Nowhere on earth is the threat of biological impoverishment because of deforestation greater than in the Amazon Basin of South America. The Amazon supports approximately 300 million hectares of tropical forest, the largest single area of tropical forest communities in the world (Fig. 2). Estimates of global biodiversity point to the tropics as the source of 50 to 90% of all species on Earth (Wilson 1992); the richest forests often support over 300 tree species per hectare, approximately the same number of tree species in all of North America.

Recent estimates of deforestation suggest that between 1 to 3 million hectares are being cleared annually in the Amazon Basin (Lawrence 1997; Fig. 3). Based on estimates of 1% annual tropical forest loss, the Amazon may be losing as many as 11 to 16 species per day (Wilson 1989), and the resulting ecosystems are often highly degraded (Buschbacher 1986).

The deforestation of Amazonia presents a challenging study of the interactions among people, their values, and the environment.

 Is deforestation in the Amazon any different than what occurred in industrialized Europe and North America centuries past?

 Should Amazonians develop their lands as they see fit?

 Do peasant farmers actively clearing forests value their environment any differently than world conservation organizations, you, or I?

 What does the world stand to lose by watching the destruction of tropical forests?

These are some of the most hotly debated environmental questions today, leading to several international conventions like the recent United Nations Convention on Biodiversity at the Rio de Janeiro "Earth Summit" in 1992.

Factors leading to rapid tropical deforestation

Why are tropical forests being cleared in the Amazon Basin at such an alarming rate? Historically, deforestation has been caused by the interaction of many factors, seven of which are presented here for simplicity:

2. the need for peasant farmers to earn a livelihood

3. Brazilian government policies to construct highways, subsidize agriculture, and relocate farmers into the forests

4. the cattle industry's forced manipulation of peasant farmer land rights, and the marginalization of these farmers to the frontier

6. rapid degradation of pastures due to poor soil quality and the costs of reclamation

7. oversupplies of beef and timber leading to price deflation and debt with banks in industrialized nations. Large debt, in turn, exacerbates timber exports.

A growing number of ecologists and economists realize that economic valuation of tropical goods leaves out or "externalizes" too many costs, such as pollution that damages the environment, while failing to "capture" the whole value of environmental goods and services (Costanza et al. 1997a, Dailey et al. 1997). Ecological economists argue that economic decisions need to incorporate, in addition to the market value of tropical forests, the non-market values that people have for the environment.

 Non-consumptive use values: uses that are not "extracted" from the environment, such as birdwatching, sunbathing, paying for a documentary or TV show about the environment, photography, tree climbing, among others.

 Existence values: non-consumption "appreciation" or moral values, including the intrinsic value of species existence, stewardship, and the value of preserving the environment for future generations. This last category has received considerable attention, and the human welfare benefits provided by the environment are called ecosystem services. There are many functions that ecosystems perform that, if permanently damaged, would cost humans to replace. Table 1 presents global ecosystem services recently identified by a group of ecological economists.

Table 1. Ecosystem services and examples (modified from Costanza et al. 1997b).

Ecosystem service Ecosystem functions Examples

Gas regulation Regulation of atmospheric chemical composition CO2/O2 balance, O3 for UV protection

Climate regulation Regulation of global temperature, precipitation Greenhouse gas regulation

Disturbance regulation Damping of ecosystem response to environmental fluctuation Storm protection, flood control, drought recovery

Water regulation Regulation of hydrological flows Providing water for agricultural industrial, and human uses

Water supply Storage and retention of water Provisioning

Deforestation of Amazon in An Alarming Rate. (1969, December 31). In DirectEssays.com. Retrieved 18:59, May 21, 2013, from http://www.directessays.com/viewpaper/67175.html

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