Climate Change and the Return of the Ice

The term "Ice Age" is an odd one. We think of it as the time when great ice sheets advanced southward from the polar region. In the context of Earth history, however, we have been in an ice age for the last ~3 million years. Antarctica and Greenland are still in an "ice age" today. This broader definition of ice age is punctuated by relatively brief interglacial periods. All of our societal history has taken place during the current interglacial period. Humans have no written record from the last time the ice advanced.

It is my contention that the climate change we are currently experiencing could precipitate a premature end to our current interglacial period. I present this qualitative model to explain how this could happen very quickly and very soon.

I am not a climate modeler. I'm not even a person who studies ice ages. Most of my field research deals with sediment shed off of the Andes in Argentina and Bolivia. My primary professional task is to be a good teacher. Ever since I received my Ph.D., in 1987, I have been affiliated with small Geology programs. As a result, I have taught a wide variety of courses across the spectrum of the Geosciences. Nothing presented here is anything that students aren't exposed to in introductory geology courses such as Physical Geology, Historical Geology, and Physical Oceanography, although all of these facets are usually not taught in any single course.

My first exposure to this problem occurred in the Physical Geology course I took as a Dartmouth freshmen, in the winter of 1972. It was taught by Geophysicist Bob Decker and Glaciologist Willie Weeks. I don't remember who came to the conclusion that in order to have an ice age, the Arctic Ocean had to melt. I found that conclusion to be interesting but in my adolescent naiveté I couldn't fathom how the Arctic Ocean could possibly melt. Now, several decades later, there is substantial evidence that Arctic Ocean sea ice is melting at a frighteningly fast rate due to the rise in global temperatures.

I began to look into the possibility of a glacial readvance occurring. I compiled the ideas of others and drew my own conclusions. There are quite a few really bright people who are interested in this problem and a lot of modeling has been done. It is interesting that Hollywood came out with a disaster movie, "The Day After Tomorrow", that is loosely based on these ideas.

Interestingly, some people in pretty high places, particularly the Pentagon, NASA, and the Woods Hole Oceanographic Institution, are extremely concerned with the possibility of a dramatic climatic shift in the near future. When I first read these reports, they really scared me. I sat down to figure out how they could possibly be true. To my chagrin, all of the evidence was already in place in my brain but I'd never put it together. The linked presentation,  below, attempts to explain, in layman's terms, how we could be plunged into a new cycle of global cooling or possibly even a new ice age within a few decades.

The final screen presents links to some other important websites on this topic. If such an event comes to pass, it will affect everyone on Earth. My major concern is that few people are aware of the possibility of a dramatic climatic change taking place within their own, or at least their children's, lifetime. Most of these sites refer to abundant paleontological evidence to substantiate that such changes have taken place in the fairly recent past. A growing number of scientists are deeply concerned about this possibility. You should be too.

Making you aware of this danger is the impetus for the slide show you will see after you click below. This is the annotated version of my public presentation which I seem to be giving more and more each semester. I have tried to break it down to the basic information that is needed to understand how such a change could happen. To view online, you will need to use MS Explorer or any other browser that supports the Power Point web format.

Climate Change and the Return of the Ice

The base maps used in this presentation were generated using an excellent website that allows the user to generate a map in almost any projection during the last 150 million years. Take a look at it at: http://www.odsn.de/odsn/services/paleomap/paleomap.html .