A new website measures the CO2 impact of manufacturers in terms of a sales-weighted assessment of its products. The methodology does not address the CO2 incurred by the manufacturers in making their products and the sales weighting is for the UK market only.

The website’s publishers says that they have published their data which has has correlated the sales of every car in the UK to its official CO2 output for the benefit of the public and to enable a more informed debate.

Fiat, a small car specialist, emerges as the best performer.

Comments Jay Nagley, publisher of www.cleangreencars.co.uk, “People can assume that manufacturers of hybrid cars must be the best, but the truth is more complex. Making lots of efficient modern diesels actually has a bigger impact on CO2 performance than making a few hybrids. The top three marques are all pioneers of modern diesel engines while Toyota, although much better than average, is not absolutely the best.”

Another figure worth noting is that the most improved manufacturer in terms of CO2 performance is MINI, which has seen a remarkable 14% drop in CO2 emissions in the last year, thanks to a new range of ultra-efficient engines. The results also show why premium German manufacturers have opposed the 130 g/km CO2 target of the EU – their averages are all over 175g/km of CO2 (although they have recently announced programmes to cut CO2 outputs significantly).

However, the results demonstrate that the pace of improvement is currently very slow. While every manufacturer is working on reducing CO2 emissions, this table shows how vital it is to speed up progress.

The CO2 performance of every significant* car manufacturer was calculated in both 2006 and 2007. The calculations were carried out in association with Spyder Automotive, a leading supplier of analysis and forecasting to the car industry. The methodology was to take the CO2 figure for each type of car sold and weight it by the number of examples sold. Hence a Focus 1.6 Zetec (159 g/km CO2 and 4402 sales, Quarter One 2007) has a much bigger influence on the overall Ford figure than the Focus 2.5 ST2 (224 g/km CO2 and 808 sales, Quarter One, 2007)

*To count as significant, a manufacturer had to sell at least 1,500 cars in the first quarter of 2007 – hence small manufacturers such as Lamborghini (or Proton, for that matter) were excluded.

For the full table, visit www.cleangreencars.co.uk.