Table of Contents
Chapter 6
- Forests of the World
- Grasslands
- Parks and Preserves
Chapter 6
Forests of the World
One of our greatest natural resources that we have on our planet are the forests. These forests provide several ecological functions, including regulating the climate, regulating water runoff, purifying our air, and supporting rainfall among other benefits. These forests also provide the raw materials for many industrial sources. Trees provide wood for endless building all over the world. In harvesting wood for profit, or to clear more agricultural space, care is often not being taken about the permanent damage being done to forests that are thousands of years old, and the many life forms that call the forests home.
Current estimates indicate that we have currently only about 50% of the forests remain. This could lead to unforeseen consequences since forests play such a vital role in worldwide environment. Forests are large sources of carbon, and the burning and destruction of these forests are releasing large amounts of carbon into the atmosphere, which can lead to increased global warming. The moisture that is cycled through forests also effects other regions of the earth. Rain in the Midwest United States often times originates over the Amazon forest. With heavy deforestation in the Amazon, this could lead to increased drought conditions thousands of miles away.
Controlling deforestation can be difficult because it is a large business venture. Wood transactions account for nearly $100 billion dollars of trade per year. The majority of the use is for creating paper for developed countries, and most of the rest is used as a fuel source. So deforestation can be labeled as harmful, but large scale changes are unlikely to occur until alternatives to creating paper or providing fuel are found. One way this could be done is through better management of harvesting lumber, but so far this is only done in about 25% of currently harvested forests.
Brazil and Indonesia are currently the world leaders in deforestation. It is estimated that Brazil loses 1 acre of forest every second. This of course has a huge effect on the earth's biodiversity, since about 50% of all animal, plant, and microbial species are believed to reside in rain forests such as the Amazon rain forest in Brazil. One of the literally brightest examples that we can see are the Monarch Butterflies that live in forests near Mexico City for 5 months of the year (http://www.mhhe.com/Enviro-Sci/CaseStudyLibrary/Topic-Based/CaseStudy_DisappearingButterfly.pdf). The type of specialized conditions the Monarch's need only make up about 2% of Mexico's current forest system. While Mexico has attempted to protect this rare forest areas, native people's depend on the harvesting of this wood to survive. This shows the dilemma facing any attempts to regulate deforestation.
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| Migrating Monarch's. |
Fortunately most countries now realize what a vital resource that forests are, and they need to be sustained for global benefit. While most deforestation occurs to either harvest valuable wood or clear valuable agricultural space, a large percentage is also carried out by native residents who need the land or wood to provide for their families. A new global program REDD (Reducing Emissions from Deforestation and Degradation) has recognized this issue, and is attempting to now pay local residents a yearly stipend in exchange for not deforesting. While it is too early to see if the results are positive, it is a positive step a global stance on the importance of preserving our forests.
It is not only rain forests in developing countries that are in danger. Even in developed countries like the United States and Canada face issues of deforestation, especially in "Old Growth" areas. While the trees in these areas are large since they can be thousands of years old, and provide much raw materials, these forests are also home to unique species that do not exist elsewhere in the world. This is cause for much controversy in the United States, and even Presidential decrees to protect forests from further road construction has been overturned, and then reinstated. This again shows that there are no easy solutions that will make everyone happy.
Another man-made danger to North American forests comes from forest fires. The Forest Service had a policy of controlling and putting out any forest fires that occurred on public land. While this was done with the intent of preserving the forests, it is now recognized that forest fires are a natural part of the biological cycle that forests undergo. The fires clean out old and sick vegetation, and provide fuel for new generations of growth. With the control of wildfires however, many forests are now overpopulated with weak trees instead of fewer strong healthy trees. Efforts to correct these short sighted mistakes will now cost billions of dollars in forest clean-up, and there are again many opposing views on how it should be done.
Grasslands
Another prominent biome that is in danger are the natural grassland areas of the planet. Currently grasslands which include prairies, savannas, and open woodlands occupy about 25% of the earth's surface. While these areas are attractive for being easily adapted to urban, agricultural, or residential areas, they are still home to many species of plant and animal life. It is estimated that these natural grasslands are actually disappearing 3 times faster than the rain forests.
