## Monday, October 13, 2008

### NPP Appropriation by Region

Which regions of the world appropriate (use) the most amount of Net Primary Productivity (NPP) per person?

Key
Region - Countries in each region can be found here. Populations based on CIA factbook data for 2008.
Human Use Per Person - Kilograms of carbon of NPP appropriated for human use per person.
Potential NPP - Grams of carbon per square meter per year of NPP that would prevail in the absence of human intervention.
Lost Potential NPP % - Percentage of potential NPP lost due to human induced land changes.
Human Use % - Percentage of actual NPP (removing lost potential) appropriated by humans.

Thoughts

The average human appropriates 1,240 kg of carbon of NPP a year. This is used to provide food, clothing, fuel and housing. I am not quite sure how to turn kg of carbon into an amount of food, cotton or wood. I saw one estimate that put 1/2 a kg of corn per kg of carbon. That would mean 1,240 kg of carbon would be the equivalent of 620 kg (1,364 lb) of corn.

Oceania (Australia and New Zealand) has the highest NPP usage rate per person of any region (8,340) by far (over 6.7 times the world average) even though human appropriation of NPP is only 6% for the region. Southern Asia has one of the lowest consumption rates per person, and yet because of the density of people living there, its human appropriation percentage is 56%.

North America (US and Canada) has a consumption rate (3,403) that is more than double that of Western Europe (1,694). Even so, the North American appropriation percentage (16%) is less than 1/2 that of the Western European percentage (34%) due to the lower population density of North America. This raises an interesting question of whether Europeans or Americans tax the environment at a greater rate. Looks like it depends on how you define it.

The amount of lost potential (10%) is almost as large as the amount of human use (14%, well really 13% if you use Potential NPP rather than Actual NPP for the denominator). This implies humans could almost double their consumption of NPP without additional strains on wilderness if they managed land better. How efficiently we manage the land is just as important as how much we take from it.

Southeastern Asia has a potential loss due to land changes that is actually higher than human consumption. Eastern Europe has the highest rate of lost potential at 27%. North America and Oceania are low in the amount of lost potential even though they have the highest rates of consumption per capita. Eastern Asia and Western Europe have low levels of lost potential even though they have high population densities.

Southeastern Asia has the most productive land with a NPP potential of 1022 gC/m2/yr more than double the average of 502 and over 10 times as high as North Africa.

Cavaets

This analysis does not take into account exports from one region to another. The US is a net grain exporter, so the actual NPP usage per American might be lower than stated. Forest fires and NPP usage from oceans are excluded from the analysis.

Source

Quantifying and mapping the human appropriation of net primary production in earth’s terrestrial ecosystems Table 3.