Global Warming and Climate Change
A course on science and public policy would hardly be complete without covering global warming and climate change, one of today's most newsworthy and controversial of science and policy topics. Thus, we study the scientific basis behind the idea 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 ideas about the human influence on climate change.
The concept of human-induced global warming refers to the idea that since the beginning of the Industrial Revolution unnatural global warming has been caused by the rapid growth of industrialization and the increased use of fossil fuels, adding excess CO2 to the atmosphere. Global warming and climate change have become very politicized, and there are heated debates regarding the level of certainty that global warming is an urgent problem that society must address. A focal point of these debates is a commonly quoted claim that scientists have come to a "97% consensus" that human activities are the cause of a global warming crisis. Some argue that the percentage of scientists in support of that consensus is only about 80% to 90%, and some say it's much lower. In the politically polarized world we live in, the narrative is often characterized as a battle between those who argue for the higher percentage consensus, trust the science, and advocate that action is urgent, versus others who argue for a lower percentage consensus, are skeptical of the science, and advocate that urgent action is overreacting.
My sense is that the real global warming and public policy story is more complicated than just a battle between these extremes. But regardless, what people decide to believe or not believe about how strong the consensus is, and what to do (or not do) about the problem, is beyond the scope of this course. Consistent with the overall framework of this course, the goals here are:
To learn about the science underlying issues related to global warming and climate change.
To accept that few of us are ever going to be experts on these issues, but that nonetheless there is value in learning as much as we can about the underlying science. A premise of the course is that having this better understanding of the science will make us better able to make informed decisions about global warming and climate change controversies, even if we're not experts.
To be honest and humble in knowing that, unless we are going to pursue a career as a climate science researcher, any decisions we make will likely be based as much on opinion as on fact. Life is uncertain...
The complexity of this topic provides an opportunity to discuss the following fundamental questions, which we return to at various times throughout the course:
How can citizens make informed decisions on science and public policy issues, when we are not experts in the various fields of science that these issues are based on?
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?
As in the case of creation/evolution, students often have very strong opinions on issues associated with global warming and climate change. So, 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.
This is also a convenient 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 explore additional aspects of uncertainty, probability, and statistics below, in particular when we cover the topic of "Earthquakes, the Environment, and Living on an Active Planet."
(More on my thoughts regarding the role of consensus in scientific research can be found here.)