Global Climate Change Committee

A worldwide debate is occurring on the topic of climate change; commonly referred to as “global warming”. This debate seems to focus on three questions: Is “global warming” really happening? If so, is human activity a cause? Finally what can be done about it? A quick review of articles in the popular press might lead one to the conclusion the debate has already finished. There are profound implications to the outcome of this debate. Political and economic impacts arising from this debate will effect all our lives and do so significantly.
My musings and my reason for writing this article arise from a concern. I perceive this debate is occurring outside the context of basic knowledge about the Earth’s history!
The concepts that the earth’s climate changes and that sea level rises and falls, often seem new to nongeoscientists that I have talked to. The general public believes, I’m afraid, that rising sea level, as a possible future event, is a newly identified phenomenon revealed by Newsweek, Time and CNN! In contrast, for geoscientists these concepts are commonly accepted knowledge, indeed, basic in the day-to-day work of correlating strata, well logs and seismic reflections using the principles of sequence stratigraphy, paleontology, biostratigraphy and paleoecology.
As a geologist, I am often surprised at the response when I mention the most basic concepts of earth history to non-geoscientists. Carl Sagan coined a term, “demons in the darkness”, in which he referred to the power of myth, pseudo-science and ignorance in our culture. A survey, cited by AAPG President Marlan Downey, in his address at the opening ceremony of the 2001 Denver AAPG Convention revealed that most Americans would rather attend a lecture on astrology than one on astronomy. I submit that debating “global warming” outside the framework of basic historical geologic knowledge is akin to allowing the “demon” of ignorance into the public policy arena, perhaps unintentionally, but hazardous for correct conclusions. I feel strongly that we as geoscientists have to get more involved in discussions with our own acquaintances outside our profession about the global warming debate. We owe it to our society to find ways to express the range of Earth’s climate variations throughout geologic time in ways our non-geoscience friends can understand, in order to give them perspective on the debate. Such discussions can take place anywhere, at the soccer field, the golf course or the cocktail party. I would like to share one of my most effective anecdotes for discussion of “global warming” here, hopefully to encourage you to help in the crusade to inject some basic earth history information into people’s perspective as the debate goes on. I hope you agree! My anecdote involves a lesson I draw from geologic observations in two of the most spectacular places on earth, the Grand Teton mountain range of western Wyoming and southern Greenland. Places which have dramatic scenery and obvious differences, or, are they really so different?
I have been a student of the Grand Teton mountain range ( Figure 1 ), south of Yellowstone National Park in western Wyoming, since my first visit during undergraduate years in college. One’s appreciation of the Tetons increases with understanding of the natural processes, which have created its imposing beauty. The key geologic process, which has sculpted these granite peaks, is, erosion by glaciers! In fact, the Teton range is a world-class example of alpine glaciation, slow moving “rivers” of ice formed at high altitude, which flow slowly down slope with such enormous force they cut and shape solid rock. The remnants of the Teton glaciers still exist at high altitude. They can be visited, touched, and used as a water supply for hikers and climbers. When did sufficient ice exist in Wyoming to cause this amazing landscape to form? Geologic evidence, including dating of shells buried in the glacial outwash, indicates massive glacial activity peaked 25,000 years ago and ended only about 12,000 years ago, yesterday in geologic time! In fact, classic geologic studies tell us the Pleistocene epoch, about the last two million years, was a time of repeating cycles of glacier formation, with advance and retreat leaving ridges of gravel, sand and silt at the foot of each canyon which trap spring water to form the beautiful lakes, such as Jenny Lake, at the foot of each canyon. There is evidence that ice existed on the valley floor of Jackson Hole as recently as 9,000 years ago.
Now I turn the conversation to a place where large active continental glaciers can be seen today, southern Greenland. Here actively flowing glaciers move to the sea, eroding the bedrock. The mountains of Greenland protrude through the ice sheets, often looking like islands caught between rivers of ice ( Figure 2 ). The canyons being formed today in Greenland would look like the exposed valleys in the Grand Teton range if they were ever exposed. The point of all this is to illustrate, I hope clearly and dramatically, that only a few thousand years ago, Wyoming looked like Greenland does today. What caused the Wyoming ice sheets to melt? Certainly not CO2 from fossil fuels, unless the mammoths were driving cars!
Anthropologists study the impact of climate cycles on the migration of Paleo-Indian people across the Aleutian land bridge. This bridge was formed as sea level dropped because so much water was being converted to massive glacial ice sheets. Fascinating accounts of this are detailed in National Geographic articles such as the October 1998 issue’s “The Peopling of the Earth”.
In fact, today’s geoscientists, in both the academic and industrial worlds use a standardized reference scale of worldwide sea-level rise and fall, with sea level changing hundreds of feet periodically over the last few million years. This calibrated cyclic change in global sea level resulted as the volume of glacial ice varied. As the climate cooled, more ice formed and less water remained in the oceans, as warm weather melted ice, more water moved to the oceans causing a rise in sea level. The cyclical changes in sea level have occurred repeatedly over the last million years and are a one of the key processes in sequence stratigraphic models, which are employed by geologists in many applications, notably petroleum exploration.
My point?
It has been occurring in carefully documented cycles for tens of millions of years. Today, we are about 25,000 years into a warming cycle, which by all past evidence will be followed by cooling. Yes, strange as it seems, our beloved national parks could again be the sites of thousands of feet of ice like they were only yesterday in geologic time! The beautiful scenery of the present day mountains of Wyoming resulted from the past action of glaciers. The same processes, which are the key to understanding Wyoming’s past, are happening today in Greenland, a beautiful example of the 19th century insights of pioneering geologists.
So, is there a global climate change? YES
Is this period we live in, a warming period? YES
What causes these dramatic cycles?Many causes are possible including cycles of solar energy output, changing climate as continents change position and atmospheric and oceanic circulation changes. We’re not sure but scientific research continues.
Could human activity, such as a carbon dioxide release from fossil fuel burning be the cause?Possible, but the industrial revolution began only 150 years ago! Human activity cannot explain everything. Tens of thousands of years in the final cycle of the current warming phase are unexplained if burning fossil fuel is the cause.
Is the concept of sea level rise or global warming a brand new phenomenon never before experienced on ou