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Global Warming: What You Need to Know

© Copyright Oliver Rosengart 2016; cover by Jerry Gonzalez

1

HOW MUCH IS THE EARTH WARMING?

Temperature records have been kept since about 1880, with thermometers located all over the world, so we have a pretty good idea of how much the Earth has warmed since then. The answer is changing almost every year; 2014 was the hottest year ever up to that time, then 2015 was the hottest year, and now, as this is being written, 2016 is almost certain to be the hottest year ever. July and August of 2016 were the hottest months ever.

The answers, depending on which scientists you follow, are between 1 and 1.25 degrees Celsius, 1.8 and 2.25 degrees Fahrenheit since 1880. (2) (see Figure 1) This may not sound like much but keep in mind that this an average temperature for the whole Earth. Also, temperature increases are higher on land than in the oceans; the increase on land can be as much as 6 degrees Celsius, 10 degrees Fahrenheit. The rise in temperature is greater in the Northern Hemisphere where there is more land.

Scientists and responsible world leaders have established a goal of having the Earth’s temperature rise not more than 2 degrees Celsius, 3.6 degrees Fahrenheit. Some have called for limiting the rise to 1.5 degrees Celsius, which we are rapidly approaching, and which is clearly not feasible in view of the changes in behavior that need to be made in order to make that happen.

The other question about the Earth’s warming is: can we measure the Earth’s climate before thermometers were employed? And if so, is the Earth warmer now than it has been in the past? There are several ways that the history of climate can be learned. The ice over Greenland and Antartica is thousands of years old; it snows there but the snow does not melt. There are air bubbles trapped inside the ice and by measuring the concentrations of the different isotopes of oxygen scientists can learn the history of the climate. Sediments in lakes and rings in trees also reveal information about climate history.

The answer is that the Earth is warmer now than it has been for at least 115,000 years; at that time the oceans were between 20 and 30 feet higher than they are today. There is no doubt that the Earth is warming.

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Figure 1 – Temperature anomaly since 1880 (difference between temperature at year indicated and temperature in 1940), showing a rise of slightly over 1 degree Celsius though 2015.

2

Why is the Earth Warming?

The short answer is: the greenhouse effect. Here’s how that works: The Sun’s rays, which include infra red light, are radiated into space and reach the Earth; they pass through our atmosphere and hit the Earth. It is the infra red light, which we cannot see, which warms the planet. The surface of the Earth radiates some of that infra red light, as heat, outward towards space and some of that is captured by the atoms of certain gases. Those gases then reradiate the infra red light as heat back to Earth, warming us.

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Figure 2 – Schematic showing how the greenhouse effect works


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Figure 3 – The concentrations of greenhouse gases.
p<>{color:#fff;background:#298fb5;}. Only certain gases in our atmosphere capture infra red radiation and reradiate it back to Earth. These gases have come to be known as greenhouse gases; they are carbon dioxide (CO~{color:#fff;background:#298fb5;}2~), methane (CH~{color:#fff;background:#298fb5;}4~), and nitrous oxide (N~{color:#fff;background:#298fb5;}2~O). The chart in Figure 3 shows the concentrations of the greenhouse gases in our atmosphere. As you can see, by far the most significant gas is carbon dioxide. However, methane is a more potent greenhouse gas, by some estimates 46 times more potent, and so it is important too.

Oxygen, which exists as O~{color:#fff;background:#298fb5;}2~ in our atmosphere, and nitrogen, which exists as N~{color:#fff;background:#298fb5;}2~, do not trap infra red light and so do not cause us a problem. Molecules with 3 or more atoms are the ones that trap infra red light and reradiate it, and methane, with 5 atoms, is among the worst.

The greenhouse effect is necessary to life on Earth. Without any greenhouse gases reradiating heat back to Earth, the average temperature of our planet would be about 0 degrees Fahrenheit, which is about 60 degrees colder than the present average temperature. This is too cold for liquid water and therefore too cold for life.

The problem is that the amount of greenhouse gases in the atmosphere have been increasing since fossil fuels began being burned.

So what are fossil fuels and how did they come to exist? The period from about 300 to 350 million years ago is called the Carbonaceous Period. The Earth, which looked very different because the continents were not in the same positions that they are in today, was covered with plants. This is long before dinosaurs roamed the Earth. When those plants died they fell to the ground and were eventually buried by other plants, by lava and dust from volcanoes, and by rock that washed off mountains. Over long periods of time that plant material fell deeper into the Earth where heat and pressure cooked it, without access to oxygen, so it did not burn.


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The plant material that was kept dry and heavily compressed for a long time became coal and the plant material that came from swampy areas and was buried with liquids became oil. Other material became gas, which existed mostly in spaces in between rocks. It took tens of millions of years for the plants to grow, die, get compressed and become the coal, oil and gas we take for granted today.

It is only since about about 1750 or so, a blink of an eye in the Earth’s history, that the coal, oil and gas have been taken out of the ground in large quantities. In earlier times wood was burned for heat and for the industrial processes of the day, such as obtaining metals from their ores and fashioning them into useful articles. Burning wood did not increase the carbon dioxide content of the air because the CO~{color:#fff;background:#298fb5;}2~ released by the burning wood was pulled from the air by photosynthesis into the trees; it did not come from under the ground. The carbon dioxide went from the atmosphere into the trees and then back into the atmosphere when the wood was burned.

Then the era of the industrial revolution began and coal became the fuel of choice. The concentration of carbon dioxide in the air in 1750 was about 250 parts per million (ppm). This has been accurately measured in bubbles in ice cores taken from the Greenland and Antartica ice sheets.

As the industrial revolution continued into modern times, and as the Earth’s population grew from about 700 million in 1750 to over 7 billion today, oil and gas joined coal in fueling our lives. More and more carbon, as carbon dioxide, went from under the ground into the atmosphere until today the concentration is just over 400 parts per million. The concentration is increasing at the rate of over 2 parts per million per year, and the rate of increase is itself increasing. A goal of some climate scientists is to limit the concentration of CO~{color:#fff;background:#298fb5;}2~ to 500 ppm, which means drastically changing our ways, and that level would be reached in less than 50 years. It is believed that 500 ppm would mean a warming of about 2 degrees Celsius.

 

 


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So the Earth is warming year by year due to the increase in the concentration of greenhouse gases, mainly carbon dioxide, in the atmosphere that comes mostly from the human activity of burning fossil fuels. Figures 4 and 5 show how the warming of the Earth is very directly related to the amount of carbon dioxide in the atmosphere. Figure 4 goes back about 1000 years, and Figure 5 goes back to about 1880.

Methane (CH~{color:#fff;background:#298fb5;}4~), a very potent greenhouse gas, is also exacerbating the problem. It comes partly from gases produced by cows as they digest the grasses they eat. One of the many steps that can be taken to combat global warming is to reduce the amount of beef consumed by the world.

Another source of methane is the melting of the permafrost in the arctic. Plants that lived and died much more recently that those described above became buried just below the surface of the Earth in the arctic. They froze and became what is called permafrost, because they never melted. Until now, when they are beginning to melt. The permafrost extends an average of about 12 feet below the Earth’s surface and covers a vast area in Northern Canada, Russia and Scandinavia. Scientists believe that an enormous amount of methane is trapped in the permafrost and its release into the atmosphere will significantly exacerbate global warming. It would cause the 2 degree threshold to be reached earlier than 50 years from now; how much earlier, no one knows.

Methane is found in the earth and it is used as a fossil fuel; more on this later. Another source of methane in the atmosphere is leakage from the mining process. The industry claims that very little leakage occurs; many climate scientists disagree and say that the leakage is another reason that the Earth is warming.

There is enormous variation from country to country in the amount of emissions that contribute to global warming. The term used to describe how much we emit is “carbon footprint”. The U.S. and China are the worst, with the largest carbon footprints. We contribute more than 25% of the world’s emissions, even though we have only 4.35% of the world’s population. China is about equally bad, but of course it has more than 4 times as many people, and it has a history of being very poor until relatively recently. India, with about one sixth of the world’s population, is also a serious polluter.

Underdeveloped nations, such as several in sub-saharan Africa, have very small carbon footprints. More than one billion people in the world do not have access to electricity, many do not have cars, and many have no need for home heating since they live in a warm climate. In Myanmar, for example, a country just east of India, more than 75% of the population has no electricity. Some countries’ footprints’ are under 1%.

Some other countries have small carbon footprints because they have non-fossil fuel based energy sources. France gets 75% of its electricity from nuclear power; Brazil has a highly developed hydroelectric power system and uses biomass to power automobiles (more on this later). Europe as a whole uses about half as much fossil fuel per capita as the United States, partly because their public transportation systems are better and partly because they charge much more for gasoline so people use less.

The part of the world that is experiencing warming the most is the arctic, where the sea ice is melting. Each year the amount of ice in the summer is less than the previous year. This exacerbates global warming because the whiteness of ice is very reflective, which lessens the warming process, and so less ice means less reflection of the sun’s rays. The reflectivity of the Earth is called its albedo.

A more obscure, but very important cause of global warming is a group of chemicals called hydrofluorocarbons (HFC’s for short). These are chemicals that are used in air conditioners and refrigerators. They replaced chlorofluorocarbons (CFC’s), which were banned by a worldwide treaty in 1987, because CFC’s removed ozone from the atmosphere. Ozone blocks ultra violet light from reaching the Earth and the increase in UV light causes cancer and a decrease in plankton.

