The planet can only support so many people before natural resources begin to become depleted and cannot support human needs, called Earth’s carrying capacity for humans. Many geographers and other scientists believe that humans have grown beyond earth’s carrying capacity; a concept called overshooting. In less developed countries, this has occurred because of population growth; in more developed countries, it has to do with our consumption of natural resources. A natural resource is something found within the natural environment that is accessible and economically valuable to humans, including food, water, soil, plants, animals, and minerals. However, most resources are not renewable, and humans are either consuming them faster than the planet can replenish them or in the case of water and air are polluting them.

13.1 Depletion of Natural Resources

There are primarily two types of resources: energy and minerals. As noted, a natural resource only has “value” as long as humans need it. As it turns out, humans need more and more energy and mineral resources, resulting in increased costs. There has also been a steady rise in the cost of petroleum, gold, copper, platinum, and titanium.

Throughout history, most of the world’s energy came from animate power; the use of animals such as mules, ox, and horses. However, following the Industrial Revolution, most of the energy in Europe and the United States was used for machinery. The energy used to power the machinery came from inanimate power such as biofuel and fossil fuels. Currently, the most used energy source for less-developed nations is biofuels, such as trees, coal, and methane. However, in more developed nations and nations transitioning, fossil fuels have become the central source of energy.

Mining

Deforestation

The planet’s growing population has increased demands on natural resources, including forest products. Humans have been using trees for firewood, building homes, and making tools for millennia. Trees are a renewable resource, but deforestation occurs when they are removed faster than they can be replenished. Most people in rural areas in developing countries rely on firewood to cook their food. Many of these areas are experiencing a fast decline in the number of trees available. People living in mainly type B climates may not have access to many trees to start with; therefore, when trees are cut down for firewood or building materials, deforestation occurs. In the tropical areas, it is common for hardwood trees to be cut down for lumber to gain income or to clear the land for other agricultural purposes, such as cattle ranching. Countries that lack opportunities and advantages look to exploit their natural resources – in this case, trees – for either subsistence agriculture or economic gain. Deforestation has increased across the globe with a rapid rise in the worldwide population.

During the Industrial Revolution, European countries chopped down their forests at a rapid rate. Much of the British Isles was forested at one point, but today few forests remain on the British Isles, and they are typically protected. Colonialism brought the Europeans to the Americas. The United States, in its early development, pushed west from the original thirteen colonies, and many old-growth forests were cut down in the process. As railroad tracks were laid down and pioneer development pushed west into the Great Plains, where there were few trees, the great cutover occurred in the eastern and central forests – cutover is a term indicating the systematic deforestation of the eastern and central forests. Michigan and Wisconsin saw their trees removed in systematic deforestation.

Some areas were allowed to grow back, but many other areas were turned into farmland. Few old-growth forests remain in the United States. Today there are conflicts over how the timber industry is handling the forests in places such as the Pacific Northwest region of the United States.

Countries that are better off economically no longer have to cut down their trees, but can afford to substitute other resources or import lumber from other places. Developing regions of the world in Latin America, Africa, and parts of Asia are experiencing severe problems with deforestation. Deforestation is widespread: Residents of Haiti have cut down about 99 percent of the country’s forests; most of the wood has been used as fuel to cook food. People in Afghanistan have cut down about 70 percent of their forests. Nigeria has lost about 80 percent of its old-growth forests since 1990. Ethiopia has lost up to 98 percent of its forested acreage, and the Philippines has lost about 80 percent of its forests.

Brazil’s Amazon basin has undergone many projects that have driven deforestation. For example, about half the state of Rondônia in western Brazil has been deforested since 1990. The countries of Central America have lost about half their original forests, and deforestation continues on a systematic basis. Tropical regions of Southeast Asia and Africa are being exploited for their timber at unsustainable rates, causing deforestation that the next generation will have to address. India, with over a billion people, still has a high demand for firewood and building materials; their forests are declining faster than they can be replanted. China, with its billion-plus population, has been attempting to address its deforestation problems by implementing a massive replanting program and conservation measures. Other countries are starting to adopt similar measures.

