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.
8.1 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.
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.
8.2 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.
8.3 Anthropocentric Climate Change
Weather and Climate
When it comes to defining climate, it is often said that “climate is what you expect; weather is what you get.” That is to say; climate is the statistically-averaged behavior of the weather. In reality, it is a bit more complicated than that, as climate involves not just the atmosphere, but the behavior of the entire climate system—the complex system defined by the coupling of the atmosphere, oceans, ice sheets, and biosphere. Weather is the current conditions of the atmosphere for a specific location and time.
Having defined climate, we can begin to define what climate change means. While the notion of climate is based on some statistical average of the behavior of the atmosphere and ocean, this typical behavior can change over time. That is to say, what you “expect” of the weather is not always the same. For example, during El Niño years, we expect it to be wetter in the winter in California and snowier in the southeastern U.S., and we expect fewer tropical storms to form in the Atlantic during the hurricane season. So, the climate itself varies over time.
If the climate is always changing, then is climate change by definition always occurring? Yes and No. A hundred million years ago, during the early part of the Cretaceous period, dinosaurs roamed a world that was almost certainly warmer than today. The geological evidence suggests, for example, that there was no ice even at the North and South poles. Climate change is a naturally occurring process of the planet, following a variety of different cycles. Something else is occurring that is causing the planet to warm
So, the significant climate changes in Earth’s geologic past were closely tied to changes in the greenhouse effect. Those changes were natural. The changes in greenhouse gas concentrations that scientists talk about today are, however, not natural. They are due to human activity.
The scientific consensus demonstrates that climate change in the 21st century is necessarily a human problem. People are causing climate change through their everyday actions and the socioeconomic forces underlying those actions. At the same time, people are feeling the consequences of climate change through various impacts on things they value, and through the responses, they are making to address climate change.
Climate is the average of weather (typically precipitation and temperature) in a particular location over a long period, usually for at least 30 years. A location’s climate can be described by its air temperature, humidity, wind speed and direction, and the type, quantity, and frequency of precipitation. Climate can change, but only over long periods. The climate of a region depends on its position relative to many things.
Scientific Consensus
The scientific consensus is clear, in that 97 percent of all scientists who directly study climates and climate change believe that the current warming of the planet is anthropogenic (human) in nature. Moreover, all of the scientific evidence and planetary vital signs indicate that more greenhouse gases are trapping Earth’s heat, causing average annual global temperatures to rise. While temperatures have risen since the end of the Pleistocene, 10,000 years ago, this rate of increase has been more rapid in the past century and has risen even faster since 1990. The nine warmest years on record have all occurred since 1998, and NASA and NOAA reported in 2019 that the year 2018 was the fourth warmest ever recorded on the planet. The 2010-2020 is predicted to be the warmest decade yet, followed by 2000-2010.
The United States has long been the largest emitter of greenhouse gases, with about 20 percent of total emissions. As a result of China’s rapid economic growth, its emissions surpassed those of the United States in 2008. However, it is also essential to keep in mind that the United States has only about one-fifth the population of China. What is the significance of this? The average United States citizen produces far more greenhouse gases than the average Chinese person.
Predicted Future Warming
Climate change can be a naturally occurring process and has created environments much warmer than today, such as the early Cretaceous period. During this time, life thrived even in regions, such as the interior of Antarctica, that is uninhabitable today.
One misconception is that the threat of climate change has to do with the absolute warmth of the Earth. That is not, in fact, the case. It is, instead, the rate of change that has scientists concerned. Living things, including humans, can quickly adapt to substantial changes in climate as long as the changes take place slowly, over many thousands of years or longer. However, adapting to changes that are taking place on timescales of decades is far more challenging. However, the planet is warming at such a rate that most species, especially mammals, will struggle to adapt and evolve quickly enough to the coming warmer climates.
The natural increase in atmospheric carbon dioxide that led to the thaw after the last Ice Age was an increase from 180 parts per million (ppm) to about 280 ppm. This was a smaller increase than the present-time increase due to human activities, such as fossil fuel burning, which thus far have raised CO2 levels from the pre-industrial value of 280 ppm to a current level of over 410 ppm – a level which is increasing by 2 ppm every year. So, arguably, if the dawn of industrialization had occurred 18,000 years ago, we may very likely have sent the climate from an ice age into the modern pre-industrial state.
How long it would have taken to melt all of the ice is not precisely known, but it is conceivable it could have happened over a period as short as two centuries. The area ultimately flooded would be considerably more significant than that currently projected to flood due to the human-caused elevation of carbon dioxide that has taken place so far. Below is a video from Science Insider on what the planet would like today if all the glaciers melted.
By some measures, human interference with the climate back then, had it been possible, would have been even more disruptive than the current interference with our climate. That interference would merely be raising global mean temperatures from those of the last Ice Age to those that prevailed in modern times before industrialization. What this thought experiment tells us is that the issue is not whether some particular climate is objectively “optimal.” The issue is that human civilization, natural ecosystems, and our environment are heavily adapted to a particular climate — in our case, the current climate. Rapid departures from that climate would likely exceed the adaptive capacity that we and other living things possess, and cause significant consequent disruption in our world.
