Living in a Carbon World

Part D: Fossil Fuels, Hydrocarbons and CO₂

On April 20, 2010, the Deepwater Horizon oil rig operating in the Gulf of Mexico exploded and sank. Oil and gas moved up the drilling well-bore onto the deck causing a massive fire. The explosion killed 11 platform workers and badly injured 17 others. Following the explosion and sinking of the rig, oil gushed up from the sea floor unabated for 87 days. An estimated 4.9 million barrels of crude oil spilled into the Gulf of Mexico waters inundating the coastlines of Louisiana, Mississippi and Alabama, and damaging coastal ecosystems and fishing industries.

The oil and gas extracted by the DeepWater Horizon rig had been formed and buried in deep sediments millions of years ago. While coal had been used as a fuel resource since 1000 B.C, it wasn't until the arrival of the Industrial Revolution that coal began to replace wood biomass as the primary source of energy. Today, humans are extracting the three primary fossil fuels - coal, oil, and natural gas - to provide energy for a world population that has exceeded 7 billion. Fossil fuels are made of hydrocarbons energy rich organic carbon compounds made of carbon and hydrogen atoms. . In this section of Lab 1, you will investigate how the combustion of fossil fuel hydrocarbons is changing the chemistry of the atmosphere.

Burning hydrocarbons releases energy, and CO₂ as a by-product

The Deep Horizon rig was drilling for crude oil (petroleum) deep within bottom sediments in the Gulf of Mexico. Crude oil is a mixture of several different chemicals which can be refined into hydrocarbon products such as such as motor oil, gasoline, jet fuel, diesel fuel, and heating oil. If you drive a car, heat your home, turn on a light, or enjoy a good backyard barbecue, the energy you are using most likely comes from burning fossil fuel hydrocarbons, a process called combustion the process of burning something; example is when a substance such as wood, coal, or gas reacts with oxygen to produce carbon dioxide, water vapor, heat, and energy .

To learn some important facts about combustion and hydrocarbons, watch this 7-minute video on combustion. Before you watch the video, make note of the Checking In questions below. You will need to answer these questions when you finish watching the video.

Hydrocarbon molecules have energy-rich bonds

Consider the combustion reaction of methane below. Combustion produces energy but where does this energy come from?

Methane (CH₄) + 2O₂ —> CO₂ + 2H₂O (water vapor) + heat energy

Energy is stored in the chemical bonds that hold the carbon and hydrogen atoms together. When the atoms are rearranged in the combustion reaction, bonds are broken and new bonds formed, releasing energy. The chemical energy stored in these bonds originated from solar energy used by plants to power photosynthesis. During photosynthesis, plants transform solar energy to biochemical energy which becomes stored in the bonds of glucose molecules and other carbon compounds made by plants.

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Formation of Fossil Fuels

Provenance: U.S. Department of Energy
Reuse: This item is in the public domain and maybe reused freely without restriction.

Fossil fuels are made of hydrocarbons produced millions of years ago

We use fossil fuels on a daily basis but do we know their origins? Contrary to what many people believe, fossil fuels do not come from the remains of dead dinosaurs. In fact, fossil fuels were formed 300 million years ago during the Carboniferous period, before the first dinosaurs evolved. Take a view minutes to examine the image pictured on the right and then watch the video on fossil fuel formation below.

Humans are extracting and using large amounts of fossil fuel, but how much?

Click here:How much fossil fuel has been used in your lifetime? to enter an interactive created by The Guardian. Click through the interactive until you find out how many barrels of oil, tonnes of coal and cubic meters of gas have been extracted since you were born.

Are humans changing the chemistry of the atmosphere? How do we know?

Humans have been burning large amounts of fossil fuel hydrocarbons for energy since the Industrial Revolution. Today, approximately 75% of the world's energy needs are fulfilled by burning fossil fuels. We certainly can't get along without fossil fuels at the present, but are we creating a problem when we burn millions of metric tonnes of fossil fuels every year? 

Watch this NASA video to find out if we are creating a "Gas Problem" when we burn fossil fuels.

Laboratory Investigation: Are humans changing the chemistry of the atmosphere?

