Imagine a world of deep green shadows, where shafts of light illuminate the verdant home of literally thousands of living creations, from rare tropical flowers and exotic insects to enormous predators like jaguars and tigers. Now imagine that world gone forever, lost to deforestation.
According to recent estimates from the United Nations Food and Agriculture Organization, the rate of global deforestation has slowed somewhat over the past 10 years. Nonetheless, we're still losing an estimated 13 million hectares, or 32 million acres -- roughly the size of Costa Rica -- each year to deforestation.
Most of the deforestation that has occurred since 1990 has occurred in tropical countries. Brazil, home to the immense Amazon Basin, has clear cut more forests than any other country, losing more than 42 million hectares (over 103,784,000 acres) to deforestation between 1990 and 2005. That's an area roughly equal to the size of California.
Other countries with severe deforestation problems include Indonesia, Sudan, Myanmar, Congo, Zambia, Tanzania and Nigeria, according to NASA's Earth Observatory. As you can see, many of these are developing countries that are struggling to compete in an international marketplace. Clearly, economics is behind much of the deforestation seen worldwide.
Causes of Deforestation
Like most complex environmental problems, deforestation doesn't have a single cause. Deforestation also occurs for different reasons in different regions. The loss of North American hardwood forests in the 1800s isn't an exact parallel to the current loss of tropical rainforests in Africa.
Today, the biggest cause of deforestation is converting forests to cropland and pasture for grazing animals. Much of this isn't for agribusiness or factory farming; rather, it's for small-scale subsistence farming, particularly in developing countries.
In many cases, the trees aren't logged for timber, but are burned in a style of agriculture known as "slash-and-burn" farming, in which the burned underbrush and trees form a nutrient-rich ash layer over soils that can be poor in nutrients (soil in tropical rainforests are typically poor-low-nutrient soils, so slash-and-burn agriculture is especially common in the tropics.
In addition to subsistence farming, large-scale agribusiness has in recent years opened up large swaths of virgin forests to deforestation; in the Amazon, this is often done for cattle ranching, while in parts of Asia, palm tree plantations are replacing much of the forests. And even in humid, rainy tropical areas, forests on the fringes of human settlement are prone to deforestation by forest fires.
Commercial logging -- legal or illegal -- is another important cause of deforestation. Many of the roads that are built to provide access to logging areas eventually become roadways for other commercial activities. And once clear cutting, in which all the trees are removed from an area, has denuded a landscape, most are turned over to agriculture instead of being restored to forests.
The Effects of Deforestation
No habitat on Earth can compare to forests in terms of diversity of life. About 70 percent of the planet's land animals and plants live in forests, and deforestation, by destroying their home, is effectively wiping out these plants and animals -- many of which haven't even been discovered yet. In just the past 35 years, we have lost almost one-third of the Earth's biodiversity due to deforestation, according to the World Wildlife Fund.
Forests also play a critical role in preserving water, in terms of quality and quantity. The canopy of trees over the forest floor slows the rate at which rainfall penetrates the forest and hits the ground. As a result, more water stays in the forests, in the canopy and on the ground. By contrast, rainfall in areas where clearcutting has eliminated all plant cover, immense amounts of runoff cause severe flooding downstream.
Water quality is also affected by deforestation: Exposed soils in clearcut forests wash downstream with rainfall, resulting in muddy, undrinkable water and stark, eroded landscapes with little or no arable soil.
Perhaps the most alarming effect of deforestation is its powerful impact on global warming and climate change. Forests -- especially tropical rainforests -- contain titanic stores of carbon in the form of plant biomass. (Tropical forests alone contain 210 gigatonnes of carbon.) When those tons and tons of plant biomass are burned or cut down and left to decompose, the carbon is released into the atmosphere as carbon dioxide, or CO2.
Because CO2 is such a powerful greenhouse gas, the rapid pace of deforestation is directly linked to the current rise in the greenhouse effect. The greenhouse effect warms the planet, and when it becomes more pronounced, the result is the rise in worldwide temperatures known as global warming.
Climate disruptions, however, go even further than global warming. The evaporation of water from tropical rainforests helps to cool vast regions of the Earth; when those forests are gone, the result is a hotter and more arid climate. According to NASA Earth Observatory, "replacing tropical forests with a landscape of pasture and crops creates a drier, hotter climate in the tropics. Some models also predict that tropical deforestation will disrupt rainfall pattern far outside the tropics, including China, northern Mexico, and the south-central United States."
Sustaining Forests for the Future
From local environmental activists like Chico Mendes and Wangari Maathai to the halls of international organizations like the United Nations, the Sierra Club and the Rainforest Action Network, activists are sounding the alarm about the imminent perils of deforestation.
Shade farming, which doesn't require clear cutting of forests, is one option to reduce deforestation. Other activists are calling for more sustainable harvesting of forest products like rubber, cork, fruits and medicinal plants. Parkland and other protected areas that encourage ecotourism provide employment and economic incentives to halt the destruction of forests.
One popular idea is the idea of "zero net deforestation," which allows some clearcutting and other deforestation, provided the net quantity, quality and carbon density of forests is maintained. Properly managed, this would preserve the biodiversity of forests and reduce greenhouse gas emissions.
But the global magnitude of deforestation demands a global response, and thus far that has been lacking. Without meaningful action very soon, our priceless and irreplaceable forests may soon be gone ... forever.