As you read before, fossil fuels are a major cause of climate change. You know that fossil fuels, when burned, release greenhouse gases. But how does it work?
To release energy, fossil fuels must first be extracted from the ground and then refined. When burned, hydrocarbons inside the fossil fuels create energy. This is because of the heat that is used to burn fossil fuels causes large amounts of carbon and hydrogen to react and creates energy. This is used in different ways.
Coal is the cheapest fossil fuels, but it takes a long time to create. Coal is the decayed remains of millions of years old plants. Coal is used mainly in power plants to create energy. When coal is burned, the chemical energy inside the coal becomes heat or thermal energy. That is transferred to kinetic energy and it creates steam. This steam is used to turn the turbines of the power plant. This sounds a lot like geothermal energy, except for one key factor. During the burning process of coal, carbon dioxide is released into the atmosphere. Coal has a high carbon content, ranging from 60-80%. During the combustion of coal, all of that carbon dioxide is released into the atmosphere. As an active greenhouse gas, carbon dioxide is one of the major contributors to climate change.
The pressure and heat inside Earth creates oil, but at a slower rate than we use it. It also requires dead animals that are millions of years old. Once oil is refined, it is ready to pump to the gas station. Once in your car, oil (gasoline) acts in a similar way to coal. The engine of the car burns the oil and it releases heat energy. The heat energy then goes through pistons, converting it to mechanical energy to power the car. However, during the combustion of the gasoline, the oxygen combines with the carbon in the gasoline and it creates carbon dioxide. This is how cars release carbon dioxide. To continue reading about cars, click here. However, oil also releases a different type of emissions that is during the refining process. It releases methane, a potent and short-lived greenhouse gas. This byproduct of oil refinement is also known as natural gas.
Natural gas is formed during the pressure reduction process of oil, or oil refinement. It is considered another type of fossil fuel. Natural gas is collected by capturing the methane and ethane released from the oil. Thankfully, this prevents oil from polluting the environment during the refining process, but it then starts a whole new fossil fuel process. Once captured, natural gas is transported across the world and used for gas stoves and heating. This is because natural gas is very flammable. When we burn natural gas, the chemical energy is changed to heat energy, which powers the utilities that we use. However, during the combustion process, natural gas releases it's internal carbon dioxide. Natural gas can also be used for generating electricity via turning turbines. However, natural gas is methane, and during the transportation process it leaks. This means that natural gas has a larger footprint than it is credited for.
To sum up, all fossil fuels use heat energy and combustion. During the combustion process, carbon dioxide is released into the air.
As you just learned, cars release emissions because of the combustion process with gasoline in their engines and the combination of oxygen and carbon. Burning one gallon of gas releases 19.64 pounds of carbon dioxide. The average car releases 5 tons of carbon dioxide a year, assuming a miles per gallon rate of 22 and driving 11,500 miles a year. However, trucks are a different story. While there the amount of carbon dioxide per gallon is the same because it is the same fuel, the miles per gallon is a lot less. For a tractor trailer, the average miles per gallon is 6. That means that if we assume the same mileage for a truck, we can say that a tractor trailer produces 37,650 pounds, or 18.83 tons, of carbon dioxide in a year.
That is a large amount of carbon dioxide, and that is why cars are a major cause of climate change.
The U.S. Transportation Sector includes more than just cars. It includes all methods of transportation, including planes, buses, trains, and marine craft. In all, the U.S. Transportation Sector produces 28% of the American greenhouse gas emissions. Of that 28%, 60% is cars and light vehicles, 23% is trucks and heavy duty vehicles, 9% is aircraft, 4% is other, 2% is rail, and 2% is marine vehicles. That is clear that cars are a major part of the American greenhouse gas emissions.
Agriculture and Livestock
Fertilizers help feed plants by putting nitrogen into the soil. Soil bacteria takes advantage of this nitrogen and uses it. However, in the processes of nitrification (adding nitrogen to the soil) and denitrification (plants taking the nitrogen from the soil), nitrous oxide is created and released into the atmosphere.
When soil is saturated for 36 hours or more, denitrification can occur, and nitrous oxide can be released into the air.