About 33% of the degradation of grassland areas can be attributed to overgrazing. When these lands are overgrazed, there is not enough vegetation to trap rainwater. The water then escapes the areas, and there is not enough moisture left to nourish new generations of vegetation. This also leads to natural wells and springs being depleted. This degradation can also affect the climate, as the now barren land reflects more heat, which in turn drives away rain clouds, starting the cycle of turning a once natural grassland into a desert environment.
In the United States alone, only about 30% of grazing grassland is considered to be in fair condition, and 55% is considered to be in poor or very poor condition. These overgrazed grasslands have opened up regions to be taken over by inedible plants such as sage and mesquite, which further diminishes the amount of grassland left to be used. The call for public land to no longer be allowed to be used for grazing is of course opposed by ranchers who use the land for grazing. As they provide a large percentage of the beef supply in the country they feel that access to these lands is vital to continue to meet demand for food.
Some alternatives that are currently being practiced are rotational-grazing, and alternate meat providers. With rotational-grazing, animal herds are confined to smaller areas. This ensures a uniform grazing and fertilization of the land, as opposed to the animals roaming freely and eating only the choicest plants. This allows the grasslands to recover more evenly. Alternate meat sources are also gaining in popularity. As animals such as bison, elk, and wildebeest's graze on a wider variety of plants than domestic animals, they are able to sustain themselves on smaller parcels of land. They are also more naturally resistant to extreme weather and predatory animals. There also appears to be a larger financial gain to be had from the leaner meats than from traditional beef.
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| Cattle herds |
Parks and Preserves
While the idea of setting aside land to be undisturbed by development is not new, as evidenced by Ancient Greece having sacred forests, and Britain setting aside Royal parks, most societies are making greater efforts to create park areas. It is estimated that currently 14% of the world's land area has been designated as a Park or a Preserve. While this should be encouraging news, upon closer examination we find that there is a wide range of what is considered a Park or Preserve.
There are currently 5 designations for park areas, ranging from Ecological reserves with little to no human presence to public recreation areas that can have millions of visitors per year. Naturally the public recreation areas with large amounts of human traffic can have issues with actually preserving the environment. While nature preserves attempt to limit human intervention, this can greatly depend on the management and money available to ensure that the borders of the park are enforced. Many of these preserves are also in remote areas that receive little human traffic but also have little biodiversity due to their remote nature.
Another issue with popular parks or preserves is that they are being overrun either in the form of visitors or by ever expanding industrial needs. Some parks have opened up to deforestation or dam-building for energy. Other parks are overrun with visitors which has a large impact on the natural ecology of the region. In Yellowstone park for instance, the wildlife has long since lost their fear of man, and now depend on human garbage for a large part of their diets. The congestion in these parks also has negative effects, such as pollution from the large number of cars driving through the area. Again there are many proposals for how to protect these natural preserves, but very little actual action that is taking place due to political considerations.
There is also the consideration of marine preserves. While 14% of land areas have a park designation, only about 5% of marine areas have the same designation. This has lead to overfishing and destruction of coral regions that house many types of aquatic life. It is predicted that at current rates, within 50 years there will be no visible coral reefs left anywhere on the planet. While the marine areas that have been fortunate enough to be designated as protected have about 30% more biodiversity than unprotected areas, it is still felt that these areas are not large enough for long term protection of marine biomasses.
There is also an issue of how much land can be dedicated to parks and preserves. There are different opinions on whether large preserves or smaller scattered preserves are more viable. While smaller preserves spread biomes out, thus protecting against disease or natural disasters wiping out populations, some animals need large territory. In this case there is a growing case for creating wildlife corridors. While taking up less land than large preserves, these corridors can link smaller preserves, and give larger animals the territory needed to roam, while still spreading out the various preserves to protect against natural disasters wiping out limited species. There will still be a need for larger preserves though, as some species require the density and solitude that can only be provided by being deep within preserves, as opposed to being on the 'edge' where there is more exposure to various weather effects and outside species.
While preserving marine and land biomes is a worthy goal, as we have seen it is often easier said than done. Many factors come into play, political, cultural, and biological. While each group has its own advocates, there needs to be balance met between all groups in order to have the best sustained chance of making sure these parks and preserves last and serve their intended function.
