A course on science and public policy would hardly be complete without covering global warming and climate change, probably today's most newsworthy and controversial science and policy topics. Thus, we study why scientists have concluded that the Earth's atmosphere has been getting warmer since the late 1800s. This requires a thorough explanation of the Earth's atmosphere and how electromagnetic radiation from the sun interacts with the atmosphere to warm the environment near the surface of the Earth. Considerable amount of lecture time is spent exploring the nature of light and electromagnetic radiation to provide a thorough understanding of the "greenhouse effect" and the human influence on climate change.
As in the case of creation/evolution, students often have very strong opinions on this matter, and similar care must be taken to respect their diverse political views and keep true to the promise that nothing in this course is intended to be an endorsement of any particular political opinion. The focus should be on scientific rigor, on understanding the underlying scientific concepts, and on enabling an informed discussion of how this scientific background needs to be considered as part of the process of making policy decisions. The current consensus among climate scientists is that increased global warming is caused by the rapid growth of industrialization and the increased use of fossil fuels, adding great quantities of carbon dioxide to the atmosphere. This all leads to strong opinions about what is the right policy to pursue, and necessitates a clear explanation of what it means that scientists have come to a "consensus" on this (and other) matters.
This part of the course explores questions such as: In cases where the scientific basis of a public policy issue is ambiguous, when is it appropriate to take political action? What constitutes sufficient evidence that political action should be taken? When is it justified to spend money for additional research to investigate the scientific basis of a public policy decision?
This is also an effective time in the course to explore how scientists and public policy makers use the concepts of probability and statistics in the decision making process. Scientific results related to public policy issues are, of course, subject to uncertainty, and are often stated in terms of probability and statistics, so some background in those topics is necessary. We return to uncertainty, probability, and statistics again when we next cover the topic of "Earthquakes and the Environment."