BEIJING -- China has been striving to fulfill commitments to reduce carbon emissions per unit of gross domestic product (GDP) by 40 to 45 percent from the level in 2005, an official with the top economic planner said Tuesday.

Xie Zhenhua, deputy chief of the National Development and Reform Commission (NDRC), told a press conference that the country's commitments to the world have a legally binding force as they were approved by the top legislature.

"No matter what difficulties we are going to encounter, those commitments must be honored," Xie said.

Besides the carbon emission target, China aims to raise non-fossil energy's share in its total primary energy consumption to 15 percent and raise forest growing stock by about 1.3 billion cubic meters by 2020.

By 2013, carbon emissions per unit of GDP dropped by 28.56 percent from 2005. In the first three quarters of this year, energy consumption per unit of GDP dropped by 4.6 percent from a year earlier and carbon emissions were down by 5 percent, data showed.

In September, the NDRC approved a plan that maps out major climate change goals to be met by 2020.

"The moves taken this year and the achievements demonstrated China's determination to combat climate change with concrete initiatives," he said.