Chapter 10- Water Resources
- Water Compartments
- Water Pollution
Chapter 10
Water Resources
One of the most important resources, perhaps the most important, to sustained life on earth is water. Water is used in one form or another by almost all life on earth. In humans water makes up nearly 60% of our bodies. Without water our bodies would be unable to break down and distribute vital nutrients to keep us alive. Without water we would be fortunate to survive for more than a few days. Despite the obvious need for water it is yet another natural resource that is in danger mostly due to human interference.
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| Chart of Water Distribution (Principles of Environmental Science, p. 242) |
All water as we know it is part of the hydrologic cycle. Water can start out in the ocean, evaporate, come down on land thousands of miles away as rain, pass thru living organisms and eventually makes its way back to the ocean through rivers and streams. Along the way it can be detoured by plants who absorb it and allow it to evaporate back into the atmosphere before it makes its return to the oceans. The hydrologic cycle has many influences on where the water ends up, as solar energy, rainforests, and mountain ranges help to dictate where the water ends up in rain format. Because of these influences water is not distributed evenly across the planet, which makes preserving water resources even more crucial.
Water Compartments
Distribution of water across the planet is broken down into Compartments. Water has a residence time that it will stay in any one compartment. For example a single water molecule may be in the ocean for thousands of years before it finally evaporates and makes its journey to another compartment. The ocean is the biggest water compartment on the planet, holding about 90% of all the water on earth.
Of all the water on earth, only about 2.4% of it is fresh water, which is what is needed by most land based forms of life to survive. Of this 2.4%, 90% of that fresh water is currently frozen in glaciers, ice caps, and snowfields. Runoff from these glaciers and snowfields is still able to provide large amounts of fresh water needs to billions of people. However these glaciers and snowfields are being reduced yearly, a large portion of which is attributed to global warming. If these glaciers were to disappear that could leave billions of people without freshwater supplies.
The largest compartment of fresh water is called groundwater. Groundwater is rain that has percolated through earth and soil to form saturated underground zones. Many times this water is funneled into aquifers, which can range from a few hundred feet to vast underground rivers. For instance there is evidence of an underground sister river to the Amazon, Rio Hamza. This river is thought to be about 4km underground, and follow roughly the same path as the Amazon (http://www.guardian.co.uk/environment/2011/aug/26/underground-river-amazon). The flow of these underground aquifers can vary greatly. The Rio Hamza is thought to only move about 1mm/hour. Often times these aquifers can be tapped and used to supply wells or may produce natural springs. Again we run into problems of humans overusing these precious freshwater supplies. Aquifers can take years to recharge, and pollution can seep into them, damaging the aquifer as a source of fresh water.
Rivers and lakes are another major water compartment. Rivers provide a relatively small amount of fresh water as they flow quickly, and depend on other sources to keep them full and flowing. Lakes contain large amounts of surface water, but not all of it is unpolluted, and most of the lake water is found in just a few of the giant lakes in the world. Unfortunately not all of this lake water is fresh. Lakes are still importance sources of fresh water. There are also wetlands, while they may not contain as much surface water, it is these zones that slow down water runoff, and allow the recharging of aquifers.
Water Pollution
The biggest threat to our freshwater supplies is pollution. Pollution refers to any adverse physical, biological, or chemical change in the quality of fresh water. Some of this pollution occurs naturally, but the vast majority of it is from man-made sources.
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| Drainpipe near ocean (knowledge.allianz.com accessed 3/7/12) |
There are two basic ways for fresh water to become polluted. These are referred to as point and non-point sources of pollution. Point pollution is where a known source of pollution interacts with a water supply, such as drain pipes or sewage runoffs. These points are easier to monitor because they are easily identified and don't move. Non-point pollution refers to any point where pollution interacts with water sources, but are not easy to identify because these non-point sources can occur anywhere. This includes water runoff from fields, golf courses, and industrial areas, often after rainstorms. While these points are harder to track, they generally occur at predictable times coinciding with storms or floods. Non-point pollution also occurs when airborne chemicals are transported, sometimes thousands of miles, before falling into water sources with rain.