Although there is not much HFC in the atmosphere, its importance lies in the fact that it is 1,000 more potent than carbon dioxide in acting as a heat trapping greenhouse gas.

The good news is that on October 14, 2016 170 nations reached agreement to phase out HFC’s. The agreement is in the form of an amendment to the 1987 treaty on CFC’s and so it has the force of law. The HFC agreement means that all countries signing on are legally obligated to comply and will face sanctions for their failure to do so. The phaseout is over time, with richer countries reducing their use sooner and poorer countries later.

This is enormously important. Scientists estimate that phasing out CFC’s is equivalent to the reduction of the equivalent of 70 billion tons of carbon dioxide from the atmosphere — about two times the carbon pollution produced annually by the entire world. In terms of temperature reduction, it is estimated to prevent 1 degree Fahrenheit of warming.

The compulsory aspect of the HFC agreement is unlike the Paris Accord of December, 2015, which provides for voluntary, non-binding efforts to reduce emissions. The goal of the Paris Accord is to limit global warming to 2 degrees Centigrade, and to pursue efforts to limit the warming to 1.5 degrees C. The latter goal is obviously impossible to reach since the world is already close to that level of warming. This far 192 countries have signed on. It is the world’s first comprehensive climate agreement.

Deforestation, the wholesale cutting down of trees in order to obtain land suitable for crops, is another significant cause of global warming. More on that in the next chapter.

So the answer to the question raised in the beginning of this chapter is that the Earth is warming for several reasons, by far the most significant one being the release of carbon dioxide into the atmosphere caused by the burning of fossil fuels.

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Figure 4 – Graph showing that the temperature varies with the amount of carbon dioxide in the air, from 1000 C.E. (Common Era) to the present. The blue line is carbon dioxide concentration.
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Figure 5 – Graph showing the relationship of temperature to carbon dioxide content of the atmosphere since 1880. The red line is carbon dioxide concentration.
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3

The Effects of Global Warming

Spoiler alert: this is a depressing chapter. But there is cause for optimism later on.

The problem with predicting the effects of global warming is that the phenomena of warming caused by increased carbon dioxide in the atmosphere has never happened before in human history. So there is little to go on in making predictions. Also, no one knows when the world will wake up and reduce carbon dioxide emissions and so no one knows what the future concentration of greenhouse gases will be and therefore what the temperature will be then. Lastly, there are major unknowns, such as the amount of methane that will be released by the melting of the permafrost. Some of the effects are depicted in Figures 6 and 7.

A – The Oceans

When the temperature of almost any object increases, the molecules that make up that object move faster, bump against each other more strongly, and the object increases in size. This is exactly what has happened to the oceans. The increase in the temperature of the Earth has caused the oceans to expand, resulting in a measurable increase in the level of the oceans in relation to the land. In the last 50 years the oceans have risen about 8 inches, but this varies with local conditions. In Los Angeles the rise was only 2.5 inches, while in Galveston, Texas it was 12.5 inches.

This means that when there is a storm surge the flooding of coastal areas will be much more severe. Pacific Island nations are the most vulnerable. As the oceans rise many will simply disappear. The Marshall Islands, with 70,000 inhabitants is among those places.

An Alaskan village named Shishmaref, on a barrier island, recently voted to relocate their village to higher ground. Twelve other villages in Alaska also decided to relocate; 19 others, which have not yet decided what to do, are threatened by rising waters. These villages have been inhabited for over 400 years.

The federal government recently relocated the entire town of Isle de Jean Charles, Louisiana.

Bangladesh is the most worrisome. It is very densely populated, very poor and flat. The country’s climate scientists predict that by 2050 rising sea levels will inundate 17 percent of the land and displace 18 million people. Bangladesh is underdeveloped and so has contributed almost nothing to the problem of global emissions. Their leaders have demanded that the polluting nations compensate Bangladeshis, even by allowing them to move to the United States.

Worldwide as many as 200 million people could be displaced by rising seas by 2050, according to a study for the British government.

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Figure 6 – Some effects of Global Warming
p<>{color:#fff;background:#298fb5;}. No one really knows what the future brings. Predictions of sea level rise range from a low of 2.5 feet to as much as 80 feet. The reason the predictions are so varied is that there are major unknowns: the ice sheet covering a large part of Greenland is melting rapidly and may slide suddenly into the ocean, and a huge block of ice in West Antartica, also melting rapidly, may fall into the ocean. The worst case scenario will cause major tsunamis and will make coastal cities and areas all over the world uninhabitable. The estimates of the number of people whose homes would be lost due to such ocean rise ranges from 200 million to one billion. When such great numbers of people are forced to move inland, to land that is already inhabited, the results are almost too horrible to contemplate: homelessness, famine and starvation, warfare, tens or hundreds of millions of deaths. Nothing like this has ever happened before in human history so it is impossible to make even remotely accurate predictions.

Glaciers are melting all over the Earth, which is also making the level of the oceans rise. Glacier National Park in Idaho is forecast to be without glaciers by 2030. In Alaska there are glaciers that are moving faster than ever, with large chunks of ice falling into the oceans. The arctic ice shrinks every year and it is forecast that within the next few years there will be no arctic ice in summer.

Counterintuitively, this melting does not raise the level of the oceans since Arctic ice is already floating. You can observe this by putting ice cubes in water and you will see that when the ice melts the water level does not rise. The disappearance of the ice, however, is causing the death of seals, which need the ice for birthing and for protection. It is also leading to the possible extinction of polar bears which depend on the ice to catch seals to eat.

The other major calamity that is happening to the oceans is that they are becoming more acidic. When carbon dioxide dissolves in water carbonic acid is formed; the chemical reaction is CO~{color:#fff;background:#298fb5;}2~ + H~{color:#fff;background:#298fb5;}2~0 == H~{color:#fff;background:#298fb5;}2CO{color:#fff;background:#298fb5;}3~. This has caused coral reefs all over the world to blanch (whiten) and portions of them to die. About one quarter of world’s fish use the coral reefs as spawning grounds and without the coral reefs they will die off. Over one billion people depend on fish from coral reefs for protein.

The ocean currents, which bring warmth from the tropics to Northern areas, may be disrupted by global warming. This has not happened yet but scientists believe that it is a possibility. The Gulf Stream warms Northern Europe and if it ceases to run or is diverted, Northern Europe will become very cold and will not be able to support the agriculture that is necessary to feed its people. Some areas will become surrounded by ice and since they depend on ocean shipping and fishing for survival, they will become uninhabitable. Iceland is particularly threatened by this possibility.

Some populations of fish have been moving North to escape the warming seas, which disrupts fisheries. Lobsters that were caught for many years off the coast of Massachusetts are now found off the coast of Maine.

B – On Land

There are many effects of global warming, and more are discovered all the time. Only a portion of them can be addressed here. As with the oceans, the effects on land depend on when greenhouse gas emissions are reduced to the level that the Earth can absorb.

Global warming causes more water to be evaporated from the oceans and therefore more rain is falling worldwide. In some areas this is causing extensive flooding. In 2015 there was flooding in England, at levels that were not expected to happen more often than every 200 years. This is just one example of flooding; floods are happening all over the world to an extent never before seen in recorded history.

At the same time, weather patterns are changing and other areas are affected by severe droughts. This is happening in the Southwestern United States, in Sub-Saharan Africa and China. Some formerly arable land is becoming desert, permanently; this is called desertification.

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Figure 7 – Some effects of global warming on agriculture and on land.
p<>{color:#fff;background:#298fb5;}. Both floods and droughts make farming impossible and scientists fear that, with the Earth’s population expected to reach 9 billion by the end of the 21st century, there will be famines.

Lake Poopo was once Bolivia’s second largest lake. Many Uru-Murato people lived off its waters for generations but now it is a dry, salty expanse. The fish died, the birds that ate the fish left, and most of the people who lived there also left.

As some forests have become dryer the intensity and number of forest fires in the West has increased enormously. A recent study estimated that since 1984 climate change has caused an increase in areas burned equal to 16,000 square miles, the size of Massachusetts and Connecticut combined. (11)

In the history of the Earth there have always been extinctions. It has been estimated that 99% of the species that have lived on our planet since it formed 4.5 billion years ago have become extinct. However, extinctions are occurring now at a much faster rate than ever before.

This affects both plants and animals. An Australian rodent, the Bramble Cay melody, a mammal, recently became extinct due entirely to human driven climate change.

To escape the warmer climate many animals and birds are moving North and up to higher elevations on mountains, but those that cannot adapt will become extinct. Of course there are many plants that cannot move. The only question is what portion of the world’s plants and animals will go extinct. Estimates run to 20% and higher.

What does this mean for humanity? In addition to a world that is less diverse and less interesting, many medicines come from plants. Some doctors have already expressed the view that as antibiotics lose their effectiveness due to overuse and the evolution of viruses, humanity will have to turn more to naturally occurring substances. Extinctions caused by global warming will make such substances scarcer.

Although this is not yet happening, there is a fear that tropical diseases, such as malaria, will move north. Since there are already about one million deaths annually from malaria, this could be a serious problem. Studies have shown that some tropical insects have moved north and so it is likely that some tropical diseases will be spread by those insects. (13)

Hurricanes, tornadoes, cyclones and other severe weather phenomena have already become worse and will become even more damaging in the future. The flooding, deaths, and billions of dollars in property damage have already been experienced in the United States. Hurricane Katrina killed over 1,000 people and caused an estimated $125 billion in damages and Hurricane Sandy (which was a tropical storm by the time it reached land) is estimated to have caused $75 billion in damages. These storms are spawned over the ocean and there is no doubt that global warming makes them worse.

