The changes in the levels of carbon dioxide (CO2) on Earth happened naturally until nearly 200 years ago.  During the Industrial Revolution of the early 1800's, a new factor was thrown into the equation.  When wood and fossil fuels like coal, oil, and natural gas are burned, CO2 is released in large quantities.  Oceans and vegetation absorb the gas.  Due to the widespread cutting of trees to produce goods in the 1900s, few remained to soak up excess CO2.  In 1920, atmospheric CO2 stood at about 280 parts per million (ppm).  By 1996, it had risen to 356 ppm. Make a line graph connecting the data points given in the reading above.  Extend this line in both directions.  Assume that the levels of CO2 grow at a constant rate over the years. Use the data from the line graph, predict the levels of CO2  for the years shown below and enter the values in the chart below to create a bar graph.  You must make sure the delete the "?".  After you have entered the data for the years 1935-1980, hit the reload or refresh button on your browser.  Print your graph and include it in your investigation.

special thanks to for the  great java script for the graphs Write a paragraph about the patterns you see in your chart.  Use the terms function, independent variable, dependent variable, domain, and range. Based on the relationships you found in the previous question, determine how much CO2 was in the atmosphere in 1800 and in 1950 (hint: use the line drawn in the first part of this page). Explain how you found those amounts. Predict the amounts of CO2 that will be in the atmosphere in the years 2000, 2020, 2050, and 3000.  Explain how you made your predictions. All graphs should be labeled clearly and on graph paper.  Include the printout of the graphs above. Title this portion of the Investigation "The Greenhouse Effect --  page 4"

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