There are various types of water pollution, and they are commonly broken down into categories. These categories include pathogens, biological oxygen demand, and plant nutrients and cultural eutrophication.
Pathogens are disease causing organisms that end up in water supplies. These diseases include typhoid, cholera, dysentery, polio, and hepatitis. The main cause of these pathogens is human and animal waste. When the waste leeches into fresh water supplies, it exposes all who drink it to these diseases. Currently up to 25 million deaths per year can be traced back to these waterborne pathogens. While these diseases are rare in developed countries with sanitation systems, in underdeveloped countries these diseases account for nearly 80% of all sickness. The amount of dangerous pathogens in water can be measures by tracking coliform bacteria, which is the same kind of bacteria that would be present in human and animal intestines.
Biochemical oxygen demand is a standard measure of water contamination. The more waste products present in water, such as sewage, the more oxygen will be depleted due to decomposers using large amounts of the oxygen to metabolize the waste. This oxygen depletion makes it difficult to impossible for most aquatic forms of live to survive. The more waste in the water, the greater the oxygen depletion will be. This can cause large pockets of BOD zones where little to no life will be found.
BOD chart.
Another source of contamination in water supplies comes from plant nutrients and cultural eutrophication. While eutrophic waters are normally a sign of a healthy system, there can be too much of a good thing. Again this usually results as a result of human intervention. When nutrients are introduced into water, this can lead to population explosions of algae and other aquatic plants. This leads to higher bacterial levels, and leads to lack of water clarity. The algae not only consumes large amounts of oxygen, but can also be outright toxic to marine life. This causes dead zones where other forms of marine life cannot survive.
An example of this is seen in the case study A Flood of Pigs (http://www.mhhe.com/Enviro-Sci/CaseStudyLibrary/Topic-Based/CaseStudy_AFloodOfPigs.pdf). As hog farms were flooded in North Carolina waste, dead pigs, and nitrogen was then washed into rivers and bays. This influx of waste created depleted oxygen zones that killed existing marine life. The dead zone was estimated to be an area of nearly 350 square miles.
Another pollutant of water supplies are naturally occurring minerals, metals, and salts. While these are naturally occurring chemicals have always mixed with water, the rates at which they do so now are greatly accelerated by manmade processes such as mining. At the increased rates of absorption into the water supplies, these chemicals can quickly reach toxic levels.
Metals are a highly toxic substance, and do not break down easily. Therefore they can accumulate in water and organisms that live there. As example of this is mercury. As mercury is introduced into marine food webs, it builds up through each level of the food chain. The mercury can than reach dangerous levels in top marine predators. Due to this cumulative effect it is advisable not to eat certain types of predator fish very often, to avoid mercury buildup in our own bodies. These metals can also be present outright in the water, especially near mining areas, making the water itself dangerous to consume.
Salts are also another source of pollution. Salt in low concentrations is non-toxic. However salt used for things such as melting ice off roadways can then leach back into water systems. The salt buildup can get so high that it reaches toxic levels, destroying fresh water ecosystems. Acids from industrial zones also contribute to water pollution. The amount of acidity can change the pH levels of water zones, damaging native aquatic life.
Of course there is also man-made chemicals that contribute to water pollution. Chemicals used in the creations of plastic and fertilizers are highly toxic and have often been improperly disposed of. These chemicals, which often will not degrade on their own, are often washed into water compartments where they then build up to dangerous levels.
With all the dangers to our water supplies, there is a growing belief that it is safer to consume bottled water. Unfortunately this is not always the case. Many experts feel that local tap water is often safer than bottled water due to stricter and more consistent monitoring of the water. Many brands of bottled water can come from relatively untested aquifers or is simply recycled tap water.
The largest source of water pollution in the United States is sediment. This is another naturally occurring source of pollution that reaches dangerous levels due to manmade projects that greatly speed up the cycle that dumps sediment into rivers. This sediment quickly fills lakes and rivers, which can bury plant and animal life present in the rivers. This sediment can travel through rivers and then buildup in oceans as well, causing pollution problems there. Another side effect of industrial areas is that it can have a broad impact on water temperatures. The sudden raising or lowering of water temperature can wreak havoc with marine life that is acclimated to expect constant or slowly changing temperatures.