The amount of carbon dioxide levels will continue to rise in the decades to come. However, the impacts will not be evenly distributed across the planet. Some of those impacts will depend on environmental and climate factors; other impacts will be dependent on whether the countries are developed or developing. Scientists use sophisticated computer models to predict the effects of greenhouse gas increases on climate systems globally for specific regions of the world.
If nothing is done to control greenhouse gas emissions, and they continue to increase at current rates, the surface temperature of the Earth can be expected to increase between 0.5 degrees C and 2.0 degrees C (0.9 degrees F and 3.6 degrees F) by 2050 and between 2 degrees and 4.5 degrees C (3.5 degrees and 8 degrees F) by 2100, with carbon dioxide levels over 800 parts per million (ppm). On the other hand, if severe limits on carbon dioxide emissions begin soon, temperatures could rise less than 1.1 degrees C (2 degrees F) by 2100.
Whatever the temperature increase, it will not be uniform around the globe. A rise of 2.8 degrees C (5 degrees F) would result in 0.6 degrees to 1.2 degrees C (1 degree to 2 degrees F) at the equator, but up to 6.7 degrees C (12 degrees F) at the poles. So far, global warming has affected the North Pole more than the South Pole, but temperatures are still increasing at Antarctica.
Effects of Anthropogenic Climate Change
There are a variety of possible and likely effects of climate change on human and natural environments. NASA has tried to list some of those potential effects and can be found here. NASA also has a website called the Climate Time Machine, to help visualize Earth’s key climate indicators and how they are changing over time.
Species Mating and Migration
The timing of events for species is changing. Mating and migrations take place earlier in the spring months, and species that are more mobile are migrating uphill. Some regions that were already marginal for agriculture are no longer farmable because they have become too warm or dry.
Melting Snowpack and Glaciers
Decreased snowpacks, shrinking glaciers, and the earlier arrival of spring will all lessen the amount of water available in some regions of the world, including the western United States and much of Asia. Ice will continue to melt, and sea level is predicted to rise 18 to 97 cm (7 to 38 inches) by 2100. An increase this large will gradually flood coastal regions where about one-third of the world’s population lives, forcing millions of people to move inland.
Glaciers are melting, and vegetation zones are moving uphill. If fossil fuel use exploded in the 1950s, why do these changes begin early in the animation? Does this mean that the climate change we are seeing is caused by natural processes and not by fossil fuel use?
Oceans and Rising Sea Levels
As greenhouse gases increase, changes will be more extreme. Oceans will become slightly more acidic, making it more difficult for creatures with carbonate shells to grow, and that includes coral reefs. A study monitoring ocean acidity in the Pacific Northwest found ocean acidity increasing ten times faster than expected and 10 percent to 20 percent of shellfish (mussels) being replaced by acid-tolerant algae.
Plant and animal species seeking cooler temperatures will need to move poleward 100 to 150 km (60 to 90 miles) or upward 150 m (500 feet) for each 1.0 degrees C (8 degrees F) rise in global temperature. There will be a tremendous loss of biodiversity because forest species cannot migrate that rapidly. Biologists have already documented the extinction of high-altitude species that have nowhere higher to go.
One may notice that the numerical predictions above contain wide ranges. Sea level, for example, is expected to rise somewhere between 18 and 97 centimeters by 2100. The reason for this uncertainty is in part because scientists cannot predict precisely how the Earth will respond to increased levels of greenhouses gases. How quickly greenhouse gases continue to build up in the atmosphere depends in part on the choices we make.
Extreme Weather
Weather will become more extreme with heatwaves and droughts. Some modelers predict that the Midwestern United States will become too dry to support agriculture and that Canada will become the new breadbasket. In all, about 10% to 50% of current cropland worldwide may become unusable if CO2 doubles. There are global monitoring systems to help monitor potential droughts that could turn into famines if they occur in politically and socially unstable regions of the world, and if appropriate action is not taken in time. One example is the Famine Early Warning System Network (FEWS NET), which is a network of social and environmental scientists using geospatial technology to monitor these situations. However, even with proper monitoring, if nations do not act, catastrophes can occur like in Somalia from 2010-2012.
Although scientists do not all agree, hurricanes are likely to become more severe and possibly more frequent. Tropical and subtropical insects will expand their ranges, resulting in the spread of tropical diseases such as malaria, encephalitis, yellow fever, and dengue fever.
An important question people ask is this: Are the increases in global temperature natural? In other words, can natural variations in temperature account for the increase in temperature that we see? The scientific data shows no, natural variations cannot explain the dramatic increase in global temperatures. Changes in the Sun’s irradiance, El Niño and La Niña cycles, natural changes in greenhouse gas, plate tectonics, and the Milankovitch Cycles cannot account for the increase in temperature that has already happened in the past decades.
In December 2013 and April 2014, the Intergovernmental Panel on Climate Change (IPCC) released a series of damaging reports on not only the current scientific knowledge of climate change but also on the vulnerability and impacts to humans and ecosystems. Below are two videos detailing the physical science of climate change and the risks and impacts on the planet.
8.4 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.