By Alex Kirby BBC News Online environment correspondent

The dash for gas has helped the UK to close old coal power stations

But the fall followed two years during which greenhouse gas emissions actually rose, so it does mark some progress.

The EEA says the EU has taken a small step towards meeting its target under the Kyoto Protocol, the international agreement on tackling climate change.

But it warns the states concerned that they have much more to do if they are actually to meet their commitments.

Help from the elements

In a report, Annual European Community Greenhouse Gas Inventory 1990-2002 And Inventory Report 2004, the EEA says it estimates emissions from the EU's 15 pre-2004 member states fell by 0.5% from 2001 to 2002.

Only in Germany did road vehicle emissions not rise

Reasons for the decrease included warmer weather reducing the need for heating produced by the burning of fossil fuels, which gives off carbon dioxide (CO2), the most important of the six gases covered by the Kyoto Protocol.

Other reasons were slower economic growth in manufacturing industries, a continued shift from coal to gas, and specific measures undertaken to reduce emissions. In 2000 emissions of the six gases had risen by 0.2%, and in 2001 by 1.3%.

The 2002 fall took the total emissions from the 15 states which were then members of the EU to 2.9% below the baseline year used for calculations, in most cases 1990.

While this sounds positive, the EEA says, it means the EU is progressing more slowly than its Kyoto commitment demands.

Spain faces a greater challenge to meet its target than any other member state EEA report

That requires it to cut emissions to 8% below their 1990 levels by some time between 2008 and 2012.

The EEA says the 2001-2 cut of 0.5% "still leaves the EU with a long way to go to meet its commitment... Assuming the 8% reduction were to follow a linear path, emissions should have fallen by 4.8% by 2002."

On this basis, it says, only four countries are on track to comply with the national targets accepted by all pre-2004 EU members - France, Germany, Sweden and the UK.

The 11 other states are heading towards overshooting their targets, "some by a substantial margin".

Ways to catch up

The EEA says: "Spain faces a greater challenge to meet its target than any other member state. Its emissions in 2002 were 39.4% above their base year level - well over double the 15% increase it is allowed... under the EU agreement."

But the report says several initiatives could speed up progress towards the Kyoto target, principally the EU emissions trading scheme which starts next January.

A steaming Greek power plant: Most of Europe has much to do

Other measures which could help include the protocol's Joint Implementation provisions, which allow industrialised countries to invest in emission-saving projects in other developed countries, and the Clean Development Mechanism, which lets them make similar investments in developing countries.

Emissions from the 10 states which joined the EU on 1 May will not count towards the union's reduction target, although most of the 10 have their own targets.

The EEA report says emissions from road transport increased in 2001-2 in all of the 15 EU members except Germany.

The Kyoto Protocol has not yet entered into force, because it has not been ratified by enough signatories.

With the US, the world's biggest emitter of greenhouse gases, refusing to ratify it, the protocol's fate lies in the hands of Russia, whose intentions remain unclear.