We know that concentrations of carbon dioxide, nitrous oxide and methane have risen based on direct measurements of atmospheric concentrations of these gases taken regularly for much of the past half century and estimations of historical levels based on data from ice cores. Open the Climate Trends Learning Tool and briefly read through the 'Getting Started' page to learn how to use this Learning Tool. Then enter the Learning Tool and answer the following questions.

Your Turn

How do changes in temperature and atmospheric carbon dioxide concentration relate to each other? Use the Climate Trends Learning Tool as necessary.

When a fluctuation occurs, does the temperature or the carbon dioxide concentration increase first? Is this consistent for each fluctuation? What might be the significance of this?