Tropical rain forests only makeup about 5 percent of the earth’s surface but contain up to 50 percent of the earth’s biodiversity. These forests are cut down for a variety of reasons. Norman Meyers, a British environmentalist, estimated that about 5 percent of deforestation in tropical regions is caused by the push for cattle production. Nineteen percent of these forests are cut down by the timber industry, 22 percent are cut down for the expansion of plantation agriculture, and 54 percent are removed due to slash-and-burn farming. Most tropical rain forests are located in the Amazon basin of South America, in central Africa, and Southeast Asia. All these areas are looking for advantages and opportunities to boost their economies; unfortunately, they often target their tropical rain forests as a revenue source.

Deforestation causes more than the loss of trees for fuel, building materials, paper products, or manufacturing. Another related issue in the deforestation equation is soil erosion. Without the trees to hold the soil during heavy rains, soils are eroded, leaving the ground in an unproductive state. In tropical areas, soils are often degraded and lack nutrients. Most of the nutrients in the tropical areas rest in decaying material at the base of the trees that supply energy back into the ecosystem. Once the trees are removed, there is little replenishing of this energy supply. Soil erosion in tropical areas makes it hard for forests to grow back once they have been removed. Landslides can be a more severe component of the soil erosion problem. After heavy rainfall, entire hillsides saturated with water can slide downward, causing severe structural damage to buildings, homes, and agricultural plots. Tree roots help hold hillsides together and therefore help prevent landslides.

Forests play an essential role in the water cycle. Trees pull up moisture with their roots from the soil and transpire it through their leaves back into the atmosphere. Moisture in the atmosphere collects into clouds, condenses, and falls back to Earth. Not only do trees store water, but the organic matter at the base of the trees also stores water and makes it available to the broader ecosystem, which may slow down water runoff. Forest canopies disperse water during rainfall and create another layer of moisture in their leaves and branches, which either is used by other organisms or evaporates back into the atmosphere. Deforestation eliminates the role that forests play in the water cycle.

Forest ecosystems provide for a diverse community of organisms. Tropical rain forests are one of the most vibrant ecosystems on the planet. Their abundant biodiversity can provide insight into untapped solutions for the future. Plants and organisms in these habitats may hold the key to medical or biological breakthroughs, but wildlife and vegetation will be lost as deforestation eliminates their habitat and accelerates the extinction of endangered species.

Trees and plants remove carbon dioxide from the atmosphere and store it in the plant structure through the process of photosynthesis. Carbon dioxide is a significant greenhouse gas that is a part of the climate change process. Carbon dioxide and other similar gases reduce the amount of long-wave radiation (heat) that escapes from the earth’s atmosphere, resulting in increased temperatures on the planet. As more carbon dioxide is emitted into the atmosphere, climate change occurs. The removal of trees through deforestation results in less carbon dioxide being removed from the atmosphere, which contributes to climate change. Slash-and-burn farming methods that burn forests release the carbon in the plant life directly into the atmosphere, increasing the climate change effect.

Fossil Fuels

Everything that is or was alive is made out of carbon. Millions of years ago when the planet was a lot warmer, plant life was quite abundant. Over geologic time, these carbon bodies were buried and ultimately converted to fossil fuels (i.e., coal, petroleum, and natural gas). When you fill your car up at the gas station, you are technically putting ancient plant life into your vehicle. When you drive off, that fuel is burned, and the ancient carbon is released into the environment in the form of carbon dioxide.

There are two concerns about fossil fuels. One is that the carbon dioxide released is a greenhouse gas, and the other is that it is considered a finite resource. A natural resource is considered a renewable resource if nature can reproduce it within a human lifetime. So energy sources such as solar energy, wind power, and geothermal are considered renewable energy sources. Fossil fuels are not considered renewable because it requires millions of years for the earth to replenish them. So ultimately, humans will run out of fossil fuels, but the question is when. In terms of coal, the world has well over 200 years worth, but with petroleum, the question becomes more complicated.

