Deforestation



Deforestation

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What is Deforestation?

Deforestation is the permanent destruction of indigenous (native) forests. It is the loss of forest cover to be replaced by other land uses. It is a major global problem and has serious consequences.

How bad is it?

Forests once covered 6 billion hectares of the Earth but now only 4 billion hectares are left. Trees are important to our survival because, like other green plants, they produce oxygen. Without oxygen, animals, including humans, cannot survive!

Approximately 200,000 square km of forests are depleted each year. By now, approximately half of forests once occupied the earth’s surface has been deforested.

Deforestation has resulted in the reduction of indigenous (native) forests to four-fifths of their pre-agricultural area. Indigenous forests now cover 21% of the earth's land surface.

What causes deforestation?

Deforestation occurs for several reasons which include:

• Timber harvesting (commercial logging)

• Clearance for agricultural purposes

• Clearance for settlement

• Other reasons that may contribute to deforestation include the construction of towns or the building of dams which flood large areas.

Overpopulation

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In 8000 B.C., only 5 million people were alive—roughly the population of today’s Papua New Guinea. Overuse of the world’s natural resources was hardly an issue. Now some 6 billion mouths must be fed and bodies clothed and housed. Misuse or depletion of the Earth’s treasures to meet those needs, for example unsustainable logging, poor farming practices, and overfishing, threatens human life and health around the world.

According to the United Nations, population increases have slowed or even stopped in Europe, North America, and Japan. Nevertheless, global population continues to rise at a rate of roughly 78 million people per year. Most of the growth is taking place in sub-Saharan Africa and parts of South and Western Asia—areas least able to afford more people. Not coincidentally, the same places are plagued by deforestation and other unsustainable exploitation of natural resources.

The challenge remains to find ever more efficient and less environmentally harmful ways to feed the world. Better management of soil—for example, by rotating crops—can reduce the need to clear more woodland for agriculture. Contour plowing diminishes water-polluting runoff. Some governments have limited or banned the use of DDT as an insecticide because of its cumulative effects in the food chain.

As the Earth’s population continues to mushroom, can ways be found to manage natural resources without causing ecological collapse? The most successful efforts are almost always the result of cooperation between government and industry. But as is true with all government regulation, laws tend to be effective only when they are understood and supported by the people who are affected: both producers and consumers.

Surface Mining

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Surface mining (also commonly called strip mining, though this is actually only one possible form of surface mining), is a type of mining in which soil and rock overlying the mineral deposit (the overburden) are removed. It is the opposite of underground mining, in which the overlying rock is left in place, and the mineral removed through shafts or tunnels.

Surface mining is used when deposits of commercially useful minerals or rock are found near the surface; that is, where the overburden is relatively thin or the material of interest is structurally unsuitable for tunneling (as would usually be the case for sand, cinder, and gravel). Where minerals occur deep below the surface—where the overburden is thick or the mineral occurs as veins in hard rock— underground mining methods are used to extract the valued material. Surface mines are typically enlarged until either the mineral deposit is exhausted, or the cost of removing larger volumes of overburden makes further mining no longer economically viable.

In most forms of surface mining, heavy equipment, such as earthmovers, first remove the overburden. Next, huge machines, such as dragline excavators or Bucket wheel excavators, extract the mineral.

Urban Sprawl

Perhaps you've noticed your community is getting a little bigger. Road construction seems to be everywhere and traffic is more heavy than it used to be; new strip malls and "big box" stores are popping up; and land on the outskirts of your town is being cleared for new housing subdivisions. Your community could be experiencing urban sprawl, an issue that has affected cities and towns across the country as well as the Great Lakes region.

Urban sprawl can be generally defined as wide-spread, low-density development that consists primarily of strip commercial developments, such as malls and large office buildings, and housing subdivisions connected by new, wide roads and boulevards. The subdivisions are set apart from other development and built within a specific price range, and people are dependant on their cars to get them from one place to another. With sprawl, fewer people occupy more land and as the people spread out, so do the buildings, roads and houses. Urban sprawl is difficult to define but people usually know it when they see it. The following maps describe what an urban sprawl suburb might look like (left) compared to the land use plan of a town that avoids sprawl (right).

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Maps by Gail Dennis, Michigan Land Use Institute

Source: "The Next American Metropolis," by Peter Calthorpe.

The Great Lakes region is losing its rich farmland and other green fields to urban sprawl at an alarming rate, and the environment and the residents are paying the price. Many cities of the Great Lakes region, such as Chicago, Detroit, Cleveland, are seeing their businesses and residents move to the suburbs, forever destroying open spaces and leaving behind cities of abandoned buildings with fewer tax payers.

