Average carbon dioxide emissions from new cars sold in the European Union fell 2.6 per cent last year, beating goals set for 2015 as part of efforts to slow climate change, the European Environment Agency (EEA) said on Wednesday.

Average emissions slipped to 123.4 grams of carbon dioxide per kilometre, below a 2015 goal of 130 grams that was already reached in 2013 with 126.7 grams, the Copenhagen-based EEA said in a report.

The most carbon-efficient cars were bought in the Netherlands, Greece and Portugal with the least efficient in Estonia, Latvia and Bulgaria, it said. The EU has set a goal of 95 grams per km by 2021 to help limit global warming.

"On past trends, we'd expect missions to keep decreasing," Martin Adam, head of the EEA unit for air pollution, transport and noise, told Reuters.

The 2014 decline was mainly because of more efficient cars rather than because Europeans, drained by years of recession or weak economic growth, could only afford small vehicles that burn less fuel, he said.

New car registrations in the European Union rose almost 6 per cent last year to 12.5 million, ending declines since a pre-recession peak of 15.5 million in 2007.

In January, the industry association AWEA said the 2014 rise was thanks to government incentives, tax breaks and a consumer shift to cheaper brands such as Dacia and Skoda.

Adam said the EEA data was only for the full year and could not tell, for instance, whether a sharp fall in oil prices in 2014 had swung buyers towards bigger, higher-emissions cars in recent months.

Adam said the EEA was trying to improve data collection because car emissions could be 20 to 30 per cent higher in real-world driving than in official car tests.

"There are so many variables. If you drive with the windows open, or with a roof rack, with the air conditioning on or heavily loaded with passengers ... it all affects emissions," he said.

Brussels-based environmental campaign group Transport & Environment said the EU tests exaggerated reductions in carbon emissions by carmakers, giving a false sense of progress.

"While on average new cars in 2014 achieve 5 litres per 100 km in tests (56 miles per UK gallon), on the road the car consumes closer to 6.5 - costing a typical motorist an extra 500 euros ($530) in fuel a year," it said. – Reuters