Currently, there are over a trillion barrels of petroleum, called proven reserves, that we are aware of with current technology. Potential reserves are resources of petroleum not discovered yet by society. Currently, there is much concern about how many reserves of petroleum are left to discover. Technology today is allowing the industry to discover reserves deeper than ever before and tap into petroleum reserves in ways never allowed before.

Uneven Distribution

Another global problem in terms of fossil fuels is that it is not found uniformly around the planet. Coal forms in tropical regions where there are lots of vegetation and swamps. As the vegetation falls into oxygen-poor water, it is converted into a carbon-based rock over geologic time. Because of plate tectonics, the slow movement of continents around the planet, most of the mid-latitude countries such as China, Russia, and the United States were located near the equator 250 million years ago. Today these countries have abundant amounts of coal. Petroleum and natural gas forms on the ocean floor under high pressure from overlying water and sediment. Some of these areas are still underwater, such as in the Persian Gulf and the Gulf of Mexico. Other regions are no longer underwater such as the Middle East.

Most of the world’s sources of fossil fuels exist in more developed countries, which has much helped in their development. Today the United States and China are the largest consumers of fossil fuels on the planet. In the 21st century, the demand for coal, petroleum, and natural gas will shift to less-developed nations as they move through the demographic transition model.

The majority of the world’s petroleum prices is determined by As noted earlier, mid-latitude countries such as the United States, Russia, and China have the most abundant supply of coal. In terms of petroleum, the mission of the Organization of Petroleum Exporting Countries (OPEC) “is to coordinate and unify the petroleum policies of its Member Countries and ensure the stabilization of oil markets in order to secure an efficient, economic and regular supply of petroleum to consumers, a steady income to producers and a fair return on capital for those investing in the petroleum industry.”

In the 1970s, there was a global energy crisis. This occurred when Arab countries of OPEC were angered by Europe and the United States’ support over Israel during the 1973 war with Egypt, Jordan, and Syria. The Arab OPEC members refused to supply oil to the United States, which immediately created a fuel shortage. During the 1980s and 1990s, prices of oil dropped dramatically, stimulating global economies all around the world. After the fall of the Soviet Union, Russia struggled to survive as a modern society. However, starting in the late 1990s, Russia began exporting its petroleum and coal resources and its political, economic, and military power grew substantially. Cheap fuel in the United States spurred the automotive industry to build large SUVs with low miles-per-gallon. However, the mid-2000s saw a sharp increase in fuel prices with record prices occurring in the summer of 2008. Following the summer of 2008, SUV sales plummeted risking the possibility of Ford and GM becoming extinct.

Nonrenewable Substitutions

With the increase of oil in the last few years, there has been a desire to find alternatives. There have been a sharp increase in natural gas vehicles because natural gas is cheaper and pollutes less than oil. However, the underlying economics of supply and demand state that as natural gas is used more (demand), the cost is likely to follow.

Since the world has plenty of coal to last hundreds of years, some have pushed more coal burning. There are several environmental concerns with coal. First, coal is the “dirtiest” fossil fuel in terms of air pollution. Burning coal releases vast amounts of sulfur, which creates acid rain and mercury, which damages our neurological system. It also releases the most substantial amount of carbon dioxide, which is a greenhouse gas. With the current concern with global warming, there have been many talks about carbon sequestration. The idea behind this is that if humans can capture the carbon dioxide before it is released, we might be able to “lock” it deep within the earth and thus preventing it from contributing to global warming. However, the technology here is far from proven yet.

The third source of nonrenewable energy is nuclear. Since Chernobyl in 1986 in the former Soviet Union and the Three-Mile Island incident in the United States, our country has been very apprehensive in creating new nuclear power plants. The benefit of nuclear power is that incredible amounts of energy can be generated without polluting the environment. There are serious concerns about potential accidents and the radioactive waste it generates. There has been a recent heated debate in the West as to where to store radioactive waste. In Utah, there have been conversations regarding the storing of nuclear waste at the Goshute Indian Reservation as a short-term stop to Yucca Mountain in Nevada. However, many in Utah believe that a nuclear waste, which takes tens of thousands of years to decompose, in Utah will never leave even though we do not have a nuclear power plant. In Nevada, there is concern about the actual safety of storing nuclear waste in a mountain with nearby fault lines. Moreover, after the September 11 terrorist attacks, there is renewed interest in nuclear power plants becoming targets.