So what can we conclude about the effects of global warming? In the best case scenario, with global warming limited to two degrees Celsius, we will experience more of what we are presently experiencing: more extinctions, more intense storms, worse droughts, worse flooding, declines in fisheries, loss of coastal land due to rising oceans, all of the above to unknown extents.

In the worst case scenario, with no action being taken to combat global warming, with temperatures rising 4 degrees Celsius, 7 degrees Fahrenheit and more, the consequences for humanity are unimaginably terrible: massive loss of land due to ocean levels rising, huge coastal areas including many heavily populated cities becoming uninhabitable, terrible famines, warfare between groups competing for habitable and arable land, diseases that overwhelm healthcare systems, extremely severe storms, huge numbers of homelessness and deaths, and consequences that we cannot even contemplate.

4

Deforestation and Reforestation

Forests play a very significant role in keeping carbon dioxide out of the atmosphere. Scientists say that between 20 and 25 percent of the world’s carbon dioxide emissions are absorbed by forests. (14) Trees pull carbon dioxide out of the air as they grow taller and wider, and as they grow leaves each year, and that carbon dioxide gets locked into their wood and, and into the soil beneath the trees.

Deforestation, the removal of trees in order to use the land for other purposes, is a significant cause of global warming. At least three quarters of the world’s pre-industrial forests have been cut down. The motivation for deforestation is mostly agricultural, both for subsistence farming and also for large agribusiness farming and cattle raising. Forests are also cut down for urban development and for wood. It is estimated that 3 billion people still depend on wood for heat and cooking. Wood is also harvested for charcoal and construction. Most deforestation today takes place in underdeveloped countries.

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Figure 8 – The causes of deforestation
p<>{color:#fff;background:#298fb5;}. Other harmful effects of deforestation include soil erosion, occasionally leading to desertification, and loss of biodiversity.

The good news is that there have been successful movements in some countries to limit deforestation and even to plant new trees, called reforestation. The biggest success story is Costa

Rica. In the middle of the 20th century a majority of its old growth forests were cut down but since then there has been a huge effort made to conserve what remained and to plant new trees that now more than half of the country is forest. (14) This was easier to accomplish than than in more densely populated countries; the population is only about 4.8 million.

Brazil presents another cause for optimism. Most of the amazon jungle is in Brazil and for years deforestation was rampant; Brazil led the world in deforestation. After valuable trees were cut down and taken away the remainder were burned, releasing huge amounts of carbon dioxide into the air and creating smoke which was visible in space. Brazil has recently begun to reverse that process, both by aggressively enforcing laws against deforestation, and by starting a massive program of reforestation. The future of these efforts is fragile, however, with changes in the government and with difficulties in enforcing laws in remote areas of the jungle.

The other side of the coin is in Indonesia, which now leads the world in the rate of deforestation. Huge fires in Indonesia have also been seen in space. The government declared a moratorium on new logging permits but this was ineffective and the rate of deforestation increased.

Reforestation on a world wide scale has the potential to significantly reduce global warming. The problem is that economic progress in underdeveloped countries, together with population increases, leads to pressure to increase areas in which crops are grown and cattle are fed.

5

How We Use Energy

In our daily lives most of us have very little awareness of how we use energy. Figure 9 gives a rough breakdown of the ways we use energy.

The food we eat uses energy, 14% of the total. It starts with the farm machinery, tractors, harvesters, pumps for irrigation and spraying water, airplane fuel for spreading insecticide; etc. Then there is the fuel consumed in transporting food to the marketplace, including FreshDirect trucks bringing food to customers’ homes. A substantial amount of food is now flown long distances, such as fruits and vegetables from Latin America in our winter time, and flying uses a great of fuel. Then there is electricity used to refrigerate the food in stores, and to light the stores. Lastly, of course, energy is used to cool food in our refrigerators and to cook, and then to heat water to wash dishes and to make electricity to run dishwashers. .

Home heating and cooling uses 17% of the total amount of energy we use. Homes, including apartment buildings, are heated with oil or gas. Until the 40’s and 50’s many apartment buildings were heated with coal. They were first converted to oil and later many were again converted to systems that could burn gas, or both gas and oil. Most heating systems in apartment buildings are in the basements and produce steam which is piped all around the building to radiators in apartments. Such buildings are often overheated and wasteful of fuel. Many modern buildings have individual, gas fired, heating units in each apartment, with the heat being distributed around the apartment by pipes carrying hot water. Such systems have thermostats that can regulate the temperature in the apartment and are considerably less wasteful of fuel.

Home cooling is often from electrically operated window air conditioners, which have compressors that use a lot of electricity. Large, modern buildings have central air conditioners which use pumps to move cooled water around a building; these use less electricity but still a lot. Homeowners often have very large electric bills in the summertime.

The amount of energy expended for heating and cooling is very dependent on location. Obviously, buildings and houses in Southern climates use less energy for heating and more energy for cooling that those in Northern climates, and vice versa.

Apartment dwellers in cities use much less energy for home heating and cooling because most apartments have only one or two walls that are exposed to outside air temperatures, with the other walls being effectively insulated from the outside air by other apartments. Also, apartment dwellers obviously have less space to heat and cool than owners of one or two family homes.

Other home energy usage accounts for 15% of the total energy used. This consists of electricity used for lighting, refrigerators, appliances such as toasters, dishwashers, washing machines, computers, televisions, radios, etc. Added to this would be hallway lighting and elevator usage in apartment buildings.

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Figure 9 – How we use energy
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Stuff you buy; 26% of the total. All the clothing you wear is made on electrically powered looms. In former times many clothing factories had looms powered by moving water with no fossil fuels involved. Practically everything we buy is made in factories powered by electricity; books, smart phones, furniture, cars, paper (from trees cut down with chain saws powered by gasoline), the keys in our pockets, pens and pencils, cups and plates that hold food, and so on. As one goes through the ordinary activities of the day, almost everything we touch and use has consumed energy, which we do not think about.

Lastly, there is transportation, consuming 26% of the energy we use. There is gasoline for cars; diesel fuel for trucks, buses, trains and some cars; heavy oil and diesel fuel for ships; and kerosene for jet planes (all of which come from oil). Jet planes, as you might expect, use enormous amounts of fuel; it takes a lot of energy to keep so much weight in the sky, moving at 500 or so miles per hour. There is electricity for subways and commuter trains. The less obvious include electricity for escalators, elevators and lighting in the subway system, electricity for electric cars (still rare but growing in number), and electricity for some buses.

 

6

Where Our Energy Comes From

This pie chart shows the various sources of energy in the United States, and the percentage of each, as of 2011:

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Figure 10 – Where our energy comes from.
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The bad news is that the first three, petroleum, gas and coal, are the ones that come from fossil fuels and therefore the ones that are increasing the carbon dioxide content of the air, and they constitute 81% of the total source of our energy as of 2011.

As you can see from the above table, non-polluting, renewable sources of energy, including nuclear power, only amount to slightly under 20% of our energy. However, some of them are growing rapidly; wind increased by 5% and solar by 30% in one year. The costs of the latter sources are now competitive with fossil fuels in some areas and the forecast is that their cost will continue to decline and their share of the source of energy will increase rapidly in the next few years. This depends as much on political will as on cost.

The goal of the environmental movement is to substantially change these percentages, to the point where the concentration of carbon dioxide in the air stops rising, and the warming of the Earth is limited to 2 degrees Celsius. In order for that to happen people need to understand the issues, which is the goal of this book. Each source of energy is examined in more detail below.

 

7

How Electricity is Made

In order to change the way we use energy, we must first understand the details of how we use energy. We will start with how electricity is made.

Between 1821 and 1831 Michael Faraday, a British scientist, developed the theories that led to the production of electricity. In a nutshell, he discovered that electricity is made when a wire passes through a magnetic field. This is how a generator in an electric power plant works. An electric motor works the opposite way: passing an electric current through wires in a magnetic field will cause the wires, when they are mounted on something that has the ability to turn, to rotate. This is worth repeating: electricity is produced when a wire passes through a magnetic field. This applies to all the methods of producing electricity except solar panels.

Figure 11 is a schematic drawing of a generator, and Figure 12 is a photograph of a commercial utility company generator. There is a stator which, as its name implies, remains stationary. The stator is a magnet. The rotor is turned by a power source so that the wires that make up the rotor pass through the magnetic field, causing an electric current to flow though the wire. It is the turning of the rotor that involves the input of energy.

So what makes the rotor turn? As shown in the schematic in Figure 13, a source of heat from the combustion of coal, oil or gas, boils water which makes steam. The heat source can also be from nuclear fission (more on this below). The steam hits the blades of a turbine, causing it to turn, much like wind causes a windmill to turn. This causes the rotor to turn, pushing wires through a magnetic field and generating electricity which is carried by wires to homes, businesses and everywhere else that electricity is consumed.

There is, of course, a lot of complicated science and engineering involved in this process. The electricity is first produced as direct current and then converted to alternating current, which is better for transmission over long distances. The voltage is stepped up to a very high level for transmission (so that less of it will be lost) and then stepped down with transformers for use by consumers. The details of this is the work of electrical engineers and is beyond the scope of this course.