Chapter 7- Global Nutrition
- Food Quantity
- Food Diversity
- Soil Quality
Chapter 7
Global Nutrition
A major issue facing the world is the number of starving or undernourished people in the world. What makes this large scale problem harder to comprehend is that there is more food than ever being produced in the world. In Chapter 7 we learn about global food production, and the issues still facing getting this food properly distributed, as well as the environmental effects of this production explosion.
Our food production today no longer depends on local farmers bringing their goods to the market. Agriculture is a big business, and it is always trying to use the latest advancements in technology to grow even more food for less costs. A prime example of where this is being done is Brazil. The Cerrado region, long thought to be low quality grasslands, has been transformed into a huge agricultural area thanks to advancements in farm equipment and knowledge of battling poor soil. While this has increased the amount of food available to the world, it has had its share of costs. The grasslands are being wiped out, losing a large ecosystem, and many family farms have been taken over and the people displaced.
As we amaze ourselves at how much food production has risen, we can then be sobered by the fact that 1 in every 8 people on the planet is chronically hungry. 90% of these people live in underdeveloped countries, and have neither the means or the money to access these surplus food supplies being produced. These people still literally live and die with the results of their local crops and animal herds. The ability to have adequate meals everyday is referred to as food security. It is becoming accepted that food security is important in multiple ways. It is estimated that these underdeveloped countries could increase their economic growth by $120 million per year if they could keep their workforce healthy with food security.
Famine also plays a large part in global nutrition. Usually the source of these famines can be traced back to political disruption rather than inadequate ability to produce food. People are forced to leave their crops out of fear, or have their food confiscated by military forces. These refugees then often converge in other areas where there is not enough food to support the sudden influx of people, leading to famine.
Food Quantity
Every human needs a balanced diet to be relatively healthy, and have the needed energy to be productive. However it is estimated that nearly half of the world's population is undernourished. This could mean vitamin or mineral deficiency as opposed to outright starvation.
Lack of essential vitamins and minerals can lead to a myriad of health problems, most of them that severely affect children. Vitamin A, something that is common in green leafy vegetables, is lacking in many people's diets. This can lead to blindness or neurological problems. Diseases related to lack of nutrition or protein affect many children in underdeveloped countries. The main food that sustains undernourished people are usually starchy foods that have little nutritional value. While science has food ways to try and combat the chronic malnutrition faced by many people, the opposition to these scientific methods is equally strong. Golden rice, a rice that is rich in Vitamin A, was introduced as a way to provide this missing nutrient to underdeveloped countries. The world reaction was mixed at best, as there are many who opposed Genetically Modified food, and others who didn't want to make the underdeveloped countries dependant on handouts from other countries (http://www.mhhe.com/Enviro-Sci/CaseStudyLibrary/Topic-Based/CaseStudy_GoldenRice.pdf).
On the flip side of global hunger is the growing epidemic of obesity. It is estimated that there are now more obese people than underfed people, 1 billion to 850 million. While food security helps keep people well nourished, imbalanced diets, can lead to obesity. Obesity increases risk of many other nutritional diseases, such as diabetes. In the United States, one of the most food secure nations in the world, 400,000 people a year die from obesity related causes. This is nearly the same amount of people who die from smoking related diseases. Food security alone isn't enough to ensure a proper balanced diet.
The largest current problem with global malnutrition appears to have more to do with food distribution rather than food production. Many countries produce an over abundance of food, and then ship this food to poorer countries. However the food there is often possessed by only a few, and does not reach many who need it. This food can also undercut local food economy, leaving local farmers with an inability to make a living. Even in wealthier countries food distribution is uneven, as nearly 40% of prepared food is disposed of rather than actually being consumed.
Food Diversity
Despite the rich diversity of food across the planet, humans rely on just a few major crops for the majority of our diet. Wheat and rice form staple foods for nearly 5 billion people. In the United States corn is the most consumed crop, whether directly, or indirectly. In addition to being a common food item, corn is also used in many processed foods, and is fed to livestock which is then consumed by humans.