The video you just watched makes the claim that when humans burn fossil fuels, we release CO₂ to the atmosphere causing the atmosphere to become warmer. However, the video provides no data as evidence to support this claim. As a matter of fact, some people on the Internet have claimed that humans have no role in rising CO₂and instead blame the rise on natural events such as volcanic outgassing. Providing evidence for a claim is a critical component of science. To that end, you will analyze data from a series of graphs, a NASA animation of CO₂ emissions and a video presentation given by geoscientist Dr. Richard Alley. As you analyze the data, you will decide whether the data provides evidence that strongly supports, partially supports, or strongly refutes the claim that humans are changing the carbon chemistry of the atmosphere and that this change is leading to a warmer atmosphere. With a peer or small group:

1. Create a 5-column table with the following headings:

• Column A: Title of graph(s) and video
• Column B: Type of evidence (ex. CO₂ data, carbon isotope data, etc. )
• Column C: Evidence strongly supports the claim.
• Column D. Evidence only partially supports the claim (i.e., the evidence is incomplete).
• Column E. Evidence strongly refutes the claim. NOTE: in Columns C-E, make sure you describe the evidence and explain why the evidence strongly supports, partially supports or strongly refutes the claim.

• Click on the links below to view the graphs and watch the video. NOTE: Your teacher may decide to assign different graphs to different groups for a jigsaw activity.
  • Graph 1: Illustrates the amount of CO₂ emissions moving into the atmosphere from the combustion of the three most important fossil fuels: oil, gas, and coal from 1880-2004. Click to enlarge.
  • Graph 2 and Graph 3: Go to NASA's Global Climate Change - Vital Signs of the Planet to investigate changes in atmospheric CO₂ data. Once there, analyze the following two graphs:
    • Graph 2: Direct Measurements of CO₂: 2005 to Present. This data represents the amount of CO₂ (parts per million) in the atmosphere directly measured from NASA satellites
    • Graph 3: Proxy Measurements of CO₂. This data was taken from CO₂ bubbles found in ice cores core sample that is typically drilled and removed from an ice sheet, most commonly from the polar ice caps of Antarctica, Greenland or from high mountain glaciers elsewhere. .
  • Graph 4: Go to NASA's Vital Signs for Global Land-Ocean Temperature Index. This data represents temperatures that are above or below a 30 year average of temperature measurements taken from 1950-1980.
  • Graph 5: 1000 years of Fossil Fuels This video of graph 5 from climatecommunication.org allows you to compare trends in three datasets: fossil fuels, CO₂ and temperature.
  • Video 1: NASA, a year the life of Earth's CO_{2 .} In this video animation, NASA scientists have compressed a year's worth of CO₂ data into one year. Can you identify the three areas of the world producing the most CO₂?
    If the video does not play, watch here: NASA | A Year in the Life of Earth's CO2 - YouTube or on Vimeo
    
    
  • Video 2: How do scientists know where the extra CO₂ is coming from? Geoscientist Dr. Richard Alley explains the science behind this very important question in the video "Its Us." 
    NOTE: Pause and rewind portions of the video as needed.
    If the video does not play, watch here: How to talk to an OSTRICH: "IT'S US" - YouTube or at Earth: The Operators' Manual: Video Segments

Optional Extensions

Want to learn more about fossil fuels and hydrocarbons? Check out these resources!

• Research the latest research! New research on the carbon cycle, climate and the environment is on-going. You can use ScienceDaily and Phys.org to research recent research on the relationship between fossil fuels the carbon cycle, by using combinations of the following tags: carbon cycle, carbon emissions, hydrocarbons, fossil fuels, carbon dioxide. Here is an example: Bacteria in the world's oceans produce millions of tons of hydrocarbons each year
• Watch this video of 300 years of fossil fuels in 300 seconds
• Take this energy quiz and explore the Department of Energy site.
• Explore crude oil (petroleum)
• Watch a video on how scientists measure CO₂ from ice cores in Ice Core Secrets Could Reveal Answers to Global Warming - Science Nation
• Investigate the Deep Horizon Oil Spill: An interactive Look at What Happened
• Explore carbon's history, carbon emissions and carbon research in this interactive site from Global Carbon Atlas
• Investigate Carbon Emissions: Past, Present and Future from the World Resources Institute
• Explore the Each Country's Share of CO₂ Emissions