German power plants have emitted more greenhouse gases in 2013 than last year despite the country's energy policy, a German newspaper reported Saturday.

"The energy-related CO2 emissions are estimated to increase in Germany by about 20 million tons," Frankfurter Allgemeine Zeitung quoted Hans-Joachim Ziesing, managing director of the Working Group on Energy Balances, a statistical agency in the industry, as saying.

The latest report published by the agency showed that CO2 emissions were 810 million tons last year.

The yearly increase changed the declining trend of greenhouse gas emissions since 1990, though Germany has produced more electricity from renewable energy resources under its policy.

Ziesing said the increase in emissions was caused by higher coal and oil consumption.

An annual UN climate change conference will start Monday in the Polish capital of Warsaw to discuss rising global CO2 emissions and the dangers it poses to the world. Representatives from 195 countries and regions will lay the foundation for a new climate treaty.