As another batch of environmentally-friendly new models are unveiled at this year's Geneva Motor Show, JATO Dynamics has revealed how the growth of small, low-CO2 cars is driving down the average CO2 emissions across Europe.

Volume-weighted average CO2 emissions across all models and segments fell by 7.9g/km last year, with over half of all cars sold in Europe now emitting less than 140g/km. This reduction has accelerated, compared with 2008, which saw CO2 emissions reduce by 5.4g/km.

The majority of this decrease is being driven by shifts in buying habits towards smaller, low-CO2 cars, with the three lowest CO2 bands increasing market share, at the expense of bands above 140g/km. In particular, the 101-120g/km band experienced a market share gain of 8.9%, from 16.7% to 25.6%.

Shifting consumer behaviour has also been guided by the popularity of small, low-CO2 emitting cars in national scrappage schemes, which heavily influenced European new car sales in 2009.

"The marked reduction in average CO2 emissions is a consequence of changing buying habits and in particular, the downsizing to smaller, more economical cars, driven by scrappage incentives and recessionary uncertainties," said David Di Girolamo, head of JATO Consult.

"This is accelerating the decreases made through the introduction of new, ever-more efficient models and technologies. The achievement here should not be under-estimated: car makers are offering models that are safer and more feature-rich, whilst still improving their environmental credentials."