TOKYO | Thu Apr 9, 2015 3:39am BST

Japan is considering reducing emissions of greenhouse gases by around 20 percent by 2030 as its contribution to a global summit on climate change in Paris later in the year, Japanese media reported on Thursday.

The target is lower than that outlined by the United States, which says it will cut emissions by as much as 28 percent from 2005 levels by 2025 and the European Union which is proposing at least a 40 percent cut from 1990 levels by 2030.

Japan is the world's fifth-biggest emitter of climate warming carbon dioxide, but has watered down earlier emissions targets due to the shutdown of its nuclear plants after the 2011 Fukushima disaster, with utilities burning record amounts of coal and gas for power generation.

Japan is considering a pledge to cut emissions by at least 20 percent by 2030, compared with 2005 levels, Kyodo News reported, citing sources close to the matter.

The Nikkei reported that the Japanese government will propose cutting emissions by about 20 percent by 2030 from 2013 levels, implying a slightly lower absolute reduction due to a later base year.

Japan has switched its baseline to 2013 from 2005, reflecting a rise in emissions following Fukushima, which would help make the cuts of around 20 percent more attainable, the Nikkei said.

Japan's greenhouse-gas emissions rose to a record in the year ended March 2014, up 1.3 percent from 2005, as the closure of nuclear power plants following the disaster pushed up coal and gas use.

Japan is aiming to announce its carbon emissions targets at the Group of Seven meeting in Germany in early June, and trying to finalize the breakdown for power generation mix for 2030 as early as this month as a basis for finalizing emissions targets.

The government is considering cutting the ratio of fossil fuel-fired generation in 2030 power mix to around 55 percent from about 90 percent now, which alone would cut emissions by around 15 percent from 2013 levels, the Nikkei report said.

The Paris summit starting in November aims to finalize an agreement as part of long-term efforts to limit average temperature rises to 2 degrees Celsius (3.6 Fahrenheit) above pre-industrial times.