Planting Trees and Managing Soils to Sequester Carbon
As noted by Brown, as of 2007, the shrinking forests in the tropical regions were releasing 2.2 billion tons of carbon per year. Meanwhile, expanding forests in the temperate regions were absorbing 0.7 billion tons of carbon annually. On balance, a net of some 1.5 billion tons of carbon were being released into the atmosphere each year, contributing to global warming.
The tropical deforestation in Asia is driven primarily by the fast-growing demand for timber. In Latin America, by contrast, it is the growing demand for soybeans and beef that is deforesting the Amazon. In Africa, it is mostly the gathering of fuel wood and the clearing of new land for agriculture as existing cropland is degraded and abandoned. Two countries, Indonesia and Brazil, account for more than half of all deforestation.
Included in the Plan B blueprint to stabilize climate are plans to end net deforestation worldwide and to sequester carbon through a variety of tree planting initiatives and the adoption of improved agricultural land management practices. Today, because the earth’s forests are shrinking, they are a major source of CO2. The goal is to expand the earth’s tree cover, growing more trees to soak up CO2.
Other countries cutting down large areas of trees will also face the environmental effects of deforestation, including flooding. If Brazil’s Amazon rainforest continues to shrink, it may also continue to dry out, becoming vulnerable to fire. If the Amazon rainforest disappears, it would be replaced largely by desert and scrub forestland. The capacity of the rainforest to cycle water to the interior, including to the agricultural areas to the south, would be lost. At this point, a fast-unfolding local environmental calamity would become an economic disaster, and because the burning Amazon would release billions of tons of carbon into the atmosphere, it would accelerate global warming.
Protecting the earth’s forests means halting population growth as soon as possible, and, for the earth’s affluent residents who are responsible for the growing demand for beef and soybeans that is deforesting the Amazon basin, it means moving down the food chain. A successful deforestation ban may require a ban on the construction of additional biodiesel refineries and ethanol distilleries.
Against this backdrop of growing concern about the forest-climate relationship, a leading Swedish energy firm, Vattenfall, has examined the large-scale potential for foresting wasteland to sequester carbon dioxide. They begin by noting that there are 1.86 billion hectares of degraded land in the world-land that was once forestland, cropland, or grassland-and that half of this, or 930 million hectares, has a decent chance of being profitably reclaimed. Some 840 million hectares of this total are in the tropical regions, where reclamation would mean much higher rates of carbon sequestration.
Vattenfall estimates that the maximum technical potential of these 930 million hectares is to absorb roughly 21.6 billion tons of CO2 per year. If, as part of a global climate stabilization strategy, carbon sequestration were valued at $210 per ton of carbon, the company believes that 18 percent of this technical potential could be realized. If so, this would mean planting 171 million hectares of land to trees. This area-larger than that planted to grain in India-would sequester 3.5 billion tons of CO2 per year, or over 950 million tons of carbon.
Adapted from Chapter 8, “Restoring the Earth ,” in Lester R. Brown, Plan B 3.0: Mobilizing to Save Civilization (New York: W.W. Norton & Company, 2008). This excerpt and the entire book is available for free downloading and or purchase at www.earthpolicy.org/Books/PB3/index.htm.
Source: Earth Policy Institute