Speaker: Tim Patterson
Carleton University
Topic: The Science and Pseudo-Science of Climate Change: A Geological Perspective
Location: J.L. Gray Centre
Deep River, Ont.
Date: Thursday, June 8, 2000 (8:00 pm)
Tim Patterson

Summary published in North Renfrew Times,
June 21, 2000:

Climate Change Nothing New for Geologists

by Jeremy Whitlock

On Thursday evening, June 8, Prof. Tim Patterson of Carleton University presented "The Science and Pseudoscience of Climate Change: A Geological Perspective" to a capacity audience at the J.L.Gray Centre. The event was co-sponsored by the local branches of the Canadian Nuclear Society and Professional Engineers of Ontario, and marks the final instalment in the CNS' 1999-2000 speaker series.

Prof. Patterson is a geologist who studies the effect of past climatic changes on fish populations, so that we can better predict the future of our fisheries. This work takes him back over thousands of years, during which the earth was sometimes a lot warmer, and sometimes a lot cooler, than it is now.

"The only constant about climate," he says, "is change."

We now know that over thirty separate glaciations have taken place, spread over millions of years. During each of these "ice ages" the planet as a whole becomes cooler and drier, while vast regions stayed ice-covered year-round, much like Antarctica or Greenland today.

Interspersed between these glaciations have been brief periods of warming, before the temperature plummeted again. The cold cycles were brought on by a number of factors, including solar activity, wobbles in the earth's tilt and orbit, changes in aerosol concentration in the atmosphere following events like volcanoes, and (on a much longer scale) continental drift and its effect on both ocean current circulation and mountain building.

Geologists believe that we are currently within one of these temporary warming trends, and will soon (geologically speaking) slip into another ice age. Since the last glaciation 10,000 years ago we have been warming up slowly, with a few hiccups along the way. The most recent "blip" in the temperature rise was a 600-year period known as the "Little Ice Age", ending in the late 19th century.

Prof. Patterson explained how human history chronicles the changing climate over this period, particularly since crop production is correlated with cultural development and even socio-political activity. One event cited was the Viking's colonization of Greenland and Iceland under zero-ice conditions prior to 1000 AD, a situation that changed for the worse only a few hundred years later.

This fascinating perspective laid the foundation for a discussion of the current Climate Change controversy. While pointing out that atmospheric greenhouse gases perform a necessary role, by keeping the earth's average temperature 33 degrees Celsius warmer that it would otherwise be, Prof. Patterson acknowledges that man-made greenhouse-gas emissions have the potential to raise the temperature further.

However, he cautions that it is currently impossible to model all of the complicated mechanisms that interact to produce our climate. Added to this uncertainty is the minor contribution that man-made greenhouse-gas emissions make to the environment. For example, we augment the atmospheric carbon load by less than one percent, and have little idea where a third of that ends up.

Carbon-dioxide levels have been up to 18 times higher at times in the past, and he points out that this isn't necessarily a bad thing since it increases crop production and creates more drought-resistant plants.

Above all, Prof. Patterson wonders if too much is being made of a fluctuation that pales next to the climatic swings reflected in the geological record. There are other valid pollutants, he warns, that may receive less attention because of jaded reaction to the hype over Climate Change. The Kyoto Protocol, he adds, is worthless because it lets countries like China continue to burn fossil fuels, while the West deindustiralizes.

For those who missed the talk or seek additional information, Prof. Patterson's material is available in the form of a "virtual" course at his Carleton University webpage: http://www.carleton.ca/~tpatters.