According to the United Nations FAO (Food and Agriculture Organization), forests cover 10 percent of the Earth's surface, or one-third of its land mass.
Over the decade of the 1990s, 160 million hectares of forest were lost, equivalent to four times the area of the Japanese archipelago. Converted into figures a little easier to relate to, this means our planet's forests are disappearing at the incredibly fast rate of 20 tennis courts per second, five Central Parks an hour, and around 440 square kilometers, the size of the Japanese island of Tanegashima, every day.
Major reasons for clearing forests, apart for lumber (commercial logging), include for conversion to land for cultivation, for grazing, and for housing.
Undergoing the most rapid deforestation is the Amazon in Brazil, with 2.3 million hectares (2003) of forest lost every year.
In the Rondonia region of Brazil for example, to sustain a swelling population and meet growing demand for food exports to China and other countries, forests are being cleared by fire to increase the available farmland. NASA'a space shuttle keeps a regular photographic record of this process.
Brazil: deforestation in the Rondonia region (c) NASA
As you can see, in just 30 years, a vast area has been converted into farmland.
Some may say there is little call for alarm, because the Amazon's high rainfall will soon cause the land to revert to forest. In reality however, forests do not grow where it rains a lot: rain falls because there is forest. Trees siphon up water from the soil from their roots, from where it passes up the trunk and evaporates out through the leaves. This water vapor forms clouds that cause rain to fall. When the forest goes, no water vapor is generated, and rain will no longer fall. In other words, once the forest has gone, rainfall decreases, causing the soil to become dry and barren and potentially deteriorate into wasteland or desert. If the felling of the Amazon rainforest continues at the current rate, it is said that in 100 years all the trees will be gone. In 1988 the Brazilian government switched to a policy of protecting the forest, and thanks to various initiatives, by 2005 destruction of forest had been reduced. A complex tangle of local interests however means that a dramatic improvement is yet to be seen.
Of course, the clearing of forests is not only a serious issue in the Amazon. If you click on "Present day: frontier forest only" on the Earthrium globe, you will see that very little native forest remains untouched by human interference. The turnover of generations in a forest can take hundreds, even thousands of years. It seems though that humans invariably think in units of only a few years, and only have eyes for short-term profit. Is it really that difficult to modify people's thinking so they no longer believe complacently that as long as it works now, who cares about the future?
* Brazil and the Rondonia region can also be viewed on Google Maps.
→View Rondonia on Google Maps