Alleviating the “Greenhouse Effect,” trees act as carbon “sinks.” 
- 1 acre of new forest will sequester about 2.5 tons of carbon annually. Trees can absorb CO2 at the rate of 13 pounds/tree/year. Trees reach their most productive stage of carbon storage at about 10 years.
- In its “Reforesting the Earth” paper, the Worldwatch Institute estimated that our planet needs at least 321 million acres planted to trees just to restore and maintain the productivity of soil and water resources, meet industrial and fuel-wood needs in the third world, and annually remove from the atmosphere roughly 780 million tons of carbon as the trees grow. This 780 million tons represents the removal of about 25 percent of the 2.9 billion tons of carbon currently going into the earth’s atmosphere.
- Planting 100 million trees could reduce the amount of carbon by an estimated 18 million tons per year and at the same time, save American consumers $4 billion each year on utility bills.
- For every ton of new wood that grows, about 1.5 tons of CO2 are removed from the air and 1.07 tons of life-giving oxygen are produced. During a 50-year life span, one tree will generate $30,000 in oxygen, recycle $35,000 worth of water, and clean up $60,000 worth of air pollution or $125,000 total per tree without including any other values!
It’s more a matetr of cutting down over-consumption and waste in the G8 / developed nations and making sure India, China, Indonesia, Brazil et al don’t make the same mistakes we’ve made in their rush to have the same standard of living as we do. That means designing cities with public transport and efficiency in mind, not flattening farmland to build suburban tinkertoy boxes accessible only by carbon-spewing devices. The world can indeed hold a lot more people than it does now, but not if we all live like North Americans.