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Figure 11 – Schematic drawing showing how a generator works. The wire, the red and blue, is turned through the magnetic field, generating electricity.
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Figure 12 – Schematic showing how a commercial electrical generating plant works.
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Figure 13 – Photograph of the inside of a commercial generator.
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8

Coal

As mentioned above in Chapter 2, the Carboniferous Period, about 300 – 350 million ago was characterized by a great deal of swamp lands and thick plant life. As the plants died and sunk to the bottom of the swamps, they were buried by water and marine sediments and by rocks that eroded into the water. As this material sunk deeper into the Earth it was heated under pressure for millions of years, and became the coal we know today.

Coal exists in several different forms, depending on how long and how deeply it has been buried and how much heat and pressure cooked it. Material that recently died and is near the surface is called peat, which is used as a fuel in some countries. Bituminous coal is denser than peat but the most dense, and therefore the most valuable as a fuel, is anthracite coal.

Coal is mined both on the surface and underground. On the surface it is called strip mining. This involves removing large amounts of non-coal earth that covers the coal, then digging up the coal with enormous powerful shovels, transporting it by truck to trains, and then taking it to electrical power plants by 100 car long trains. A typical coal fired plant uses about two 100 car long trains full of coal every week! (Figure 14) (15) As you can imagine, surface (strip) mining does a lot of environmental damage.

Underground mining takes place at depths usually less than 1,000 feet, but occasionally deeper. In modern times in the United States it is largely automated, but the coal dust caused by the machinery is still very dangerous to the miners.

Coal is the most polluting energy source, for many reasons. Coal is almost entirely carbon and so when it is burned only carbon dioxide is produced. C + O~{color:#fff;background:#298fb5;}2~ CO~{color:#fff;background:#298fb5;}2~. A typical coal fired electrical generating plant produces a staggering amount of carbon dioxide, about 1,000 tons (two million pounds) per hour! Other fossil fuels produce less CO~{color:#fff;background:#298fb5;}2~ for each unit of heat produced. Gas is mostly methane, whose formula is CH~{color:#fff;background:#298fb5;}4~. When it is burned carbon dioxide and water are produced: CH~{color:#fff;background:#298fb5;}4~ + 2O~{color:#fff;background:#298fb5;}2~ === CO~{color:#fff;background:#298fb5;}2~ + 2H~{color:#fff;background:#298fb5;}2~O. Although it may seem counterintuitive that the formation of water by combustion of hydrogen produces heat, it does so, and the emission of water is not harmful to the environment.

Coal also contains sulfur dioxide, SO~{color:#fff;background:#298fb5;}2~, which combines with water in the air to form sulfuric acid: SO~{color:#fff;background:#298fb5;}2~ + 2H~{color:#fff;background:#298fb5;}2~O H~{color:#fff;background:#298fb5;}2SO{color:#fff;background:#298fb5;}4~. This falls to earth as acid rain, which kills fish in rivers and lakes.

Coal contains mercury, a heavy metal that is very unhealthy.

Lastly, the fine particulates that come from burning coal are very unhealthy. It has been estimated that the use of coal causes about 24,000 deaths a year in the United States alone, and 366,000 deaths per year in China. Some politicians have referred to coal as a clean energy source, which is absurd.

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Figure 14 – Train carrying coal, typically about 100 car lengths long, more than 3 times as long as shown. A typical coal fired electrical generating plant uses two trainloads per week.
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Coal can be processed into a gas or a liquid. Before electricity was available for electric lights, coal gas was piped to homes and used for illumination. As a liquid coal can be used in the same way gasoline is used to power automobiles. Both of these processes increase the cost of fuel substantially and do not reduce the carbon footprint of coal.

The good news is that use of coal has been declining rapidly in the United States since about 2009. This is primarily due to market forces in that gas, from shale and fracking (more on this later), has become available at low prices. The percentage of coal as a source of energy in the U.S. declined 12.66% in one year, from 2014 to 2015. Many coal producing companies are having trouble surviving economically. There have been reports that banks are refusing to lend to coal companies because the banks believe that the coal companies may be out of business soon.

The Obama administration enacted a regulation that would have required coal fired electricity generating plants to sharply reduce their emissions of carbon dioxide, which would have forced many of them to close. However, the industry and Republican legislators sued and a court has, for the time being, suspended enforcement of that regulation. This may change in the future

Figure 15 shows coal production in the five most coal producing countries of the world. Obviously China is the main offender. China’s reaction to criticism over its coal use is that it is necessary because it is an underdeveloped country and it needs to use coal to catch up to the developed countries. However, there have been protests by the people of China over the terrible air pollution caused by coal. China’s coal use has prompted some conservatives in the United States to say that we should not do anything to combat global warming since whatever we do will be undone by China, and will make us less competitive in world markets.

The good news from China is that it recently announced that it would take aggressive steps to develop alternate sources of energy. However, this will take time and in the interim China’s carbon footprint in very high, similar to ours.

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Figure 15 – Coal production in the world as of 2010.
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9

Petroleum

Petroleum, or oil, is a fossil fuel which is formed when large quantities of dead zooplankton and algae are buried underneath sedimentary rock and subjected to intense heat and pressure for millions of years. Zooplankton are mostly very small animals, of which jellyfish is a larger version, which float in the ocean. When they die they sink to the bottom of the ocean. The sedimentary rock which covers them comes from rock which is washed off mountains by wind and rain over millions of years.

Oil is obtained by drilling into the earth. If the oil is sufficiently under pressure, it comes to the surface by itself. After the pressure goes down the oil is pumped out of the earth as crude oil. Crude oil is a mixture of several different kinds of hydrocarbons, chemicals that contain carbon, hydrogen and oxygen. They are separated from each other in refineries, some of which are in New Jersey and are visible from the turnpike. The components of petroleum range from light products including gasoline and kerosene to much heavier ones such as asphalt and tar. Many other chemicals come from petroleum and are used to make plastics, pharmaceuticals and many other materials.

Unlike coal, which scientists say can last as much as hundreds of years before it is used up, oil reserves in the ground are limited. BP, a major producer of gasoline, estimates that the presently known reserves of oil give us only about 50 years before oil is virtually gone. There are other estimates that are even lower, but some scientists say that more will be discovered during this time so it will last longer. Of course these estimates are based on current rates of usage, which could decline as alternate fuels are developed, although they also could increase as the world’s population increases. One thing is clear: at some point during this century oil will become much scarcer and much more expensive.

Internal combustion engines and jet engines are, of course, the means by which cars, trucks, buses, some trains, and airplanes are powered. The details of how they work is beyond the scope of this course but much information on this topic is available on Wikipedia. As they are presently operated they all require a liquid fuel. That is what makes oil so important. In the previous chapter on coal it is stated that coal can be converted to a liquid form, but this is expensive and coal would still be very polluting, more than oil, in its carbon dioxide output. Very little oil is used for the production of electricity.

As the reserves of oil run low there will almost certainly be other forms of liquid fuel developed. This is already happening. More on this below.

10

Natural Gas

Natural gas, or simply gas, not to be confused with gasoline, is a fossil fuel which, like coal and oil, was produced millions of years ago when plant and animal material was buried under intense heat and pressure. It consists mostly of methane, CH~{color:#fff;background:#298fb5;}4~, but also contains ethane, propane, butane, and pentane, which have 2, 3, 4 and 5 carbon atoms respectively, along with proportionately larger amounts of hydrogen.

It is found in several different ways: in pockets by itself in bogs and marshes near the surface, in pockets near the surface along with coal and oil deposits, and deeper underground in shale.

Known reserves of natural gas at the present rate of usage are estimated to last up to 250 years; if the rate of usage increases at the rate of 2-3% per year the reserves may last only 80 - 100 years.

It is shale gas that is plentiful and a cause of controversy.

Shale is a kind of rock. Natural gas is contained in tiny spaces in the shale and the gas will not flow out of the rock when a pipe is simply put into it. This is in contrast to deposits near the surface which accompany oil and coal deposits where the gas flows on its own when piped. For the gas in shale to be released it needs to have a pipe put into the shale horizontally, or nearly horizontally, as in Figure 16. Enormous quantities of water under very high pressure, along with some sand and many chemicals, are pumped into the pipe, which fractures the shale rock. The pressure is then released, the water pumped out, and then natural gas flows freely. The water is disposed of by being pumped back into the ground. There are over one million such wells in the United States, 2.5 million worldwide.

This is a process called fracking, hydrofracking or hydraulic fracturing, and it is very controversial. Proponents point out, correctly, that it has led to the United States becoming self sufficient in oil (since much of the oil formerly used for heating has been replaced by natural gas), and the cost of heating has declined as a result. Natural gas is also used for the production of electricity and it presently produces electricity at the lowest cost. Proponents also point out that it is less environmentally harmful than coal since the combustion of natural gas produces both carbon dioxide and water whereas coal produces almost entirely CO~{color:#fff;background:#298fb5;}2~. Since it is more environmentally friendly than coal, it has been termed a transition fuel, that is a fuel that will serve as the transition to renewable, non-polluting sources.

The critics of fracking point out, also correctly, that since an average fracking well uses about one million gallons of water, this will exacerbate already existing water shortages. Also, fracking pumps significant quantities of chemicals, an average of about 50,000 gallons, into each well. Fracking companies are permitted to not disclose the composition of the chemicals pumped on the grounds that these are trade secrets, which prevents scientists from evaluating the safety of these chemicals. The long term effects on drinking water are not yet known, although there have been reliable reports of some sources of drinking water that have become polluted and undrinkable. There is a report from Pennsylvania of well water that was able to be put on fire as a result of fracking.