In addition to grains being a part of the world's diet, meat consumption is also raising. As with agriculture, technological advances have allowed for more livestock to be raised on less food and less time than ever before. A large part of the world's grain sources actually go to feeding livestock. The massive amount of food used to feed livestock for meat consumption is an overall indicator of global wealth, since it costs much more to feed animals for consumption than to consume the feed directly.
Seafood is another source of food for much of the world. Fish is an excellent source of protein, and accounts for about 15% of protein consumed worldwide. In addition it is also the main source of protein for underdeveloped countries, as fish are more readily accessible than livestock. However, as with much of our other natural resources, fish are becoming harder to attain. Overfishing of many of the worlds natural fisheries have led to dwindling fish populations. In efforts to maximize the number of fish caught, habitats and other sea creatures are destroyed as they are caught up on nets and hooks intended for other fish. Aquaculture, or growing fish in controlled environments is becoming an increasing larger part of the fish supply. These have their own drawbacks however, as it's harder to sustain carnivorous fish in these environments, and they controlled areas make disease and waste products a danger to other species.
While it is good that enough food is being produced to provide food security for more people, there is also a cost for the increased production. Many environments are destroyed in order to make room for more agricultural space, and the pollution from these areas can be damaging to surrounding areas. In addition many of the drugs used to fight diseases in livestock are leading to new strains of pathogens that are more resistant that ever to antibiotic drugs. While we may enjoy the lower prices and ease of access to previously rare foods, we need to take into consideration the cost to the environment for what could be considered luxuries.
Soil Resources
While farmers are finding ways to maximize their crop yields, one of the natural resources they are using up to do so is soil. Soil contains minerals, decomposed organic materials, and living organisms. These contribute to providing a fertile environment for plants to grow in. Under ideal circumstances it takes a year to generate 1mm of fertile soil. We are going through soil at a much higher rate.
Soil consist of six components. There is sand and gravel, silts and clays, dead organic material, soil fauna and flora, water, and air. Various mixtures of these components lead to a variety of soils, some more ideal for growing crops than others. Generally deep black soils are rich in nutrients as they contain much decayed organic material, and are best for growing plant life.
Soil is complex and highly susceptible to outside influences. Dead plant matter is recycled by bacteria and microscopic life forms. These organisms are found in the first few centimeters of soil, where they create pockets of air as they burrow through the earth. Climate, topography, and the parent material of soil are also large influences on the quality of soil. In conditions that are too hot or cold, decomposition happens to slowly or too quickly to benefit plant life. In areas that are too steep, water runoff occurs too quickly, preventing the soil from drawing nutrients from the water, or even being washed away. Parent material is the bottommost layer of the soil, and dictates the primary makeup of the topsoil layer.
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| Soil Horizons (Principles of Environmental Science, p. 164) |
Soil is divided into layers, A, E, B, C, and the parent material. The majority of food produced depends on quality A soil. In fertile areas, the A soil can be up to 6 feet deep. However erosion and over farming has made these areas rare. Most soil has less than 1-2 feet of A layer, and desert areas have little to none. Fertile topsoil is an important natural resource, and steps must be taken to ensure that topsoil is renewed for continued plant production.
Chapter 11- Earth Processes
- Minerals and
- Geology and Mineralogy
- Effects of Resource Extraction
- Conserving Resources
- Geologic Hazards
Chapter 11
Earth Processes
Earth processes are descriptive of how dynamic our planet is. The earth's crust is constantly moving, and occasionally tectonic plates will collide or rub against each other, causing earthquakes. The earth consists of a solid inner core, a fluid outer core, and a mantle. These features are then covered by the earth's crust.
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| Earth's Layers (Principles of Environmental Science, p. 272) |
The earth's crust is broken into sections called tectonic plates. These plates are constantly moving and shifting, forming new landmasses over millions of years. Magma from the earth's core comes up through cracks in the earth's crust, and forms underwater mountain ranges. These underwater mountain ranges have higher peaks and lower valleys than any mountain ranges on the surface of the earth. As an example of how much these tectonic plates move, Australia and Antarctica were thought to have once been a part of Africa before breaking apart and moving thousands of miles away over millions of years.
