Friday, April 09, 1999 Hot enough for you?
Dr. Tim Patterson and Tom Harris
National Post
David Suzuki's new film, Turning Down the Heat, was aired on CBC-TV last night. This government-sponsored video explains how alternative, non-fossil fuel technologies can provide solutions to what Dr. Suzuki calls "the greatest threat to humanity in the modern era" -- the climate crisis.
Despite Dr. Suzuki's promise that "this [film] will leave you inspired and optimistic about a cleaner, healthier future," he has done little more than scare Canadians unnecessarily. Telling us the build-up of greenhouse gases as caused by our burning of fossil fuels will result in an environmental catastrophe is hardly responsible citizenry when so much evidence exists to the contrary.
Suzuki seems to be relying far too much on predictions made by global warming theorists who work with computer models of the future but use little actual data. With the support of biologists, who generally lack a proper understanding of long-term climate dynamics, environmental groups, mass media and government have treated these theoretical scenarios as credible indicators of future environmental change.
Yet, predicting the future of Earth's climate by computer models alone is risky. Because the earliest simulations of climate change did not take many variables into consideration -- they did not even consider the influence of ocean circulation -- temperature changes as great as eight degrees were forecast over the next century.
As more variables were incorporated into the models, the amount of predicted change has decreased. However, even today's models cannot recreate past known climatic conditions or predict the present without fudging the numbers. Dr. Wallace Broecker, a renowned Columbia University oceanographer/climatologist, believes more than one million variables influence climate change. Although not all are required to reasonably model climate, this underlines why computer simulations are not very accurate. Are we, as a society, to base major policy decisions on such faulty models?
By contrast, Earth scientists rely more on empirical data recorded in thousands of peer-reviewed scientific papers. One of the best tools we have to predict the future is the well-documented geologic record of both gradual and rapid climate changes in the past. These records reveal that, for more than 90% of Earth's history, conditions were much warmer than today. Two million years ago forests extended nearly to the North Pole. As recently as 100,000 years ago, temperatures were high enough that hippopotami and other animals now found only in Africa, made their homes in northern Europe.
Over the past 1.6 million years, however, it has generally been much cooler than this, with periodic rapid fluctuations from cooler to warmer intervals known as interglaciations. The causes of these dramatic climate variations include continental drift, changes in ocean/atmospheric circulation, natural wobbles in the Earth's orbit, and variations in solar energy.
Despite a 0.6-degree warming that has occurred over the past century (most of which was in the early 1900s before worldwide industrialization and the period of greatest carbon dioxide buildup), overall, temperatures have dropped about three degrees in the past 5,000 years. Whether short-term global warming is occurring or not (the data are not clear), another ice age will definitely begin within the next few thousand years. While this is no excuse for continuing to foul our own nest, a gradual greenhouse gas buildup may be a blessing, something that could delay the onset of the next glacial period, or at least reduce its severity.
This is an issue environmental groups need to be more honest about. Dr. Suzuki confidently asserts that "An increased rate of global warming would have serious negative impacts on the health and welfare of humans . . ." Perhaps, but the historical record certainly does not indicate this. The demise of Greenland's Viking colonies provides an instructive example.
When Erik the Red was exiled from Iceland for murder in 980 AD, he was fortunate that his banishment coincided with an unusually warm climatic period. Open sea-lanes allowed him to make his way to a reasonably hospitable land. Christening the island "Greenland" was not merely a gimmick to attract Norse settlers. The pioneers who followed Erik had a reasonable prospect of prosperity in this new world. They raised sheep and cattle brought with them from Iceland and even grew grain.
About 1350, however, the weather began to turn bad (this is where the "warmest in 600 years" headlines came from this summer). Crops failed and the settlers became increasingly dependent on supplies shipped in from Europe. As the climate continued to cool, sea ice started to restrict shipping. By the 15th century, the colonists were cut off from the outside world.
Recent archaeological evidence shows a pathetic end to the Vikings' most westerly outpost. With the ground frozen throughout most, and finally all, of the year, famine-weakened Norsemen eventually could not even properly bury their own dead. The "Little Ice Age" had begun and the Greenland settlements were wiped out as effectively as the Viking themselves had reduced many a European coastal town to ashes.
With a 1.5-degree drop in average temperature over the next hundred years, Iceland and Eastern Europe were nearly depopulated and famines periodically ravaged much of Western Europe. Ice caps began to develop in the Arctic, and glaciers advanced throughout the Alps.
Little Ice Age cooling was global in extent, with evidence also found in western North America from Alaska into the continental U.S., China, the Andes Mountains, New Zealand, and even in equatorial Kenya.
Wildly erratic and frigid conditions continued until the mid-19th century, when skating parties on the Thames River in England finally had to be abandoned as conditions gradually warmed up to those of the mid-1300s. Nonetheless, the 10th century, when Eric the Red settled Greenland, was still one degree warmer than the 20th century. This is worth remembering when reading alarmist "warmest in 600 years" headlines.
While the Little Ice Age was undoubtedly harsh, it may prove to be minor compared with what may be in store for us if our climate follows past trends, as expected. In the past 1.6 million years, there have been more than 30 glacial advances and retreats. It was only 10 millennia ago -- when humans were fashioning flint spearheads to hunt the last woolly bison and carving flint sickles to work our first farms -- that ice sheets, some up to a mile thick, finally retreated from Europe and North America.
We have to wonder whether the global warming concerns of the past two decades have been overblown. Is the warming since the late 19th century due to natural oscillations, well recorded throughout geologic history, or is it due to industrialization? Since current conditions are only slightly warmer than those at the end of the last major ice age, were we saved from glacial devastation by industrialization?
No one knows the answers to these questions. What we do know is that the next glaciation, due within a few thousand years, is part of a natural climate cycle that will continue for at least several million years. The nature of our planet's orbital dynamics and position of the continents as they influence ocean circulation are the main controls, not human activities.
Based on the impact of the 1350-1880 Little Ice Age, it is apparent that humankind, and particularly Canadians, benefit much more from warmer climate than cooler. Viewers of Turning Down the Heat need to remember this while being told about "the urgent need to face the growing threat to the environment, climate stability and human health posed by increased global warming." (as quoted from Dr. Suzuki's Web page). Such statements can only be classified as sensationalism until we know much more than we currently do about our planet's atmosphere.
To move full speed ahead with draconian cuts in greenhouse gas emissions, as advocated by Dr. Suzuki and other environmentalists, would be a recipe for economic disaster for all Canadians.
Tim Patterson is Associate Professor of Earth Sciences at Carleton University in Ottawa. Tom Harris is an Ottawa-based freelance writer.
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