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The automotive implications on global energy consumption and climate balance

Gregory Launay, translation by Audrey Brousseau - Last update: August 25th, 2012


Implications on global energy consumption

Transport consumes about 2.1 gigatons of oil equivalent (Gtoe) of final oil (or refined oil, opposed to crude oil) a year. It represents a little over 60% of the total oil consumed in the world. This percentage has been soaring over the last 30 years; in 1973 the implications of transport on oil consumption was only 45%.

Final oil consumption by business sector, in millions of toe - Source: International Energy Agency, 2009

The rise of the transport sector illustrates its dependence on oil (the automobile is 98% dependent). Industrial sectors tried to replace oil by alternative primary resources after the 1970s oil crisis…and transport has not managed to do so. The energy density constraint is blatant here, and in this addiction to oil, transport tops number one.

Oil represents about 42% of the final energy that is consumed (3.5 Gtoe out of a total of 8.2 in 2007); transport thus represents a large quarter of our global energy consumption (2.1 Gtoe out of 8.2).


What about the automobile?

In France, the distribution of transport modes reveals that the automobile represents over 50% (25 million tons out of nearly 50) of oil consumption.

Consumption of oil products by final usage in France, in millions of tons - Source: Energy Observatory, 2002

When applied to global transport consumption, this ratio is 1.05 Gtoe of oil for the automobile. International transport is not taken into account to produce those national statistics. Transport by air, by train or by ship is thus minimized here.

Another calculation method would be to start from the estimation of the global fleet. 1 billion vehicles consuming 9 liters per 100 kms and covering 15000 kms a year give 1.16 Gtoe of oil, or 60% of the 2.1 Gtoe of oil consumed in the transport sector. To draw a more vivid comparison, it corresponds to 30 million oil barrels a day (out of the 85 million that are consumed). This is an order of magnitude: transport counts for 1.2 Gtoe of oil a year, which amounts to:

  • 15% of the final global energy consumption
  • 34% of the final global oil consumption

Let’s focus now on greenhouse effect gases…

Implications on the climate balance

So as not to get confused, some preliminary remarks have to be made. There are three ways to categorize greenhouse effect gases, and it’s essential to distinguish them:

The first one consists in counting all greenhouse effect gases that are directly derived from human activities, as the United Nations define them. Here are those gases:

  • carbon dioxide (CO2)
  • methane (CH4)
  • nitrous oxide (NH4)
  • several fluorinated synthetic gases (HFC, PFC et SF6)

In order to simplify counting those gases, each one is given a Global Warming Potential. They can be added together and counted as « CO2 equivalent ». Another method consists in focusing on carbon dioxide alone, as it is by far the heaviest gas and the one which is directly linked to the combustion of fossil resources. Finally, among CO2 emissions, only those which are directly linked to the combustion of fossil resources are sometimes taken into account.

Here are the results of those three methods:

Global emissions of greenhouse effect gases- Source: MEDAD, 2009 – 2006 figures

When qualifying the implications of each sector, it is thus important to know what sum is referred to!

As far as transport is concerned, 2004 figures show a little over 6 gigatons of CO2 equivalent (or 6 Gt CO2eq), or a little over 12% of total greenhouse effect gases emissions. Nearly all emissions coming from transport are CO2 emissions.

Global emissions of greenhouse effect gases by sector - Source: GIEC, 2007 – 2004 figures

This figure is of course very high but probably not as much as the implication of the automobile in this sector may bring about. For example, it may be observed that LULUCF (Land use, Land-use Change and Forestry, in other words deforestation) has more implications than transport! Who knows this? Another remark: the increase of greenhouse effect gases emissions from the automobile is not the highest between 1990 and 2004. LULUCF and Energy come before.

A zoom in on industrialized countries (let’s say the OECD) might moderate these comments. In those countries where forests are generally well managed and energy increase is strictly monitored, transport is actually the main cause of increasing fossil CO2 emissions.

Implications of transport on fossil CO2 emissions in EU (in millions of tons) - Source: Transport & Environment, 2009


Zoom in on the implication of the automobile

In France, a little over 60% of CO2 emissions from transport are ascribed to the automobile (car passengers and commercial vehicles).

CO2 emissions by transport mode in metropolitan France (134 Mt in 2006) - Sources : CITEPA, 2006

Another ratio calculated on a global scale shows that about 3.6 Gt of CO2 equivalent are ascribed to the automobile. This figure is probably overestimated because it does not take international transport into account.

The calculation produced from the estimation of the global vehicle fleet (one billion vehicles emitting 225 grams of CO2 per km covering 15000 kms a year) gives about 3.4 Gt of CO2.

In the study they published in May 2009, McKinsey & Co produce 3 Gt for passenger cars only (without light commercial vehicles). In short, the order of magnitude is correct. Automotive transport annually weighs about 3.4 Gtoe CO2eq, which corresponds to:

  • 12% of fossil CO2 emissions (about 28 Gt CO2eq)
  • 7% of greenhouse effect gases emissions (about 50 Gt CO2 eq)


Some comments…

Here are some personal remarks on those figures. First, it can be observed that the implication of the automobile on energy consumption is higher than on climate balance. That’s fairly normal since land managing is also taken into account in climate balance (deforestation, nitrous oxide emissions from agriculture…), which automatically decreases the implication of fossil resources consuming sectors!

What’s more, we have to keep in mind that the two main constraints (energy and climate) have to be considered differently.

The greenhouse effect gases constraint, which is linked to global warming, is illustrated through a political angle. The effects of global warming will only have a gradual impact on a long-term period. Only the population’s awareness entices car makers to respect regulations on CO2 emissions through their political views (see for example the bonus/malus system in France). The physical constraint, which is real, remains a remote preoccupation. In the near future, this is a “flexible” constraint.

On the contrary, the energy availability constraint shows a much more direct and visible implication. If oil supplies cannot meet the demand, cars stop being driven and there is nothing that regulations can do about it. In the near future, this is a “hard” constraint!

So, isn’t it surprising that regulations (which determine manufacturers’ developing) only take the climate constraint (CO2 emissions) into consideration and not the energy constraint?

While the climate issue is getting well accepted by the population, we may not sustain the collective belief that oil is getting scarce…