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Figure 16 – How Gas is Obtained From Fracking. Water and chemicals are pumped under pressure into the pipe, fracturing the shale and releasing gas.
p<>{color:#fff;background:#298fb5;}. In addition to water shortages and pollution, fracking is known to cause earthquakes. Oklahoma went from having about 2 earthquakes a year to having 585 earthquakes above 3.0 on the Richter scale in 2014. Texas has also seen a significant rise in earthquakes. Oklahoma now exceeds California in its number of earthquakes. Whether fracking will cause earthquakes that lead to loss of life and significant property destruction is unknown. New York and many other states and localities have banned fracking; there are ongoing legislative battles on this issue.

 

11

Saving Energy

I promised you in the chapter on the effects of global warming that there would be more optimistic chapters later on. Here is the first: how energy consumption can be reduced.

Figure 17 shows many of the ways. There are three broad categories of ways to save: consume less electricity, consume less fuel, consume fewer goods.

There are so many ways to reduce electricity consumption. There’s the obvious: turning off lights when they are not needed. Using LED (Light Emitting Diode) bulbs, which use about 10% as much electricity as ordinary incandescent bulbs. Using appliances that are rated to be energy efficient. Running dishwashers and washing machines only when they are full. Unplugging appliances, such as toasters, when they are not in use. Using a clothes line instead of a dryer.

There are other less obvious ways to reduce electricity consumption. Get escalators to work only when someone is riding on them; escalators that work only when someone steps on a pedal already exist. Press legislators and regulatory agencies to require that lights in office buildings be turned off when not in use. Have lights in hallways operated with motion detectors, a readily available technology, so that they are on only when someone is in the hallway instead of all the time. Pass laws that stores that are air conditioned cannot leave their doors open. Require doors on refrigerators in supermarkets (at present only frozen food refrigerators have doors in many stores). Turn up the temperature on air conditioner thermostats a couple of degrees.

There are consulting firms that advise businesses on how they can save energy costs, and there are plenty of employment opportunities in this field. This list could go on for several pages; I am sure readers of this book could think of many more ways to reduce electricity consumption.

Liquid fuel consumption also needs to be substantially reduced. In homes and apartment buildings insulation is a key factor. There are still old houses and apartment buildings without any insulation in the walls and roofs. There are technologies available to blow insulation into wall cavities, and new homes and large buildings are being built with more and better insulation. Many buildings are overheated. Antiquated, fuel inefficient heating systems can be replaced and the new system will be paid for in lower fuel costs. Thermostats can be turned down slightly without residents being inconvenienced; in many private homes, where people are conscious of their fuel consumption, some people simply wear sweaters. Thermostats can also be lowered in hot water heaters; they are generally set at a temperature so high that cold water needs to be added to make the hot water useable for washing.

Then there is fuel consumed by cars, trucks and buses. A lot has been done to improve fuel efficiency in vehicles in the last 50 years. A car I owned in 1959 got 10 miles to the gallon.

The Obama Administration enacted regulations mandating that vehicles achieve an average of 54.5 miles per gallon by 2025, about double the present average.

This has been supported by the major automobile manufacturers and by the Transport Workers Union, so it appears likely to be achieved. It means the development of smaller, more efficient engines, lighter car bodies (more plastic, less steel), development of better fully electric vehicles and hybrids which use both gas and electricity (both of which already exist), and research and possible development of vehicles which run on natural gas.

All is not rosy in the field of energy reduction. The world’s population, now at 7.3 billion, is estimated to increase to 9.7 billion by 2050 and 11.2 billion by 2100. When I was a child in the 1950’s it was 3 billion. Also, as underdeveloped countries develop, their consumption of energy rises considerably. Both of these factors offset reductions of emissions achieved by energy saving measures. To what extent no one knows.

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Figure 17 – Some Ways to Save Energy.

12

Solar Panels

We turn now to the last part of this book: alternative sources of energy. They are solar panels; wind turbines; nuclear energy; hydroelectric power; biomass; geothermal power, and tidal power. They are sometimes referred to as renewable sources of energy, as opposed to fossil fuels which are not renewable. None of these emit carbon dioxide (except biomass; more on that when we get to it) and so they are the means by which global warming can be stopped. However, they all have drawbacks.

I mentioned earlier that they way electricity is produced is by pushing wires through an electric field. That is true for all sources of electricity except solar panels. Here is how solar panels are made and how they work.

A solar panel is made mostly from silicon, an element which comes from sand so it is essentially unlimited in its availability. The silicon in the sand is melted so it can be poured into a thin layer. In order to get the silicon layers to generate electricity two different kinds of silicon layers are made: one contains a small amount of boron and becomes positively charged and the other contains a small amount of phosphorous and becomes negatively charged. The layers are placed one on top of the other and a wire is attached. The wire becomes part of a circuit or loop that ends up at another end of the wafers. A somewhat oversimplified way it works is: when a photon of light from the sun hits the negatively charged layer it knocks an electron loose and the electron flows to the positively charged wafer. This is the essence of what is called the photoelectric effect, which was discovered by Albert Einstein in 1905. The layers are then unequal in their electrical charge and this causes a current, consisting of electrons to flow. This is illustrated in Figure 17. Research is ongoing regarding the use of other materials in the silicon to improve efficiency.

There is an obvious drawback to solar panels: they only work when light hits them. Since they do not function at night they are much less useful in far northern latitudes where nights are very long for much of the year. They are also less useful in cloudy or rainy areas such as the Pacific Northwest. In areas where there are lots of shadows, such as forests and cities where tall buildings cast shadows on shorter buildings, they are also not suitable.

Another drawback is that they cover a lot of area, which means they are less desirable on land that can be farmed and in densely populated areas where existing vacant land can be developed for for residential use. See Figure 18. The most desirable places for solar panels is in deserts.


***

The cost per kilowatt hour of electricity produced by solar panels varies greatly, depending on the area in which the panels are located. The more electricity produced, the lower the cost per unit. At the present time the cost per kilowatt hour of electricity from solar panels in many areas is equal to or less than the cost of electricity produced by utility companies using coal. And the cost keeps dropping; it fell by 60% from 2011 to 2014 and it is predicted to fall another one third or more in the next three years. This is one of the reasons coal companies are in trouble.

There is much cause for optimism regarding solar power. Hillary Clinton’s proposal was to install half a billion solar panels, which would have made the cost fall even further. Trump has said he supports the use of coal but the economics of these positions may have more of an effect than the politics. The price of coal, due to its environmental costs, will rise and the price of solar power keeps falling.

China recently announced that it is building a solar panel farm containing 6 million panels. Improvements in the performance of solar panels are constantly being made, both in the amount of electricity produced per unit of light that hits the panels, and in the development of devices to cause the panels to move as the sun moves across the sky, so that more light is captured.

The number of panels in an array varies greatly, from rooftop arrays that service only the building they are on, to medium size arrays that serve a small community, to millions of panels as discussed above. The panels often produce more electricity than is needed during periods of sunlight, and the issue of what to do with the excess electricity is raised. The excess produced by rooftop arrays can be fed through the grid back to the utility companies; many states have laws requiring utilities to accept such feedback and give credits for it. The utility can then shut down all or part of its generators, and turn them on again at night or whenever the solar panels are not generating an excess. More on this when we discuss storage of electricity.

The New York Times reported on September 27, 2016 that there is a boom in the installation of solar panels in New York City, mostly in single family homes but also in apartment buildings. The report stated that the up front cost of solar panels for a private home can be between $20,000 and $50,000, but there are tax credits that can cut that amount in half.

Loans can be obtained to finance the purchase, and once in place electricity bills fall by as much as 85%. A rough estimate of the time needed for the savings in electric bills to pay for the installation is five years and after that the electricity is virtually free, so the savings are enormous.

The making of so much electricity by solar panels, and the laws and regulations which compel electrical utility companies to buy excess electricity, may create another problem: the electrical utility companies may become unprofitable. This is a problem because the electricity they produce will be needed for a long time whenever the sun is not shining or the wind is not blowing and backup power is required. They may need government subsidies, perhaps funded by taxes on electricity produced by sustainable means, or they may have to be allowed to raise their rates for off-hour electricity. A problem for the future, but one that is solvable.

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Figure 18 – Schematic Showing How a Solar Panel Works


***

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Figure 19 – An array of solar panels, which uses land that would otherwise be farmed.

13

Wind Turbines

Wind power has been around since ancient times, used to power sailboats, grind grain and pump water. In the 14th century wind powered pumps were used to drain lowlands in the Netherlands. Wind began to be used to make electricity in the late 19th century, soon after electricity usage became widespread. However its use for that purpose has not become economical until recently.

Like all electricity production other than solar, wind turbines produce electricity by pushing wires through a magnetic field. Their operation is depicted in Figure 20. Very simply, wind turns the turbine which turns the rotor, consisting of many layers of wires, through the magnetic field in the stator. The complexity is in determining the optimum size and shape of the rotor blades, the angle of rotor blades relative to the wind, the distance from one turbine to another, etc. Obviously, there are no emissions from wind turbines once they are running, although their manufacture and maintenance have carbon footprints.

