# What Does It Mean?

Some scientists have said that the levels of carbon dioxide (CO2) in the atmosphere have risen dramatically in the past 100 years because of human activities. These activities include the burning of fossil fuels and deforestation. This increase has been confirmed by analysis of atmospheric air trapped in the ice caps and glaciers around the world.  But are human activities entirely to blame?

The world industrial revolution occurred between the 1700s and 1800s. The use of fossil fuels and the wide-scale land use and deforestation was minimal before this time. Any changes in the levels of carbon dioxide would have been mostly natural before then.

Carbon dioxide is a greenhouse gas. This means that increasing levels of CO2 will lead to an increase in global temperatures, which will cause the ice caps to melt.  This will increase the sea levels, which will put a large percentage of Earth's population underwater. This is the "Greenhouse Effect" hypothesis, and its accuracy is widely debated.

Let's take a look at data connected to this issue over the past 100 years. Below is a data table listing the average carbon dioxide level in parts per million and the global average temperature in degrees Celsius.

Year CO2Level (ppm) Ave. Temp. (deg C) Year CO2Level (ppm) Ave. Temp. (deg C)
1900
295.8
14.94
1955
313.0
14.89
1905
297.6
14.71
1960
316.3
15.07
1910
299.7
14.62
1965
320.0
14.92
1915
301.4
14.93
1970
324.8
15.05
1920
303.0
14.85
1975
330.3
14.96
1925
305.0
14.84
1980
339.0
15.19
1930
307.2
14.92
1985
346.1
15.09
1935
309.4
14.91
1990
355.9
15.42
1940
310.4
15.05
1995
360.9
15.46
1945
310.1
15.14
2000
369.4
15.37
1950
310.7
14.87
2005 (est.)
________
________

Prepare a graph based on this data to better visualize the trends in CO2 and temperature to see if there is an apparent relationship.

Analysis:

1. Based on the trends of the data, estimate the carbon dioxide level and average temperatures for 2005.
2. Describe any relationship between the levels of CO2 and temperatures around the globe.
3. Does this data support or invalidate the global warming hypothesis? Justify your answer.
4. Ice core data shows that the CO2 levels in the years 1663 and 1683 were measured at 279 ppm. In 1723 it was 280 ppm and in 1743 it was 284 ppm. Are these levels dramatically different than the levels in the early 1900s?
5. Is human activity entirely to blame for the changes in atmospheric CO2? Justify your answer.
6. Is 100 years enough data to show global trends in climate? How many years would be necessary?
7. Is the rise in temperature due only to the carbon dioxide levels in the atmosphere, or are there other factors that affect the temperature. What are they?

Review science lab safety rules here.

Get the plug-ins: and . (The QuickTime plug-in is needed to play sounds and movies correctly.)

Want to share photos of you or your friends doing this activity? Send it in an e-mail with the following information:

1. The title of the activity

Remember that no pictures can be used that show student faces or student names on it.

Teachers should view the Teacher Site Map to relate Sci-ber text and the USOE Earth Systems Science core.

Updated October 24, 2008 by: Glen Westbroek