Germany is set to miss its 2020 greenhouse gas emissions target by 8 percent, according to German weekly magazine Der Spiegel.

The German government set itself the goal of reducing national greenhouse gas emissions until 2020 by 40 percent compared to 1990 levels.

But a draft government report estimates that the country will only be able to reduce emissions by 32 percent. Officials had previously estimated a shortfall of 5 percent to 8 percent.

The document blames "unexpected economic developments and unexpected population growth" for the failure to meet the target. Increased economic activity and strong population growth generally cause an uptick in emissions due to increased use of fossil fuel energy.

"The climate protection report shows a gigantic gap between the government's words and deeds when it comes to climate protection," the German branch of the environmental protection group WWF said in a statement. "It's a 120-decibel alarm and the government has to show it has heard it."

Read more: Germany risks reputation with climate goals failure

Green Party leader lashes out at Merkel

Annalena Baerbock, co-leader of the Green Party, told Der Spiegel that the figures were proof Chancellor Angela Merkel, who has long championed the fight against climate change, "says a lot about the climate, but delivers very little."

The new figures came a day after the Organization for Economic Cooperation and Development (OECD) said Germany needed to do more to realize its climate change goals.

The OECD also cited strong economic growth as a challenge to meeting emissions targets. Traffic emissions had increased as well, it said, presenting another problem for the country's ability to meet its commitments.

Read more: Report details how emissions could peak by 2020

amp/sms (Reuters, dpa, AFP)