Earth's Warming Climate: Are We Responsible?


The CO2 – Temperature Connection

Scientists would not be so concerned about increasing CO2 if there were not a strong correlation between atmospheric CO2 levels and temperature. Read the article and explore the graphs from "Canaries in the Coal Mine" to see the Vostok CO2 record you have just examined plotted next to the temperature record for the region, as reconstructed from paleoclimate, or proxy climate, data sources.

Now, look at the "Global Temperature (1880-2009) and CO2 (1000-2009)" graph, which plots global temperature (black) and atmospheric CO2 in the recent past. The strong correlation between the two are viewed as compelling evidence that increased CO2 emissions are responsible for the warming trend seen in the climate data.

Think about what you have learned so far and then answer the following questions.

  1. Explain the rate and trend you see in the CO2 data that you have analyzed. What do you notice about the trajectory and rate of change in CO2 concentrations in the last century, compared to the almost-half million year record?


    The amount of CO2 in the atmosphere increased dramatically by the beginning of the 1800s, when fossil fuel combustion began to increase exponentially—causing an increase in atmospheric CO2.

  2. What implications do you think the rate of change may have for our future climate?


    By extending the trend line, if we continue adding CO2 at this rate, global warming will continue.

  3. There are some differences in values exhibited between the different sources of data. Can you think of some reasons why this might be the case? Do these differences weaken the case for increasing CO2 levels being a direct cause of contemporary global climate change?


    Each of the different data sources is measuring CO2 differently: the satellite is gauging the amount of CO2 by measuring the amount of reflected sunlight from the atmosphere that is reflected back into space; instruments at Mauna Loa measure CO2 directly with sensors, and the ice cores contain air bubbles where the fraction of CO2 is measured. Scientists believe that because the story told by these three data sources are the same, despite the different methods used, the scientific data is even more robust.

Now that you have examined scientific data showing increases in both atmospheric CO2 and the Earth’s average temperature and analyzed changes in atmospheric concentration of CO2 over time, think about how you can apply this experience to your instruction.

How might you use the data activities in this module with your students? What modifications or changes would you make to the activities to help your students understand anthropogenic (human-caused) climate change?

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