Our dependence on plants shot up from 1995 to 2005, according to a new NASA study. Here's a map that shows which regions use more carbon than they produce (red) and which regions produce more than they use (green).
According to the new study from NASA, in 1995, humans required 20.3 percent of all the plant material produced by our planet (or the photosynthetic capacity of the land.) By 2005, that had gone up by about five percent, to 25.6 percent, both because the population rose and because each person uses more plant products.
Here's NASA's explanation of the map:
This map shows the comparison for 2005. The colors represent the ratio between the amount of carbon people require and the amount of carbon Earth produced. At the top of the scale (dark red), the population needs at least ten times more plants than are grown locally. At the lower end of the scale (dark green), the land produces more vegetation that the local population needs. Gray areas are places where people in the area use less than 10 percent of the vegetation growing there. In the center of the scale (pale yellow) people use most of the vegetation.
In general, the greatest use of plant products occurs in highly populated regions, like Asia and large cities, and places that can not produce enough to support the population's requirements for plants, such as the African Sahel. Because these places use everything they grow and still need vegetation from elsewhere, they are very vulnerable to changes in climate that would reduce production and disruption in transportation that would make it more difficult to bring food and other plant products from other places.
The map shows the pressure on local ecosystems, but not per capita use. For example, in the United States, each person uses 5.94 metric tons of carbon (vegetation) per year, while in South-central Asia, people use 1.23 metric tons per year. However, the United States produces more than it requires, so the ratio between usage and vegetation is low. South-central Asia, on the other hand, uses less per person, but it has a high population that collectively require more carbon than the land produces, and so must import products from other regions.
[via NASA's Earth Observatory]