Natural Substitutes

With the increase of oil in the last few years, there has been a desire to find alternatives. There have been a sharp increase in natural gas vehicles because natural gas is cheaper and pollutes less than oil. Basic economics of supply and demand state that as natural gas is used more (demand), the cost is likely to follow.

Since the world has plenty of coal to last hundreds of years, some have pushed more coal burning. However, there are several environmental concerns with coal. First, coal is the “dirtiest” fossil fuel in terms of air pollution. Burning coal releases vast amounts of sulfur, which creates acid rain and mercury, which damages our neurological system. It also releases the most significant amount of carbon dioxide, which is a greenhouse gas. With the current concern with global warming, there have been many talks about carbon sequestration. The idea behind this is that if humans can capture the carbon dioxide before it is released, we might be able to “lock” it deep within the earth and thus preventing it from contributing to global warming. However, the technology here is far from proven yet.

The third source of nonrenewable energy is nuclear. Since Chernobyl in 1986 in the former Soviet Union and the Three-Mile Island incident in the United States, our country has been very apprehensive in creating new nuclear power plants. The benefit of nuclear power is that incredible amounts of energy can be generated without polluting the environment. However, there are serious concerns about potential accidents and the radioactive waste it generates. There has been a recent heated debate in the West as to where to store radioactive waste. In Utah, there has been talking of storing nuclear waste at the Goshute Indian Reservation as a short-term stop to Yucca Mountain in Nevada. But many in Utah believe that a nuclear waste, which takes tens of thousands of years to decompose, in Utah will never leave even though we do not have a nuclear power plant. In Nevada, there is concern about the actual safety of storing nuclear waste in a mountain with nearby fault lines. Moreover, after the September 11 terrorist attacks, there is renewed interest in nuclear power plants becoming targets.

13.2 Environmental pollution

Pollution of the environment occurs when humans contaminate the air, water, or land. Pollution can also be broken down into two categories: primary and secondary. Primary pollution is when humans directly contaminate the earth in some manner. Examples include mercury, sulfur, and even carbon dioxide. Secondary pollution happens when a primary pollutant reacts with another primary pollutant, sunlight, and water to create a different pollutant.

An example is acid rain. Sulfur dioxide is a primary pollutant, but when it reacts with precipitation is becomes a secondary pollutant called acid rain. One of the biggest problems with pollution is that those who pollute are usually not the ones affected by it; instead, the down-winders are.

Air Pollution

The atmosphere is mostly made of 78 percent nitrogen, 21 percent oxygen, and small percents of other trace molecules such as ozone, carbon dioxide, water vapor, and aerosols. Air pollution occurs when humans add unnatural substances into the atmosphere. Most of the air pollution from the industry comes from coal, while automotive pollute vast amounts of ozone, carbon dioxide, and sulfur into the atmosphere. However, in the 1970s, the United States created the Clean Air Act, which has dramatically enhanced the quality of our nation’s air. Check out this video from National Geographic on the world’s air quality.

Those who pollute are usually not the ones affected by it. Industrialization in eastern North American and eastern Europe have generated large-scale pollutants such as sulfur oxides and nitrogen oxides through the burning of fossil fuels. When these pollutants react with water, they form acid precipitation. Acid precipitation can cause large-scale damage to aquatic life and forests by making the vegetation very sick and dying. In forests, this can lead to disease through pest infestation. Acid precipitation can also damage or destroy buildings and monuments made out of marble such as tombstones.

