Rainforest Destruction:
Understanding the Cross Cutting Issues InvolvedClimate Change and Global Warming
“Although all consequences of deforestation are potentially serious, perhaps the most serious consequence is that of climate change due to the loss of trees. Earth has an atmosphere which contains a variety of gases, all in a delicate balance, to ensure life on Earth. One of these gases in Earth’s atmosphere is carbon dioxide; a gas which helps moderate heat loss to outer space. Insulating gases such as carbon dioxide are called “greenhouse gasses because their function is much like that of the glass in a greenhouse: they allow solar heat into the system, but discourage its escape” (GFF 3). Other greenhouse gases include methane, chlorofluorocarbons, nitrous oxide, and ozone. If there are additional greenhouse gases, there will be a gradual increase in temperature on Earth�s surface. This could lead to changes in weather patterns, sea levels, and other cycles in nature that directly affect life on Earth (GFF 3).
The process of greenhouse gas increase is quite simple. Carbon dioxide levels increase for a number of reasons; but one of the main factors contributing to the increase of carbon levels is decay of woody material. The only way to help moderate the levels of carbon dioxide in the atmosphere is through plant life. Alive plants and trees absorb the carbon dioxide from decaying plants and trees. With a decrease in trees and plant life (due to deforestation) it is much harder to moderate these levels. Ultimately, the amount of carbon will increase due to a lack of plant life present to keep the carbon dioxide levels in check. This whole process leads to an “albedo effect which reflects more heat and light back into the atmosphere than would be the case if the sun shone on green trees�” (Dudley 23). The bottom line is that the increase in the carbon level and other greenhouse gas levels into the atmosphere leads to an increase in temperature, and eventually a change in climate and weather.” http://www.umich.edu/~gs265/society/deforestation.htm
In the Amazon alone, scientists estimate that the trees contain more carbon than 10 years worth of human-produced greenhouse gases. When people clear the forests, usually with fire, carbon stored in the wood returns to the atmosphere, enhancing the greenhouse effect and global warming. Once the forest is cleared for crop or grazing land, the soils can become a large source of carbon emissions, depending on how farmers and ranchers manage the land. In places such as Indonesia, the soils of swampy lowland forests are rich in partially decayed organic matter, known as peat. During extended droughts, such as during El Niño events, the forests and the peat become flammable, especially if they have been degraded by logging or accidental fire. When they burn, they release huge volumes of carbon dioxide and other greenhouse gases. Most of these climate predictions of decreased rainfall are based on a uniform and virtually complete replacement of tropical forests with pasture and cropland.
Rainfall and Temperature Impacts
Deforestation often proceeds in a patchwork fashion—clearings that branch off roads in a fishbone pattern, for example, or deforested islands within a sea of forest. On these local scales, deforestation may actually increase rainfall by creating “heat islands” that enhance the rising and overturning of air (convection) that leads to clouds and rain. Clouds and rainfall becomes concentrated over clearings. Whether the localized enhancement of rainfall will persist as larger and larger areas of forest are cleared is not currently known. Answers may come from more sophisticated climate models that accurately represent the patchwork progression of partially deforested landscapes.
NASA and Rainforest Destruction
