
The cleangreencars.co.uk survey revealed a drop of 4 per cent in the average carbon emissions of new cars sold in the UK through 2008, from 164.8g/km in 2007 to 158.7g/km.
Usefully, the survey was configured not just to average out the individual CO2 emission figures of each new car sold, but to show up individual improvements in each model rang and shifts in buying patterns. It revealed a noticeable sharpening in CO2 emission fall-off over the last quarter of 2008, with the average dropping by 5.1 per cent from 163.4g/km to 155.4g/km. This, the journal concluded, "has at least as much to do with the recession as it does an improvement in the CO2 output of the cars on sale, with buyers choosing smaller and more efficient models in the face of the economic downturn".
Mini topped the cleanest manufacturer list for the year at 137.24g/km (a 6.8 per cent improvement), just ahead of Fiat's 137.32g/km (3.45 per cent).
Most improved performer award went to Chrysler's Jeep brand, with average emissions dropping from 252.68g/km to 217.0g/km, a 14.1per cent gain the journal attributes to the arrival of the smaller, more fuel efficient Patriot and Compass.
BMW, Hyundai and Subaru also showed up as big improvers with double digit reductions.
Down the other end of the table were Land Rover and Chevrolet, both of whose emissions averages increased, albeit by less than 1 per cent apiece. Worst performer was another Chrysler brand, Dodge, whose emission average rose 8.3 per cent.
The UK's 10 cleanest manufacturers by CO2 emissions during 2008 (with percentage figures in brackets showing improvement over 2007 figures)...
Mini 137.24 g/km CO2 average in 2008 (6.8 per cent)
Fiat 137.32g/km (3.45 per cent)
Peugeot 140.16g/km (4.55 per cent)
Toyota 144.01g/km (2.86 per cent)
Citroen 145.40g/km (1.80 per cent)
Skoda 148.00g/km (2.23 per cent)
Hyundai 148.03g/km (10.09 per cent)
Daihatsu 148.62g/km (3.34 per cent)
Renault 151.91g/km (2.27 per cent)
Ford 152.34g/km (1.61 per cent)