Minerals and Rocks
Minerals are inorganic solids that make up crystal structures. The kind of mineral formed depends on the chemical composition. Metals are created from minerals, but are no longer crystalline after being smelted, so are no longer minerals. Rocks are combinations of minerals held together in a solid mass, forming a larger overall structure.
There are three basic kinds of rocks, igneous, metamorphic, and sedimentary. The names refer to how the rocks were formed. Igneous rocks are formed by lava that cools. Metamorphic rocks form over time as they are molded by the tectonic plates folding and heating them. Sedimentary rocks form when loose minerals are consolidated over time, but without the extreme pressure or head of igneous or metamorphic rocks. The way these rocks are formed is referred to as the rock cycle.
Over time rocks are broken down by weathering. This can occur mechanically or chemically. Mechanical weathering refers to rocks being broken down naturally over time by water. Chemical weathering occurs when water mixes with acids and changes the makeup of the rock. These makes the rocks more susceptible to mechanical weathering. The particles from these rocks are then transported by wind and water to form deposits of sedimentation.
Geology and Mineralogy
One of the features of earth that makes it unique, other than the presence of life, is the rich mineral diversity found on the planet. There are currently over 4,400 different types of minerals, far more than have been found on neighboring planets. The reason for this is thought to be the combination of the movement of tectonic plates, and the presence of oxygen. The movement of the plates has allowed concentrations of minerals to crystallize and form new minerals. Oxygen released by plant life over millions of years has also oxidized minerals, creating new varieties. Harvesting of these minerals is a profitable business, as these minerals are used in much of the products we produce.
Metals are valuable due to their malleable nature, light weight, and strength. Iron is the most consumed metal, followed by aluminum, manganese, copper, and nickel. These metals have great economic value, and are widely traded on the global market. Like all resources however, there is a finite limit to their availability.
Minerals are also important economically. Minerals provide everything from the ability to create glass, treat acidic soil, creating roads, and building materials. Minerals also form gemstones, which are often quite valuable, and actively used for trade and transportation of wealth. Diamonds are an example of valuable gemstones, and also an example of the extreme measures humans will go through to acquire them. Violence, wars, and other humanitarian crimes are carried out in order to acquire these gemstones.
Natural gases are also a highly valued natural resource. Deposits of oil, coal, and natural gas provide much of the energy that modern countries use every day. These resources are also finite, and research is underway to try and find alternative energy sources that are renewable, environmentally friendly, and more cost efficient.
Effects of Resource Extraction
We use all of these minerals and natural gasses in our daily lives, as they are used to create everyday items such as glass, plastic, and electronics. Reliance on these items means we need to constantly be harvesting these resources, and that can have adverse effects on the environment. Water and air pollution are serious by-products of mining, as the methods used to obtain minerals and metals often leave toxic chemicals behind. These chemicals then become airborne or make their way into water sources.
There are several methods of mineral extraction currently being practiced, and all have cause varying degrees of damage to the environment. Some common forms of mining are underground mining, placer mining, well drilling, strip mining, and mountain top removal. All these methods cause varying degrees of damage to the environment, and some leave toxic lakes and slag piles that can contaminate areas for years. It is currently estimated that in the in United States alone over 12,000 miles of rivers and streams are currently contaminated by mining runoff. The estimated cost of cleaning up these areas is currently $70 billion dollars. Mining companies are currently working on developing new methods of extraction that are less damaging or easier to reclaim the environment.
After the minerals are extracted from the ground, the rock ore is then smelted to extract the precious metals. These methods are just as damaging to the environment if not more so than the extraction from the earth. Heating of the ore can produce massive air pollution, and spreading of toxic chemicals that can destroy life and vegetation. Other methods of extraction include soaking piles or ore in chemical baths. These chemical containers are supposed to keep the chemicals from being absorbed into the ground, but leaks are common.