Ozone Hole

In the 1920s, humans developed a chemical called chlorofluorocarbons (CFCs) for things such as refrigerating and air conditioners. However, in the 1970s, two American scientists discovered that these CFCs were weakening the ozone hole. What they learned is that when the CFC’s reach the layer of the ozone hole, the ultraviolet radiation from the sun breaks the chlorine off which can attach and destroy over 100,000 ozone molecules and continue in the upper atmosphere for over 100 years. Over time and much debate, the world got together and signed the Montreal Protocol in 1987 to phase out CFCs. Today, most industrialized countries have eliminated the use of CFCs, but the ozone hole is not required to heal for another 50-100 years. Learn more about what is currently going on with the ozone hole at NASA’s Ozone Hole Watch.

Water Pollution

Water is the most valuable resource on the planet, but humans keep polluting it in various ways. Manufactures use water to create and process food. Farmers pollute vast amounts of water through fertilizer and waste from pigs and cows in unhealthy feedlots. Water is used by coal powerplants to extract and wash coal, along with cooling the steam used to make electricity. All of these processes, along with residential use, have negative impacts on water quality.

Water pollution can significantly harm aquatic life in rivers, lakes, and the ocean. Many of the fertilizers in farmers and the cleaners we use can create algae blooms in our local rivers. When the algae die, it can also remove the oxygen from the water, which can kill fish and other aquatic life. These are called dead zones, and one of the biggest in the world is forming in the Gulf of Mexico because of the pollution in the Mississippi River. Just like our air, the nation’s water has dramatically improved since the 1970s because of the Clean Water Act.

Plastics

13.3 Renewable resources

Humans cannot sustain the path we have been traveling with our consumption of resources, and a global population expected to peak at 9 billion by 2050. We need to learn how to live differently without decreasing our quality of life. One such possibility is to move towards a renewable energy economy. The following are the diverse types of renewable energy.

Biomass

Biomass is when humans burn vegetation as a fuel source. Many argue that this not a viable option for human energy consumption. Burning biomass releases large amounts of carbon dioxide into the atmosphere and requires the destruction of ecosystems such as deforestation. There has also been a recent push for ethanol as a “green” source of energy. In the United States, corn has been used and subsidized to make ethanol. The effects have been a spiraling rising in the cost of corn-based food. Plus many would argue that humans should not be using food for fuel when humans are now consuming more food than we are producing. In Brazil, they are using sugarcane to produce ethanol. Because there is much money to be made in the ethanol industry, Brazil is cutting down the Amazon rainforest to produce more sugarcane for its energy economy. So it can be argued that ethanol is not “green” energy if it requires deforesting the rain forests along with causing food prices to rise.

Hydroelectric Power

Hydroelectric power is also questionable as an energy source even though it is renewable. Hydroelectric power requires dams being built in order for flowing water to turn turbines within the dam to generate electricity. There are numerous problems with power coming from hydroelectric dams. It requires flooding usable and often time fertile land to create a lake. Over time, the lake can fill up as sediment gets deposited into the lake. Dams can also harm aquatic wildlife such as salmon because they prevent them from returning to their spawning locations. Many northwestern states in American have dismantled damns because salmon are near extinction. However, it must be said that it is “clean” energy in that hydroelectric power does not pollute the air or water.

Wind Power and Geothermal Energy

Windmills have been around for hundreds of years, but only recently have they been used to generate electricity. Until last year, wind power was the fastest-growing energy source in the world. Moreover, with the rising costs of fossil fuels, wind power is now cheaper to produce than energy from fossil fuels. Farmers are getting onboard with wind power because power companies will rent space to place the windmills, which will provide a steady income for the farmer. However, the farmer can still grow their crops or have their cattle and maintain their way of life. The energy created by wind is similar to dams because the wind turns the blades, which turns a turbine within the windmill to generate electricity.

