As governments move to address global warming, the contribution of agriculture, particularly livestock production, to greenhouse gas emissions is increasingly being identified as one of the primary culprits.

Dr Frank Mitloehner, a Professor and Air Quality Specialist with the Department of Animal Science at the University of California Davis, says many countries are inefficient and resource hungry when it comes to livestock production so the contribution of their livestock industries to global warming skews the numbers.

Dr Frank Mitloehner-University of California Davis

In the United States, to give you that example, the number one culprit of carbon emissions is the use of fossil fuel.

Energy production and use and transportation, these two sectors make up for more than 50 per cent.

The livestock sector in the United States contributes to 4.2 per cent of all greenhouse gasses.

But, in other countries of the world, that is not the case.

For example, in some South American countries, livestock contributes to half of their carbon footprint.

In some African countries livestock contributes to as much as 90 per cent so it's not fair to use one global average, which is then completely distorting the contribution livestock have in North America or in South America or in Africa.

If you compare different regions throughout the world, what by far has the greatest impact on their footprints, is the efficiency under which they can be produced.

Dr Mitloehner says, if you can increase efficiency you can decrease emissions.

As an example he points out the average milk cow in California produces 25 thousand pounds of milk per year, 20 times more than in India so, if you need 20 times more cows to produce the same amount of milk, the environmental impact is going to be 20 times greater.