Now for something completely different: a dispassionate analysis of what we actually know and what we don’t yet know about climate change. In this class, Professor David Helfand carefully distinguishes facts from fiction, and physics certainties from feedback uncertainties. For few issues is the public debate conducted with so much misinformation, especially with regard to such an important issue that affects everyone, everywhere.
Every planet’s temperature is controlled by a simple balance between the energy it receives and the energy it radiates back into space. We will examine each of the main factors affecting this balance, and begin by exploring the astronomical phenomena that have driven climate change in the past: solar variability, changes in the Earth’s orbit and other factors over which we have absolutely no control. Professor Helfand will then go on to show how the composition of the Earth’s atmosphere has changed in the past and is changing today using measurements of prehistoric climate derived from tree rings and ice cores. Examining the current energy balance and what we can expect over the next few decades, we will conclude by discussing what is actually true (including the good, bad, and very bad) explode a few myths, and provide a rational basis for decisions about our future.
David Helfand has been a Professor of Astronomy at Columbia University for over 40 years, where he has served as chair of the Department. He is also the former President of the American Astronomical Society and of Quest University Canada. Professor Helfand has received the Columbia Presidential Teaching Award and the Great Teacher Award from the Society of Columbia Graduates. He is the author of A Survival Guide to the Misinformation Age: Scientific Habits of Mind.