Test your knowledge by working through the following questions. Refer back to the lesson pages and the Climate Trends learning tool (linked below) as needed.

1. What has ice core data shown about climate change?
2. Challenge: Compare the heavy water to light water ratio found in ice cores during a glacial period to the ratio found during an interglacial period. Explain why the isotopic ratios differ.
3. What are the uncertainties, areas for further research or questions raised by the data from the ice cores?
4. Challenge: Which is more reliable: data taken from ice cores or data taken from cores of soil in North America? Why?

5. Written historical records and tree ring temperature data give evidence that a "Little Ice Age" occurred in Europe between the 16th and 19th centuries. Look in the Climate Trends learning tool to see if there is evidence of this ice age. Did you expect to find this temperature trend in the ice core data from Antarctica? Why or why not? (Hint: Use the events option).
6. Using the Climate Trends learning tool, find a time period during the past 800,000 years in which the Earth transitioned from an ice age to an interglacial period. Use the slope tool to find the rate of temperature change. Why might the climate change that is occurring today be different than temperature changes that have occurred in the past?

7. In the Climate Trends learning tool, notice that the concentration of carbon dioxide in the last 50 years has been determined by air sampling. This data demonstrates regular concentration oscillations, rising and falling each year. How can this yearly variation of concentration be explained?
8. Challenge: Would you expect the northern hemisphere or the southern hemisphere to show greater oscillations in carbon dioxide? Why?
9. Challenge: In the figure below, notice that methane and carbon dioxide seem to show yearly rises and falls at opposite times. Suggest a reason for these opposite oscillations.

10. In which season would you expect the concentration of atmospheric methane to be the highest?
11. Describe one natural and one anthropogenic source of carbon dioxide, methane, and nitrous oxide.

12. Describe two ways in which increasing carbon dioxide concentrations can cause an increase in temperature.
13. Describe two ways in which increasing temperature may cause an increase in carbon dioxide concentrations.
14. In recent history, temperatures and atmospheric gas concentrations have been measured from air samples. Many of these air samples have been taken monthly from the Mauna Loa Observatory in Hawaii. Considering latitude, temperature, and circulation pattern differences between Hawaii and Antarctica, how might the temperature and atmospheric gas measurements differ between the two data collection sites?

15. In the past 250 years, has the increase in carbon dioxide concentration been linear or exponential? (Hint: Use the slope tool in the Climate Trends learning tool to see if carbon dioxide concentrations increase at a constant rate).
16. Challenge: Following the development of ammonia synthesis by Fritz Haber in 1909, fertilizers could be developed that changed the face of world agricultural practices. Look up this process and use at least 2 chemical equations to demonstrate how it results in the production of nitrous oxide.
17. What is the rate of temperature increase in the last 50 years? 25 years? 10 years? Does this indicate a linear or exponential rate of temperature increase?
18. Challenge: Describe two modern methods of energy generation that release anthropogenic compounds into the atmosphere. Name the anthropogenic compounds that are released. Which areas of the world produce the most of these compounds?
19. Each of the approximately 7 billion humans on Earth exhales about 1kg of carbon dioxide every day. Should we be concerned about human breathing as an increased source of atmospheric carbon dioxide?