There are a few concerns with wind power, however. Some do not like how windmills look because they require being out in the open; whereas coal power plants are easier to hide behind mountains. There is also concern that windmills can harm migratory birds and bats. However, wildlife is more likely to be hurt by changing climates than by small-scale windmills. Now out in Europe, they have been earnest about wind power. Some of the windmills along the continental shelf, where the winds are steadily consistent, have windmills so giant they can land a helicopter on them. They are so large that each blade is over 300 feet long (said another way, each blade is taller than the Statue of Liberty). The United States is still far behind other countries in Europe, but that is starting to change. It is now possible to purchase wind power from various energy companies. The most extensive wind power program in the United States is called the Blue Skies Program by Rocky Mountain Power.

The Earth’s interior is still sweltering because of Earth’s formation. A new technique being implemented is to use water and the internal heat the earth to produce steam, which can turn turbines to generate electricity. It requires using existing groundwater or pumping groundwater into the earth so the heat can evaporate the water into steam and turn a turbine. The image below is a geothermal plant in Iceland where they plan to use the heat from their volcano (Iceland is a volcanic island) to power their entire country.

Solar Energy

With the sun still having 5 billion years of life, our star is the ultimate renewable energy source. There are two types of solar energy: passive and active. Passive solar energy requires no special devices, rather south-facing windows and dark surfaces to light and heat buildings. This is a very inexpensive alternative, and, surprisingly, it is not used more often. Active solar energy captures heat and generates electricity by using photovoltaic cells with solar panels. The panel’s cells are made from silicon, which is the second most abundant mineral on Earth’s crust and when combined with other materials become sensitive to sunlight, called the photovoltaic effect. The electrons within the cells move through the silicon and produce an electrical current. In 2008 solar panels surpassed windmills as the fastest-growing energy source in the world.

Recycling

There has also been a steady demand to recycle rather than through products into our landfills. However, recycling is not only about saving landfill space; it is about water, natural resources, and energy. It requires less energy, water, and natural resources from the earth to re-create something than to mine and process the raw material. Take a soda can. How long do you keep a soda can once you open it? Did you know that it may take up to three years for the material to be mined from the mountain, processed, shipped, filled with soda, and shipped to you? This requires a lot more energy than we typically consider, and learning to recycle projects does more than just savings than just landfill space.

There is now a variety of ways someone can recycle. Many cities around the nation have curbside recycling. There are also several drop-off sites, which are often found at retail and grocery stores. Buy-back centers are commercial businesses that purchase recyclable goods. However, it is important to note that what you can recycle varies based on the recycling company. Therefore citizens must learn what products can be recycled for your geographic area.

13.4 Sustainable Development Goals

Sustainable Development Goals

The ideas behind sustainable development can be traced back to early works of scholars such as Rachel Carson’s Silent Spring (1962), Garret Hardin’s Tragedy of the Commons (1968), and Paul Ehrlich’s Population Bomb (1971). Despite different focuses of these classic works related to population and environment, all raised public concerns over environmental problems from human activities and highlighted the importance of systems thinking.

Some tremendous efforts and notable achievements have been made towards sustainable development but are our contemporary civilization sustainable? It turns out that in many ways, it is not. The basic idea of unsustainable development is that there are some things that we are doing today that we cannot continue doing forever. Much of our development depends on natural resources that either cannot be replaced or that are not being replaced as fast as we are depleting them. Some major examples are:

• Fossil fuels (oil, coal, and natural gas) used for energy
• Freshwater supplies used for irrigation and drinking
• Minerals used for manufacturing
• Trees used for construction and fuel
• Fish used for food

Each of these resources is becoming increasingly scarce. We cannot continue using them as we do today. Either we will need to shift away from them on our own, or shortages will force us to change our ways.

There are other reasons why some aspects of contemporary development may be considered unsustainable. Development is changing the global climate system and affecting biodiversity in ways that could have very perilous consequences. We need to note that if we try to continue with development as we have been, then the ensuing changes to climate and biodiversity could eventually prevent us from maintaining our state of development. Finally, as we saw on the previous page, development even today is not necessarily something to be desired. On the other hand, development involves much of what is important to us and thus is not something we can easily walk away from. Achieving development that is both desirable and sustainable is an important goal for our lives and our society.