Europe emitted 3.3 percent less Earth-warming greenhouse gases in 2011 -- the lowest level since 1990, a European Environment Agency (EEA) report said Wednesday.

The bigger-than-expected drop in the European Union from 2010 was equal to a saving of 155 million tonnes of CO2 equivalent, a measure of greenhouse gas concentration in the atmosphere, it said.

But the continent should not congratulate itself too much -- the decline was largely due to a mild winter with lower heating demand.

"The greenhouse gas emissions cut in 2011 is good news, however it was largely due to a warmer winter," EEA executive director Jacqueline McGlade said in a statement.

"Nonetheless, the EU is making clear progress towards its emissions targets" of cutting greenhouse gases by 20 percent on 1990 levels by the year 2020.

On the downside, the report noted a rise in consumption of carbon-intensive fuels such as coal, while 'greener' hydroelectricity production, natural gas consumption and nuclear power use decreased.

"If Europe is to achieve the transition towards a low-carbon society, it will need sustained investment in technology and innovation," said McGlade.

The report said early estimates by the EU statistics agency Eurostat, also released Wednesday, pointed to a 2.1 percent drop in greenhouse gas emissions for the bloc in 2012.

With the 2011 figures now in, the EU had cut its emissions by 18.4 percent from 1990 -- a reference year chosen by the international community.

This amounted to more than a billion tonnes of CO2 equivalent, said the statement, and seemed to place the bloc well on the way to achieving its 2020 target.

The EEA said fossil fuel consumption decreased by five percent in the EU in 2011, but carbon intensity of emissions increased with a near two-percent rise in use of solid fuels like hard coal and lignite.

Liquid fuel consumption decreased by four percent and natural gas by almost 11 percent while renewable energy use showed its second-largest decline in the last 21 years.

While wind and solar energy use continued to rise, nuclear power declined mainly due to the closure of plants in Germany.

Road transport emissions declined for the fourth year in a row, but emissions from international aviation and shipping rose in 2011, said the agency.

The EU bloc has repeatedly dismissed calls, mainly from developing countries, to raise its emissions curb target to 30 percent by 2020.