Wind turbines vary enormously in size. There are small, individual turbines that serve farms and other areas not served by utility companies; there are wind turbines situated on buildings that serve just that building, and there are wind farms consisting of enormous numbers of large turbines. There are turbines designed to be on land and there are turbines located offshore. Offshore turbines are now much larger than land based turbines, and they are much more expensive to build, install and maintain. Presently the largest is a model designed to be used offshore, 722 feet tall (more than half the height of the Empire State Building), which generates 8 megawatts of power.

Today’s wind farm turbines are almost all three bladed and pointed into the wind by computer operated systems. The blades of land based models range from 66 to 131 feet and the towers are 200 – 300 feet tall, and they keep getting bigger. Turbines, since they have moving parts, do require maintenance and occasional replacement of parts.

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Figure 20 – Schematic of a wind turbine
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The largest wind farm in the United States is the Alta Wind Farm in California; it generates 1,320 megawatts (million watts) of power. The number of homes that can be served by one megawatt varies a great deal, between about 164 to 1,000, depending on the rate of usage.

So 1,320 megawatts can serve anywhere from 216,000 homes to 1.3 million homes. A much larger wind farm, which is really seven separate wind farms, is under construction in Ginsu Province in Northwest China; it is projected to generate 20,000 megawatts when it is completed in 2020, enough to power anywhere from 3.25 million to 20 million homes.

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Figure 21 – An offshore wind farm
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The cost of electricity produced by wind turbines varies greatly, depending on the cost of the wind turbine itself, whether it is land based or off shore, and the amount of wind it receives. On the whole the cost of wind produced electricity is competitive with utilities and, as with solar power, the cost is dropping.

This brings us to the obvious major drawback of wind turbines: they only work when there is wind. Offshore locations have steadier winds, mountaintops are better than valleys, and the windswept plains of the midwest, where there is little to block the winds, are better than the western states. So, as with solar power, until there is significant improvement in the methods of storing electricity, there is a need for backup from utilities.

An advantage that wind turbines have over solar power is that they can be placed in farms and crops can grow around them. The amount of land that needs to be allocated to wind turbines is therefore much less than for solar arrays.

There are two other disadvantages that need to be mentioned: wind turbines are quite noisy and therefore a wind farm cannot be placed too near to where people live. Also, there have been protests about the appearance of wind farms in areas with otherwise pleasing views, such as ridges in mountain ranges. Offshore wind farms solve the noise problem but there have been objections to wind turbines spoiling ocean views. I find them esthetically pleasing, more so because they are doing their bit to reduce global warming, but some people do not share my view.

Wind turbines do result in the death of birds that fly into them. The companies that manufacture wind turbines counter this objection by pointing out that cats kill about 10 times as many birds as wind turbines. The population of birds is not significantly impacted by wind turbines.

 

14

Nuclear Power

The method of producing electricity from nuclear fission is similar in many ways to those of fossil fuels. As in the schematic in Figure 22, heat produces steam, the steam turns a turbine and the turbine turns a generator consisting of wires in a rotor that turn through the magnetic field of the stator. That’s where the similarity ends.

The source of the heat is nuclear fission. There are many types of fission reactions; only one will be described here. Fission is the splitting of an element with very high mass into smaller elements. The total mass of the smaller elements is less than the mass of the larger element, and an enormous amount of energy is released in the process. Einstein’s famous equation, E = mC^{color:#fff;background:#298fb5;}2^, governs this process, where E is energy, m is mass and C is the speed of light. Since C is so large, 180,000 miles per second, and that number is squared, a small amount of change in mass yields an enormous amount of energy. This is also the basis for the power of the atomic bomb.

One of the elements used in nuclear reactors is Uranium, which exists in fairly large quantities in the Earth. It is even in ocean water so its availability is essentially unlimited, although it is not yet economical to separate it from ocean water. Most uranium, 99.3% of it, exists as U 238 ; only .7% of it is U 235. These numbers represent the atomic weight of the element, the sum of the protons and neutrons in the nucleus. Only U~{color:#fff;background:#298fb5;}235~ is usable in a nuclear reactor, and separating it from U~{color:#fff;background:#298fb5;}238~ takes energy. Once the concentration of U~{color:#fff;background:#298fb5;}235~ is sufficiently high (it is not completely separated from U~{color:#fff;background:#298fb5;}238~), it is usable as a fuel. Uranium is radioactive, which means that neutrons are emitted by some of the uranium atoms. They enter the nucleus of another U~{color:#fff;background:#298fb5;}235~ atom and cause it to split into two smaller atoms, for example Krypton~{color:#fff;background:#298fb5;}92~ and Barium~{color:#fff;background:#298fb5;}141~, and this releases the heat that powers the generating plant.

Notice that the sum of the atomic weights of the fission products is two fewer (92 + 141 = 233) than the atomic weight of U~{color:#fff;background:#298fb5;}235~. This is due to the release of two neutrons which go on to cause other uranium atoms to split. When this happens over and over again it is called a chain reaction and it becomes usable as a source of energy. Plutonium is also used as a fuel for nuclear reactors and many different products of fission have been discovered.

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Figure 22 – Schematic of a nuclear power plant.
p<>{color:#fff;background:#298fb5;}. The amount of material needed to power a nuclear plant is extraordinarily little: a couple of truckloads a year, compared to two 100 car long train loads a week for a coal fired plant.

The beauty of nuclear power plants is that they produce no greenhouse gases and for this reason many environmental groups support the building of new nuclear power plants. Due to the dangers posed by nuclear plants many other groups are opposed.

The biggest problem with nuclear power is that the fission reactions need to be controlled. If they become uncontrolled the heat produced is so great that the structures that hold them cannot continue to hold them and radioactivity (subatomic particles) are released into the environment. Depending on the dose of subatomic particles received by a person, the result ranges from mild sickness to severe burns to cancer to death. The reactions are controlled by water that cools the reaction and by rods of substances such as graphite which absorb neutrons and which can be moved, as needed, nearer or further from the radioactive substances. If pumps break or the mechanisms that move the graphite rods malfunction, the reactor becomes extremely dangerous.

There have been three major accidents in nuclear power plants: in the United States at Three Mile Island, Pennsylvania in 1979; in the Ukraine at Chernobyl in 1986; and in Japan at Fukushima in 2011. In addition there have been more than 100 other accidents which have been classified as serious but which have not released dangerous amounts of radiation. The one at Chernobyl was the worst: 31 people died at the time of the accident and it caused an estimated 4,000 additional cancer deaths. 350,000 people were resettled due to contamination of the countryside. The Three Mile Island accident released very little radiation and caused negligible health effects but it cost $2.4 billion to clean up. The meltdown at Fukushima was caused by an earthquake; two people died, although in time there are likely to be cancer deaths, and it is still being cleaned up at enormous cost.

The disposal of nuclear waste generated by nuclear power plants is a huge, unsolved problem. Nuclear reactions in power plants cause the material in contact with the radioactive material to also become radioactive. This includes cooling water, control rods, and the structure which houses the fission reaction. The radioactive material is classified as low, medium or high level. The length of time the material remains radioactive varies enormously from a few years to thousands and even millions of years. Low level material can be stored above ground but scientists generally agree that high level radioactive material should be stored in a safe manner, such as surrounded by glass and underground. However there is presently no underground storage facility anywhere in the world, although one is under construction in Finland, and radioactive waste is stored above ground in pools at each nuclear power plant. This is a serious constraint on the construction of new facilities.

Lastly there is the problem of the proliferation of radioactive material and its potential for use by terrorists. Radioactive material could be stolen from plants that refine uranium ore, from nuclear power plants, from missile sites and from waste disposal sites, since the waste can be reprocessed and made into bombs. There is also the fear that nuclear power plants could be attacked simply to cause the release of radioactive material. There is a group called Plowshares whose members have successfully trespassed onto property containing nuclear weapons in order to demonstrate the vulnerability of such sites and to call for the destruction of such weapons. The potential harm that could be inflicted by terrorists using nuclear material is incalculable.

Then there is France, where 75% of its electricity, and about 40% of its total energy is produced in nuclear power plants, without serious accidents. In the United States 19.5% of our electricity comes from nuclear power plants. We have 100 operating nuclear power plants, with 5 new plants under construction, and 33 plants have been closed due to their age and safety concerns. In addition to being emission free, nuclear power plants operate 24/7 and so they can serve as backup to wind and solar electrical generating systems.

There is also China, where the government plans to expand nuclear power massively. China started its first nuclear plant in 1994. There are now 36 reactors in operation, and another 20 under construction. A further four have been approved, and many more are in the planning stages. By 2030 China is projected to get 9% of its power from nuclear, up from 2% in 2012.

Should more nuclear power plants be built, given all of their advantages and drawbacks? That is the debate.

15

Hydroelectric Power Plants

With the exception of nuclear power, all of the methods of producing usable energy discussed previously (fossil fuels, solar panels, and wind turbines) derive their energy originally from the sun. Fossil fuels come from plants that grow with energy from the sun, solar power is obviously from the sun, and wind power comes from the unequal heating of the earth by the sun. Hydroelectric power derives its energy both from the sun, in evaporating water from the oceans which falls on to land, and from gravity, which causes water to flow downstream and thereby turn turbines to make electricity.

The power in moving water is harnessed by building a dam which creates a reservoir. At a point considerably below the surface of the water a pipe, called a penstock, penetrates the dam. The water that flows through the penstock is used to turn a turbine, which turns a generator and makes electricity in the manner we have seen several times before: pushing wires through a magnetic field. The distance from the surface of the water to the penstock is called the head; the greater the head, the more power can be delivered to the generator. A schematic drawing of a hydroelectric plant is shown in Figure 22 .

