The size of the bars to the left indicates the amount of GDP that is produced by each category. So, sectors of the economy that are "making bucks." The ecologists viewpoint is the classic food pyramid, at the bottom are all the things we need to support the rest: we depend on agriculture for our food, extraction of natural resources for our energy and raw materials, and forests for the wood to build all those houses. It is amazing to me that the connection is not made that if you have no more forests, you build no more conventional houses. We've all seen what a bursting bubble in the housing market has done to our economy. What if global warming so alters our climate that we don't have enough at the bottom of the pyramid to sustain our current standard of living? Does anyone else see the problem with the pyramid? Maybe a little unstable?