Global Warming Science

Syllabus

Course Meeting Times

Lectures: 2 sessions / week, 1.5 hours / session

Prerequisites

Physics I (8.01), Calculus I (18.01)

Corequisite

Thermodynamics and Kinetics (5.60)

Course Description

This course provides students with a scientific foundation of anthropogenic climate change and an introduction to climate models. It focuses on fundamental physical processes that shape climate (e.g. solar variability, orbital mechanics, greenhouse gases, atmospheric and oceanic circulation, and volcanic and soil aerosols) and on evidence for past and present climate change. During the course they discuss material consequences of climate change, including sea level change, variations in precipitation, vegetation, storminess, and the incidence of disease. This course also examines the science behind mitigation and adaptation proposals.

Further Background

This course focuses on the science of climate and climate change, giving students a broad background in the central concepts and tools of climate science. For example, while nearly everyone has heard of the “greenhouse effect”, we will go into some depth on the issue of radiative transfer through gases. We will address such questions as

• What is climate?
• What physical, chemical, and biological processes control climate?
• How has earth’s climate varied since the formation of the planet, and why?
• How has climate been varying on human time scales, and why?
• How might climate change in the future?

In addition, we will endeavor to acquaint students with the primary tools which climate scientists use to understand and predict climate. As part of this endeavor, we will use develop and use a hierarchy of models of the climate system, ranging from simple toy models that can be solved analytically to one-dimensional climate models that solve comprehensive equations of radiative and convective heat transfer. Problem sets, issues approximately biweekly, will help develop an understanding of climate science, and a term projects will address some of the pressing issues on climate science today.

Textbooks

A general, mostly qualitative background to climate science is provided by Archer, David. Global Warming: Understanding the Forecast. Wiley, 2011. ISBN: 9780470943410. [Preview with Google Books]

A good summary of the state of understanding of global warming can be found in Climate Change 2007—The Physical Science Basis: Working Group I Contribution to the Fourth Assessment Report of the IPCC. Cambridge University Press, 2007. ISBN: 9780521880091.

Class Participation

This is a discussion-based and problem solving-based class. Some of the class time will be spent solving problems in small groups or in class discussion.

Grading

About 60% of the course will be based on problem sets, 40% on the term Project, and also partly based on participation in class discussion.

Term Project

Term project should address an interesting and perhaps controversial issue in climate science, and be of order 10–20 pages in length. Students were asked to summarize their project in a 10-minute presentation to the class toward the end of the semester. Each student selects a topic for the project. For example, they could address the validity of the following controversial statements that are often found in popular literature:

1. Water vapor is by far the most important greenhouse gas in our atmosphere. Thus variations in other greenhouse gases, such as CO₂, are irrelevant.
2. Solar variability accounts for much of the climate change that occurred over the past 1000 years also accounts for most of the warming of the last 150 years.
3. Global mean temperature peaked in 1998 and has been lower since then. Thus the idea that the earth is warming is a myth.
4. Although CO₂ and temperature are strongly correlated during the great glacial cycles, as revealed by ice core data, most evidence indicates that CO₂ follows temperature, so temperature changes cause CO₂ changes, not the other way around.
5. Changes in cloudiness counteract the direct effects of CO₂—induced warming.
6. Most of the observed increase in CO₂ was caused by volcanoes.
7. Mars is warming too.
8. The globe failed to warm, and the northern hemisphere actually cooled, from around 1950 to around 1980, a period during which the concentrations of CO₂ and other greenhouse gases increased. So increasing greenhouse gases cannot cause warming.
9. It was warmer during the medieval warm period than it is today.
10. Since we can’t predict what the weather will be doing 10 days from now, there is no way to predict climate change.