Conserving Resources
As we have come to the realization that there are a finite amount of resources available, and the extreme damage done to the environment to acquire those resources, there have been efforts to promote conserving our existing resources. One way this is done is by recycling metals and products that have already been extracted or produced. This allows us to save money and energy on extraction of new materials, and often times recycling the materials has a significantly smaller environmental footprint than the original extraction. Two prime examples of this are aluminum and steel. Aluminum can be reclaimed from recycled materials at a fraction of the cost that it takes to harvest new aluminum. There are new minimills which can reform scrap iron and steel and again run at a fraction of the cost of a traditional steel mill that is creating the steel from scratch. New United Stages regulation require that all new steel must contain at least 28% recycled material.
In addition to recycling old materials, advances in manufacturing fields have allowed for the creation of new materials that require less raw metals or minerals. This phasing out of heavy reliance on metals such as iron or steel will hopefully curb the need to mine these raw materials, and not have to damage the environment further.
Geologic Hazards
As we learned earlier the earth is constantly in motion. Tectonic plates collide and cause seismic events. These events have shaped the earth as we know it today. These are incredible forces at work, and they still happen, sometimes with devastating results to the human population.
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| Tsunami Devistation |
Earthquakes are unpredictable and can hit with devastating suddenness. On March 11, 2011 a 9.0 magnitude earthquake struck off the coast of Japan, and caused a tsunami that had waves that reached 30-feet in height (http://www.huffingtonpost.com/2012/02/27/japan-earthquake-anniversary-photos_n_1303476.html?ref=japan-tsunami). The earthquake and tsunami claimed over 19,000 lives, and caused up to $300 billion dollars of damage. In 2004 a tsunami near Indonesia killed over 230,000 people. These earthquakes occur when edges of tectonic plates push past one another. If the plates have trouble passing one another, the pressure builds up until there is a giant release, which results in an earthquake. It is recently being discover that geologic activity by humans can also possibly lead to seismic activity, resulting in man-made earthquakes.
Volcanoes are another natural feature on earth that has helped to form earth as we know it today. Without volcanoes we might not have as much fertile soil for agriculture, as volcanic ash has formed the basis for many of these fertile areas. These volcanic eruptions can cause large amounts of damage and disruption to the environment. Ash and gas from volcanoes can remain in the atmosphere for years, causing damage to the atmosphere and even affecting global temperatures. Populations that have not heeded warning signs of impending volcanic eruptions have often paid a heavy price as well, as an eruption can happen so quickly and spew toxic gases in the air that anyone in the surrounding area has little chance of survival.
Floods are another naturally occurring geologic event that can do much damage to human populations. While people have settled next to rivers due to the convenience provided, they are usually making their homes in known flood plains. These flood plains may not flood constantly, but have flooded before and are likely to flood again. Floods can be sudden and severe, but also do lasting damage as the waste and silt carried by the water can contaminate wide areas, making it difficult for people to survive with no fresh water sources. The damage done by the floods also has high monetary costs, as these areas are usually also associated with agricultural, and the loss of crops can be damaging to the global economy. There are signs that global warming can also trigger these floods, as it affects rainfall patterns, and can cause severe rain in unexpected areas. Human measures taken to diminish flood damage has had some success, but can oftentimes make floods worse than they would have originally been. Flood controls structures are designed to keep water moving, however when water continues to accumulate and swell, eventually one of these structures will fail, and the damage will be disastrous in the area where the water finally breaks through.
Landslides also can cause property damage and loss of life. Especially in areas where land is expensive, people will build in unsafe areas. These areas can also become more prone to landslides due to terrain deformation that can occur from activities such as logging or mining. These landslides can occur quickly and can destroy anything in its path.
Naturally occurring erosion can also cause massive damage to man-made structures. As people like to build in areas right near water, the ground they build on is often unstable and susceptible to flooding. In the United States the government contributes to this by providing disaster insurance that will rebuild houses lost to flooding, but only if it is constructed in the same area. This can lead to a constant cycle of houses being destroyed and rebuilt at increasing cost to the general public. Building in these areas can also contribute to environmental damage, as the buildings can interfere with natural vegetation that would normally protect these areas from erosion or flood damage.
While the global economy currently depends on harvesting the earth's resources, the damage being done to retrieve these resources may never be undone. Going forward we need to make aware decisions on how we can personally contribute to preserving our environment, and also which policies we choose to support on a global scale.
