Manufacturer CO2 performance revealed by Jay Nagley

Clean Green Cars has conducted a unique research programme into the CO2 performance of every car manufacturer operating in the UK. We did this by taking the official CO2 output of every model and correlating that figure to its sales in both the first quarter of 2007 and the first quarter of 2006. That enabled us to come up with an accurate average figure for every manufacturer by reflecting its sales mix: for example a Focus 1.6 Zetec (159 g/km CO2 and 4402 sales) has a much bigger influence on the overall Ford figure for 2007 than the Focus 2.5 ST2 (224 g/km CO2 and 808 sales).

The results might surprise some people: the manufacturer with the lowest average CO2 figure is Fiat, thanks to the large proportion of small cars and diesels that it sells. In joint second place are Peugeot and Citroen, traditionally leaders in diesel technology. In fourth place is Toyota: despite its high profile hybrid Prius, it does not sell enough of them to make a major difference to its corporate average.

In terms of who is making the most improvement, Mini stands head and shoulders above the rest. Thanks to its ultra-efficient new range of engines (and also, it should be said, because its old engines were notably inefficient), it has reduced CO2 output per car by 14% in just one year. Mini is likely to continue improving as the old engines are still being phased out and further improvements are made to new models - a Mini with just 100 g/km CO2 is likely within a couple of years. The second best improvement was made by Toyota (5.5%) as it has reorganised its European model range to concentrate on smaller cars. Toyota has dropped the MR2 and Celica sports cars and also the large Previa MPV, with the express intention of reducing CO2 emissions. In fact, Toyota is the first manufacturer to stop selling certain models purely because of their CO2 outputs.

However, the bad news is that the overall figure has barely changed - an improvement of just 0.3% is negligible. Consumers are still not moving down to smaller cars in significant numbers and car manufacturers have not introduced enough new models with major reduced CO2 outputs. To be fair to the car companies, it is not that they are ignoring the CO2 issue, but their research programmes are taking a long time to bear fruit. Considering that the average must reduce to 130g/km CO2 by 2012, there needs to be a step-change in performance. The manufacturers say a 20% cut in five years is achievable with new engine technology, but they need to get those new engines out of the laboratories and on to the road.