Globally, the average carbon footprint is four tons of carbon dioxide equivalent per person per year. However, this data is a bit misleading, because the size of someone's carbon footprint varies considerably, depending on where he or she lives. People in industrialized nations such as Canada produce much larger carbon footprints than people in the developing world in places like Malawi. Breakdowns of average carbon footprint per country tend to be more revealing than looking at the global average.
The information in this article comes from the first decade of the 21st century. Most nations were showing an upward trend in carbon emissions at this time, despite attempts to curb carbon emissions in the interests of protecting the environment. It is important to note that very few nations had shrinking average carbon footprints, and that growth rates were quite variable, with some countries having rapidly expanding carbon footprints when compared to others.
Carbon footprints are based on the amount of greenhouse gases generated to support someone's lifestyle over the course of a year. They are measured in carbon dioxide equivalent, with all greenhouse gases being fitted along a rubric which uses carbon dioxide as a base. Some footprints look at primary and secondary sources, separating the two. For example, when someone drives a car, this generates a primary source of carbon dioxide. When someone drinks bottled water, this generates a secondary source; the emissions are not in the bottle itself, but in the manufacturing and transportation of the bottle.
North Americans have the highest average carbon footprint, around 20 tons per year. A study conducted by MIT students showed that members of the homeless population in the United States have a carbon footprint of around eight and a half tons annually. By contrast, in Ethiopia, the average carbon footprint is .01 tons per year. Some other examples include Russia, 10 tons per year, Egypt, at two and a half tons well below the global average, and France, slightly higher than the global average with six tons per year. Residents of China hover close to the global average with a carbon footprint of 3.8 tons per year.
Researchers have pointed out that the average carbon footprint is heavily influenced by the culture in which someone lives. In regions where consumption is ubiquitous and widespread, footprints are high, even though individuals may live below the average national footprint. Conversely, in nations where poverty is high and people lack purchasing power, the footprint stays low. Interestingly, some of the nations most vulnerable to changing climate conditions, which many people believe may be in part caused by carbon emissions, have some of the lowest carbon footprints.