Hydroelectric power has been in existence since the earliest days of electric power, in the late 19th century. In 2015 it produced one sixth of the world’s electricity and 70% of the world’s electricity from renewable, non-polluting sources. In the United States we have about 2,000 hydroelectric plants, which produce 6.8% of our electricity, and 50% of all the electricity produced in the U.S. by renewable energy sources.

The advantages of hydroelectric power are significant. After a dam is built there are no emissions from hydroelectric plants. The cost of hydroelectricity is very low, only 3 to 5 cents per kilowatt hour. By way of comparison, in New York City electricity costs not less than 9 – 10 cents per kilowatt hour.

Unlike wind and solar power, it can operate at any time, and its output can be adjusted to meet the demands caused by a lack of production by wind or solar sources.

The largest dam in the United States is the Grand Coulee Dam on the Colorado River in Washington State, which generates 6,800 megawatts of power. It is dwarfed by the largest dam in the world, the Three Gorges Dam in China, which has an output of 22,500 megawatts. Canada gets 60% of its electrical power from hydroelectric power plants. Russia, Brazil and Norway are also significant users of this type of power.

There are significant disadvantages. Reservoirs flood areas that often were occupied by people and farms, resulting a need for extensive relocation. Fish stocks are disrupted, fish that are accustomed to swimming upstream to spawn can not longer do so, and the amount of fish downstream from the reservoir is usually much reduced.

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Figure 23 – Schematic of a hydroelectric power plant.
p<>{color:#fff;background:#298fb5;}. In Myanmar, a country in Southeast Asia adjacent to India, a plan was made to build a large reservoir and electric power station on the Iriwaddy River, which runs through the middle of the country. It would have produced a great deal of electricity, most of which would have been exported to China, and the millions of people who lived off the river downstream from the dam would have lost their livelihood. It was cancelled after demonstrations against it.

In the United States there are no places left where a large dam could be built without significant environmental and human impact, and so there probably will not be any more large dams constructed here. There may be smaller dams constructed to serve small communities.

Droughts have reduced the productivity of hydroelectric plants significantly, most notably in Brazil. The climate changes taking place throughout the world, creating droughts as well as floods, could affect other countries.

One more drawback: the flooding caused by the construction of a dam buries all the plant material in the reservoir and that releases methane into the atmosphere. As noted above, methane is a powerful greenhouse gas.

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Figure 24 – A hydroelectric power plant.

16

Biomass and Biofuels

Biomass is simply organic matter that comes from living or recently living plants. It has been an energy source since the time that humans began burning wood for heat and cooking. Today it is an increasingly important source of energy that helps in the fight against global warming. It is a very complex field because there are many different sources of biomass.

Using biomass as an energy source does release carbon dioxide into the atmosphere. So how, one may reasonably ask, does this combat global warming? The answer is that if the biomass comes from plants that grow quickly, and they are planted year after year, the carbon dioxide that is released comes from plants that have taken the same amount of carbon dioxide out of the air by photosynthesis as they grew. Thus the assumption is that the use of biofuels for energy does not increase the carbon dioxide content of the atmosphere. This is in contrast to the burning of fossil fuels which release CO~{color:#fff;background:#298fb5;}2~ without recapturing it.

A recent study disputed this assumption and found that only about one third of the carbon dioxide released by the burning of ethanol was taken up by the corn that is used to produce it. There is disagreement between scientists on this issue; more research is needed. Perhaps other forms of biomass will be better at recapturing carbon dioxide.

One of the main advantages of biomass is that it can produce a liquid product. This is very important because the energy source for transportation, as least at the present time, has to be in liquid form. Internal combustion engines that power our vehicles use liquid fuel, which can be transported easily to the vehicles and carried easily by the vehicles as it is being used. The same is true of jet engines. It is not feasible to convert these engines so that they can use solid fuels.

One way of converting solid biomass into liquid biofuel is fermentation with yeast or other bacteria to produce ethanol, a kind of alcohol. In the U.S. gasoline is already 10% ethanol; in Brazil, where it has been used for 40 years, gasoline is 22% ethanol.

The burning of a biofuel such as a tree is not useful in reducing the amount of carbon dioxide in the atmosphere because trees grow very slowly. It takes as long as 50 years for the CO~{color:#fff;background:#298fb5;}2~ released into the atmosphere by burning a tree to be taken up by a new tree. Despite this, trees and other materials found in forests, such as leaves and branches, are used extensively in underdeveloped countries and are the most common biomass fuel in the world.

Biofuels are responsible for only about 1.4% of the energy used to produce electricity in the United States, and about 5% of the energy used for transportation.

However, there is a great deal of research underway to find cheaper and better ways of using biofuels and since the amount of biomass in the world is enormous, it can become a significant alternative source of energy.

The plants that can be used as biofuels vary depending on the region. In the United States it is primarily corn, which grows quickly and is replanted each year. In Brazil it is sugarcane. In Southeast Asia rice husks are used, while in Britain it is poultry litter that becomes fuel.

The ethanol made from corn in the U.S. has created another problem. Corn has been a significant export, as food, to several countries, including Mexico. Since it became more profitable to use corn to make ethanol for fuel, the amount available for food has declined, the price has risen, and the result is a food shortage in Mexico. One of the disadvantages of biofuels is the amount of land needed to make it and the effect this has on the food chain.

An encouraging avenue of research is the use of algae grown in the ocean as a source of energy. It could be fast growing, inexpensive, have no effect of food production, and be very plentiful.

17

Geothermal Energy

When the Earth formed 4.5 billion years ago the gravitational forces that pulled the rocks and molecules together made them hit each other and this generated a great deal of heat. The other source of heat in the Earth is the decay of radioactive elements such as uranium which has been described in Chapter 14. Although the Earth has been slowly cooling much of that heat remains under the Earth’s surface. The center of the Earth is estimated to be about 12,600 degrees Fahrenheit. In areas near the boundaries of tectonic plates temperatures can be high enough so that steam is produced and it is in these areas that the Earth’s heat can be easily harvested.

The geothermal energy of the Earth is obtained in several different ways. In some areas, such as The Geysers geothermal field in California, in Iceland and in the Philippines, steam is harvested simply by drilling into the Earth and the steam that comes out of the pipes is used to turn a turbine. In other areas pipes need to be pushed deeper into the Earth and pumps are needed to circulate water into the warmth to produce steam to turn a turbine. Hydraulic fracturing is employed to assist in this process, but, unlike in the harvesting of gas, water under pressure is used without the addition of harmful chemicals so drinking water supplies are not endangered.

In some areas the heat is harvested only as hot water, which is then piped to homes and commercial establishments. This is the case in Reykjavik, Iceland, where more than 90% of space heating is from geothermal sources.

Except for a small amount of carbon dioxide, hydrogen sulfide and nitrous oxide that escapes into the atmosphere when steam is harvested, the carbon footprint of harvested steam is very low. However, when pumps are employed, and the electricity that powers the pumps comes from plants that burn fossil fuels, much of the environmental advantage of geothermal energy is lost. This should change in the future as more electricity is produced by non-fossil fuel methods.

The cost of harvesting geothermal energy is very varied and except in certain areas it is not yet economical. However scientists have calculated that all of the Earth’s energy needs could eventually be supplied by geothermal sources and technological improvements could make this form of energy viable.

 

18

Tidal Power

The power to make electricity from the movement of tides comes from the force of gravity. The moon, and to a lesser extent the sun, gravitationally pulls on the Earth, causing the level of the oceans to rise where the pull is strongest, at the closest point to the moon. As the Earth turns and the moon revolves around the Earth, the location of the force on the oceans changes and the level of the ocean changes in response. At shorelines this is seen as tides, an inflow and outflow of water that is periodic and very regular.

Tidal forces vary a great deal at different coastlines. One factor is the slope of the land at the shoreline. Where the slope is steep water will rush in quickly; where the slope is gradual the speed of the water flowing towards and away from the land will be less. There are other factors that affect the suitability of a site for tidal power generation.

The fundamental principle of the use of tidal power is simple: the water coming towards and away from the land is used to turn turbines which generate electricity. Turbines can be placed against bridge supports or at any point below the surface of the water. Another method is to construct a dam near the shoreline at a point where a river flows into the ocean, similar to that shown in Figure 22 in Chapter 15, and as the water flows into and out of the estuary through openings in the dam it can turn turbines.

Such dams have negative environmental effects on fish, as described in Chapter 15. Also, since the dams may be near oceans, they may affect marine mammals such as whales and dolphins, which have become entangled in the turbines. The turbines make noise and affect the ability of marine mammals to communicate with each other and to navigate by echolocation.

There are several tidal power stations in operation in the world; one in France has been in operation since 1966. The largest in the world is in South Korea; it opened in 2011. There is ongoing research on the use of tidal power, but thus far it has not been found to be economical. Stay tuned for future developments since tidal power has some very strong advantages: no emissions, power is generated without interruption, and there is an endless supply of gravitational forces to power it.

 

19

Storing Electricity

As you now know, solar panels and wind turbines produce more electricity than can be used at certain times, and none at other times. Many states have laws that require electrical utilities to absorb the excess electricity, which causes meters in homes to run backwards. So what do we do with this electricity? How do we store it and draw on it at times when little or no electricity is produced?

