CliSAP successfully finished in 2018. Climate research continues in the Cluster of Excellence "CLICCS".

The World’s Fleet of Cars is Growing – And CO2 emissions with it


Passenger car travel is a significant contributor to the total emissions of greenhouse gases and thus, to climate change. Worldwide, emissions from cars increased by almost 45 percent between 1990 and 2007 alone. Concepts for a sustainable means of mobility are therefore needed.

In order to determine the amount of future CO2 emissions from passenger cars, scientists from Vienna have been developing long-term scenarios with Prof. Jürgen Scheffran from the KlimaCampus. Such estimates should help to determine how emissions can be reduced in the future – for example through technological innovations in gas and renewable energies.

The researchers modeled the number of car-owners across eleven regions globally, through the year 2050. They then used three different approaches and compared each of them. In their study, the scientists assume that purchasing patterns will, in principle, develop along the same lines across all countries, with the demand for cars largely being determined by per-capita income. Globally, Gross Domestic Product is expected to increase five times over through 2050, and it is expected that this will be clearly reflected in the rate of car ownership: depending on the model one chooses, the number of cars worldwide should increase to a total of between 1.7 and 2.7 million cars. North America is likely to maintain its leadership in this area, followed by the West European countries and the Asian Pacific members of the OECD. For worldwide greenhouse gas emissions, this means an increase from 3.3 billion tons per year today, to a level of between 5.1 and 8.2 billion tons of CO2 in 2050.

Why the variance in prognoses between the three models? Income is the deciding factor in all calculations of the number of cars globally. However, different aspects are also considered – for example, the density of demand once a level of one car per person is reached. Yet there is one trend that is clear in all models: demand for cars will increase in the coming decades, above all in the newly industrialized and developing countries.

I. Meyer, S. Kaniovski, J. Scheffran (2011) Scenarios for regional passenger car fleets and their CO2 emissions, Energy Policy (online first) (doi:10.1016/j.enpol.2011.01.043).