When major events come to the fairgrounds, people who live nearby can make extra money by charging visitors to park cars on their front lawns. In much the same way, people who have a place to capture carbon on earth can profit by supplying carbon parking.

Carbon, element 6 on the periodic table, is a building block of all living things. Carbon is released into the atmosphere as carbon dioxide gas when animals breathe and when their wastes break down. Plants take up carbon when they grow and release it when they decay. But modern society has opened the spigot. Volumes of carbon flow into the atmosphere when fossil fuels are burned, when forests are harvested or when soils are intensively tilled.

Karl Kupers, a Washington farmer, is already selling carbon credits from his conservation-tillage wheat field. Kupers and a group of partners formed the Pacific Northwest Direct Seed Association and entered a 10-year contract with Louisiana-based Entergy Corp. Entergy gets credit for carbon-dioxide-emissions reductions achieved by the farmers to offset the carbon dioxide emissions from the company's power plants in the United States.