reports said.

China plans to open similar schemes in a total of seven areas including the capital Beijing, the major commercial center of Shanghai, the port city of Tianjin and Guangdong province before 2014, in what analysts say is a step towards a nationwide carbon market.

The pilot programs will cover areas in which tens of millions of people live and cover far more emissions than the entire carbon market in Australia. They also come as the European carbon trading market has collapsed while Australia's could be scrapped depending on the outcome of national elections later this year.

"This is the first step towards a national carbon trading system," said Li Yan, head of environmental group Greenpeace's climate and energy campaign in China.

But analysts have said that the scheme, which covers just 38% of the city's emissions, is unlikely to produce significant emissions reductions.

"It only covers less than half of the city's emissions, so the effectiveness in terms of carbon cuts needs to be seen," Li said.

"To me the pilot is necessary homework to get the country prepared on its capability to manage carbon."

Because of its reliance on coal and heavy industry, China has emerged as the top producer of climate-changing carbon emissions, ahead of the United States, though its per capita emissions remain far below the U.S.

China has no targets to reduce absolute carbon emissions and government officials have said they will continue to rise until around 2030.

Beijing is aiming by 2020 for a 40% reduction from 2005 levels of carbon intensity, a measure of the amount of carbon produced per unit of economic output.

Copyright Agence France-Presse, 2013