There is a big difference in the way electricity is stored on a small scale and the way it is stored by utilities on a large scale. Small scale storage is done with rechargeable batteries, such as those in cell phones, with which we are all familiar. On a larger scale rechargeable batteries capable of storing enough electricity to drive a car for 300 miles are now available in Tesla automobiles. Large size batteries are also being used in homes with solar panels. There are many different kinds and sizes of batteries and research is ongoing to improve batteries.

Bulk storage of electricity by utility companies is accomplished by pumping water from a lower level into a reservoir at a higher location and then, when more electricity is needed than is being produced, water is let out of the reservoir through turbines, as described in the chapter on hydroelectric power. Almost all electricity storage by utilities is done in this manner. In some cases the water is pumped from a lower reservoir into a higher one, while in others it is pumped to a higher location from a stream or river.

Utilities report an efficiency level of 70% to 80%, meaning a loss of between 20% and 30% of the electricity produced, which is quite good.

There are two large hydroelectric storage facilities in the United States, one in Virginia and one in Michigan. China also has two large facilities and Japan has one. The disadvantages of this technology are that it can only be employed in hilly areas, and, as mentioned in the chapter on hydroelectric power, building reservoirs has many environmental drawbacks. The best locations for such facilities are often in wilderness areas.

Research is ongoing into other methods of bulk storing of energy. One idea is to use excess electricity to raise a weight, either up a hill or a tower or a tall building, and then when power is needed, let it down in a manner than turns a turbine. Stay tuned for progress in this very important field.

 

20

Climate Engineering or Geoengineering

These terms refer to large scale efforts to change the climate of the Earth to limit climate change, as opposed to efforts to limit carbon dioxide emissions. One type of measure seeks to remove carbon dioxide from the atmosphere and another type attempts to offset the effect of carbon dioxide emissions by limiting the amount of solar radiation that reaches the Earth.

Carbon dioxide can be removed from the oceans, which would lower the concentration in the atmosphere, by marine organisms which have carbon in their shells and which sink to the bottom of the sea when they die. Algae blooms near the surface of the ocean perform this function.

There are large areas of the ocean that are devoid of algae and scientists have discovered that the main nutrient that is missing and preventing the growth of algae is iron.

The idea is to distribute large quantities of iron, as very tiny particles, which will cause the algae to grow and carbon dioxide in the air and in the ocean to decline.

Tests have been done which have found that the role of iron in producing algae blooms is very powerful. One pound of iron, in particles of one millionth of a meter or less, was found to cause an algae bloom that removes 83,000 pounds of carbon dioxide.

So why not do more of this? Because no one knows what negative effects this may bring. Some algae blooms are poisonous to fish; others are nutritious. Some algae blooms remove too much oxygen from the water, causing fish to die. History is full of interventions, such as the importation of plants and animals to areas that did not have those species, causing unforeseen disastrous outcomes.

Scientists have estimated that if this technique were successful and employed in many areas of the ocean that are now devoid of algae, it would still only remove about one sixth of the excess carbon dioxide that is causing the Earth to warm. So it cannot be a panacea and it may be very harmful.

Global warming can also be abated by limiting the amount of solar radiation that reaches the Earth. The idea is to block the sun’s rays by spraying sulfate aerosols into the upper atmosphere. Proponents cite the fact that this would be relatively inexpensive, and would probably work to reduce the Earth’s temperature. In support of their contention they point out that when there have been large volcanic eruptions the temperature of the Earth has been lowered slightly for varying periods, usually about two years.

The potential side effects of sulfate aerosol spraying are enormous and potentially disastrous. The carbon dioxide content, and therefore the acidification, of the oceans would continue to rise. The sulfates in the aerosol would form acid rain, further wiping out fish. There could be disruptions in the growth of plants and therefore food shortages and famines. Atmospheric wind currents could be altered, causing unknowable effects on weather patterns, including droughts. Fortunately there have been no trials of aerosol spraying.

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Figure 25 – Geoengineering proposals.
p<>{color:#fff;background:#298fb5;}. Proposals have also been made to send mirrors into space to block sunlight but the cost is wildly prohibitive. One estimate put the cost at 26 times our current national debt, about 200 trillion dollars. The downsides would be the same as with aerosols, with the exception that acid rain would not be produced.

Carbon capture and storage, also called carbon capture and sequestration (CCS) is a more mainstream geoengineering solution to the problem of increasing carbon dioxide. It involves capturing the carbon dioxide emissions from power plants, injecting it into geological formations deep underground, or combining it with other materials to form solids that can either be buried or used. There are about 75 CCS facilities in operation in the world, using many different methods, and a great deal of research is underway to improve the processes. None have been commercially successful yet. The details of the chemistry involved in these processes is beyond the scope of this book.

One experimental process that shows promise has been used in Iceland to sequester the carbon dioxide that comes out of the earth naturally in a geothermal power plant. The CO~{color:#fff;background:#298fb5;}2~ is dissolved in water, forming soda water, and pumped into a kind of volcanic rock called basalt, which is abundant. A mineral called calcite is formed and this appears to be stable. A problem is that a great deal of water is needed, 25 tons for every ton of CO~{color:#fff;background:#298fb5;}2~, which could be solved only by placing the sequestration plants near coasts and using sea water. Another problem is getting the carbon dioxide to the areas where basalt exists.

The challenge is in making this process commercially feasible; if that happens it means that fossil fuels can continue to be burned without causing global warming. The organizations fighting global warming, and most environmental scientists, do not believe that CCS, without extensive development of alternate energy sources, can solve the problem of global warming.

The one kind of geoengineering everyone supports is planting more trees, reforestation, discussed in Chapter 4.

21

Opportunity and Organizations

The world is changing and it is changing fast. Along with all the dire changes flowing from global warming, there are changes in energy production that mean opportunities and exciting work for people coming of age now and in the near future.

Every one of the alternate ways of harnessing energy involves a separate field of scientific study, a separate field of engineering, new requirements for consultants and technicians and new business opportunities. The simplest and most accessible is the opportunity to advise businesses and homeowners on the ways they can save energy and money.

Studying science and engineering is the obvious pathway into these fields but that is not everyone’s bent. There is also a need for the hands on technicians to install and maintain the alternate energy sources; entrepreneurs to build the organizations to accomplish the tasks needed to convert our society; bankers to finance the organizations; and so on.

There are many organizations participating in the struggle against global warming. Activists have been energized by successes on several fronts, including the decision by President Obama to block offshore drilling along the Atlantic Seaboard; his decision to reject the Keystone Pipeline; adoption by the Environmental Protection Agency of regulations which will force coal fired plants to close; and the Paris Climate Agreement of 2015 in which 195 countries, including the U.S. and China agreed to take steps to limit global warming to 2 degrees Celsius. There have also been setbacks, the most notable being the election of Donald Trump who has said he will repeal many of the regulations put in place during the Obama administration.

The organizations run the gamut from those engaged in militant civil disobedience to those which espouse working with government agencies, fossil fuel companies and banks. Here are a few of them.

350.org is among the largest, with grassroots efforts in 188 countries. Its efforts include demonstrating at events like the Paris Climate Conference, and supporting local native groups who are opposing mining of fossil fuels in the Alberta Tar Sands. It advocates very aggressive efforts, such as was done in World War II, to change the way energy is produced and quickly end the use of fossil fuels. Its members have engaged in civil disobedience.

The Union of Concerned Scientists is an alliance of scientists and engineers who do research and advocacy work in many fields, including climate science. It publishes papers and holds meetings with corporate and government leaders and the general public to publicize analyses and make recommendations on ways to reduce global warming.

Greenpeace is a militant grassroots organization engaged in activities to save the arctic, save forests, save the oceans, and end global warming. It has engaged in militant activities such as boarding an oil rig in the ocean, as well as demonstrating with native peoples who are opposing destructive development.

Sierra Club actions have historically been more diplomatic than militant, including lobbying, litigation, grassroots activism, education and working within the electoral system to promote its principles. The organization claims success in halting the construction of more than 170 coal plants and working to close another 129. In the past year, however, it has become more militant and has participated in civil disobedience to halt the Keystone Pipeline, which was stopped.

The Environmental Defense Fund is a moderate organization with the same goals as many of the more militant organizations but with a willingness to negotiate with large corporations for modest results. EDF negotiated with the Texas energy company TXU for a reduction in emissions; other organizations have the goal of putting such companies out of business.

Wikipedia has an enormous amount of information on all of the topics in this book, including organizational activity.

A web site which lists organizations all over the world which are fighting global warming has hundreds of groups listed. It includes Green Parties in many European countries.

Join the movement!

 

Table of Contents

  1. Copyright
  2. How Much is the Earth Warming?
  3. Why is the Earth Warming?
  4. The Effects of Global Warming
  5. Deforestation and Reforestation
  6. How We Use Energy
  7. Where Our Energy Comes From
  8. How Electricity is Made
  9. Coal
  10. Petroleum
  11. Natural Gas
  12. Saving Energy
  13. Solar Panels
  14. Wind Turbines
  15. Nuclear Power
  16. Hydroelectric Power Plants
  17. Biomass and Biofuels
  18. Geothermal Energy
  19. Tidal Power
  20. Storing Electricity
  21. Climate Engineering or Geoengineering
  22. Opportunity and Organizations

Global Warming: What You Need to Know

  • ISBN: 9781370631322
  • Author: BooksWithAPurpose
  • Published: 2016-12-26 19:20:21
  • Words: 16092
Global Warming: What You Need to Know Global Warming: What You Need to Know