Sprawl can damage ecological systems and their natural functions, such as wildlife habitats and wetlands. Housing subdivisions, commercial developments, and the roads that connect them all divide a landscape, which results in habitat fragmentation. This fragmentation forces wildlife to either find another place to live or compete with each for a smaller amount of land. Urban sprawl is also threatening wetlands, an important key to healthy ecosystems. In addition to being home to a number of critical wildlife and plant species, wetlands improve water quality by filtering out sediments and other pollutants, protect the shorelines of rivers and lakes from erosion, and help control and reduce flooding. However, since 1800, over two-thirds of Great Lakes wetlands have been lost or severely damaged, and land development continues to destroy wetlands today.

Farming

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What is agriculture?

Agriculture, or farming, is the simplification of nature's food webs and the rechanneling of energy for human planting and animal consumption.  Huh?  You may ask.  To simplify, agriculture involves redirecting nature's natural flow of the food web.  The natural flow of the food web is-the sun provides light to plants.  Plants convert sunlight into sugars which provide food for the plants (this process is called photosynthesis). 

Plants provide food for herbivores (plant-eating animals, i.e., sloths) and the herbivores provide food for carnivores (meat-eating animals, i.e., jaguars).  Decomposers or bacteria, break down plants or animals that have died.  Nutrients from the plants and animals go back into the soil and the whole process starts anew. 

What happens with agriculture is that this web is interrupted.  Instead of having herbivores eat the plants, the plants are protected for human consumption.  This means that not only are plant eating animals excluded from the food web, but also carnivorous animals and even decomposers.  However, if a farmer is planting corn to feed their cattle, the cattle eat the corn to fatten up and then are eventually slaughtered for human consumption.  Even though a herbivore (cow) is eating the plant (corn) the web in interrupted when the cow is killed for human consumption. 

Dams

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Another flood strategy is construction of dams, such as those of the Tennessee Valley Authority. They have been used to store water during times of heavy buildup and for gradual release during dry periods. China’s Xiaolangdi Multipurpose Dam Project is expected to mitigate the flooding of the Yellow River, which has been called “China’s Sorrow.”

Dams offer other advantages. They are most commonly used to generate electricity through water power, to charge water-supply systems, and to create artificial lakes for recreation. However, dams can harm the environment. They interfere with fish migration and habitat for other wildlife by reducing water flow.

Downstream human communities also may suffer from diminished water resources. Worldwide, more than 200 rivers flow through two or more countries. Friction over water resources constantly threatens conflict in the Middle East. No country is so dependent on a single lifeline as Egypt is on the Nile—whose source is in Ethiopia. Eighty percent of Iraq’s water originates outside its borders. Headwaters of the Tigris and Euphrates, which flow through Syria and Iraq, are largely controlled by Turkey. The two downstream countries have complained about massive Turkish dam-building programs.

In seeking to control flooding by manipulating water flow, people create new sets of problems.

Landfills

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A landfill, also known as a dump, rubbish dump or both, Rubbish Landfill Dump (and historically as a midden), is a site for the disposal of waste materials by burial and is the oldest form of waste treatment. Historically, landfills have been the most common methods of organized waste disposal and remain so in many places around the world.

Landfills may include internal waste disposal sites (where a producer of waste carries out their own waste disposal at the place of production) as well as sites used by many producers. Many landfills are also used for other waste management purposes, such as the temporary storage, consolidation and transfer, or processing of waste material (sorting, treatment, or recycling).

A landfill also may refer to ground that has been filled in with soil and rocks instead of waste materials, so that it can be used for a specific purpose, such as for building houses. Unless they are stabilized, these areas may experience severe shaking or liquefaction of the ground in a large earthquake.

Large number of adverse impacts may occur from landfill operations. These impacts can vary: fatal accidents; infrastructure damage (e.g., damage to access roads by heavy vehicles); pollution of the local environment, off gassing of methane generated by decaying organic wastes (methane is a greenhouse gas many times more potent than carbon dioxide, and can itself be a danger to inhabitants of an area); harboring of disease vectors such as rats and flies, particularly from improperly operated landfills, which are common in developing countries; injuries to wildlife; and simple nuisance problems (e.g., dust, odor, vermin, or noise pollution).

Desertification

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Parts of it look like the surface of Mars. Beginning in 1968, the Sahel—a vast, ancient savanna that borders the lush, tropical regions of West Africa—fell victim to a catastrophic five-year drought. Abnormally dry conditions sped up the invasion of a neighbor to the north: the Sahara, the world’s largest desert. When the grass- and scrubland of the Sahel lost its already limited ability to support crops and livestock, famine came to visit along with the sand.

Verdant land can become desert as a result of drought, increased erosion due to land-clearing, poor farming techniques, overgrazing of livestock, and drainage of surface and underground water for crop irrigation and household and industrial use.

Even an existing desert can become more of a wasteland when ecological balances change. The Sonora and Chihuahua Deserts of the U.S. Southwest and Mexico have become increasingly barren as native plants and wildlife have been diminished by several factors, including the depletion of groundwater by human activity.

Perhaps the most frightening aspect of desertification is that it tends to be what scientists call a runaway phenomenon. Once it begins in a particular area, it is almost impossible to stop, and it cannot be reversed within a human lifetime.

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