China aims to cut the amount of energy and carbon dioxide emissions needed for every unit of economic growth by 16 to 17 percent from this year to the end of 2015, Chinese Premier Wen Jiabao said on Sunday.

This was the first time a top Chinese leader had spelled out the nation’s energy and carbon “intensity” goals for its new five-year development plan.

China is the world’s biggest emitter of carbon dioxide, the main greenhouse gas from using fossil fuels that is stoking global warming. The goals for 2011-2015 set out by Wen are generally in step with the government’s pledge to cut carbon intensity by 40 to 45 percent by 2020, relative to 2005 levels.

The targets appear to be on the lower side of what some experts and officials have proposed, but Wen said they would nonetheless be demanding.