"Global warming is unlikely to be entirely due to natural causes and that a pattern of climatic response to human activities is identifiable in the climatological record".
This statement issued by the Intergovernmental Panel on Climate Change, a United Nations Panel to the Climate Change Convention, may finally end a long standing debate that humans are a causative factor in modifying the earth's climate. In their report, the Panel forecasts an increase in average global temperatures of 1.44°F to 6.5°F by 2100 if no actions are taken to curb greenhouse gases, notably carbon dioxide. Have we reached the point in history where human influences now stand to modify evolution itself? Have we reached the "End of Nature"? That is the question I wish to address in this column.
Is the above statement by the Intergovernmental Panel on Climate Change proof that global warming is actually happening? Ask this question to an average Albertan who has endured two below average temperature summers over the last three years and you'll undoubtedly get a look of disbelief. But continued advances in "super" computing technology and our ability to model complex weather patterns in our atmosphere now indicate this is the case. Still for many of us, the real question is "so what"!
In his book, The End of Nature, Bill McKibben writes that we are finally seeing the end of nature and that humans have become such a dominant force on this planet that we are finally influencing the very nature of climate and the atmosphere itself. He argues we are in fact controlling (although some will say we are out of control) the very essence of nature itself1.
A decade ago, it was hard to get anyone interested in either global warming or ozone holes. Yet the evidence is now overwhelming. The earth is getting warmer and ozone holes at both the North and South Poles continue to enlarge (although they have shown some fluctuations). Despite Calgary's cold wave in the summer of 1995, summer temperatures across Canada tied for the third warmest this century, behind 1989 and 1994.
The phenomenon of global warming was first noted by the Swedish scientist, Svante Arrhenius who noted increases in carbon dioxide levels following the industrial revolution. He reasoned that if carbon dioxide concentrations doubled, the temperature of the earth would increase several degrees. Since the Industrial Revolution, global carbon dioxide concentrations have increased 28%(from 280-365 ppm) and the earth's global mean temperature has shown an increase of 0.5°C. However, this temperature increase has not been gradual but has been marked by a series of increases and decreases2. Now a study by Karl and Kukla suggests that global warming may not be a global phenomenon. These two scientists postulate that global warming is in fact happening at night and we are seeing a decrease in the range between daytime and nighttime temperatures3. Global warming may actually have some benefits to agriculture by reducing the frequency of killing frosts.
In addition to "global warming", natural disasters too are on the increase. Are these two phenomena related? The UN reports that over the last 30 years, the number of disasters has increased 6% per year. From 1963-1967, there were 89 reported disasters which caused more than 100 deaths; from 1988-1992 there were 205. The report indicates this is in part due to increased urbanization, large scale habitat changes through agriculture and deforestation, and the result of global warming4.
And is ozone depletion an issue ahead of unemployment and the Quebec referendum in the polls? I hardly think so, yet even today there is still misinformation about the threat posed by CFC's, or ozone destroying chemicals. Recently the Calgary Herald featured a letter from a representative of the Canadian Aerosol Information Bureau who reassured us that aerosols do not pose a grave danger to the environment and that chlorofluorohydrocarbons (or CFC's) have been banned in Canada since 1988. The truth, in the case of ozone depletion and CFC's, is that the damage has already been done. None of the General Motors chemist's who invented CFC's in 1928 would ever have dreamed they could be an environmental threat? And yet the two major CFC's (CFC11 and CFC12) which have been produced for use in air conditioners, refrigerators, aerosol sprays and those styrofoam coffee cups (even though no longer in use), once in the atmosphere may not break down for a 100 years. Atmospheric scientists now estimate that the ozone layer will start to repair itself, but not until after 2050.
Another sign that perhaps we have reached the end of nature, is that we may have reached the end of evolution of the world's species (ourselves included). Hard to believe, but it is now thought we have curtailed the opportunities for evolution of larger mammals (for example grizzly bears, lions, elephants, etc.) by reducing the size of breeding populations through restrictions to their habitat and movements. Some breeding populations are so small that extinction is now a real threat.
An example of this close to home comes from a report by Mike Gibeau describing the preliminary results of the Eastern Slopes Grizzly Bear Research Program underway at The University of Calgary5. DNA analysis from bears captured in the Bow Valley Watershed indicates that there is little gene flow occurring between Rocky Mountain grizzly populations and those further south. This phenomenon of reduction in genetic diversity is termed a "genetic bottleneck". Gibeau suggests that possible factors implicated in this genetic bottleneck may be transportation corridors, which limit bear movements, and human induced mortality. The long term implications of this reduction in genetic diversity are unknown, but Gibeau cautions that we should be more concerned with immediate threats to grizzly populations such as excessive mortality before dealing with longer term issues of genetic health.
And the worldwide extinction rate of species continues to rise at an unprecedented rate. Since 1700 about 50 mammal species and 70 bird species have gone extinct6. A rate greater than that of the last great dinosaur extinction. Since the arrival of Europeans to Canada, at least 20 species of plants and animals have gone extinct. Today we have 56 endangered species and 187 more that will likely become endangered in the future, unless steps are taken to protect them7.
What about human evolution itself, have we evolved beyond nature? In his highly acclaimed 1975 book, Sociobiology, E.O. Wilson drew the ire of his critics by proclaiming humans were evolving differently from other species on the planet due to what he termed "autocatalysis" or the combination of genetic and cultural factors that have taken us beyond the dictates of natural selection. And while other species decline on Earth, our population continues to grow unabated, although world population growth has declined from 2.5% in 1965-1970 to 1.7%. Even so, the current population is over 5 billion and growing at 93 million per year8. And we continue to see a shift toward becoming more of an urban rather than rural society. By 2030, urban populations will be twice the size of rural populations, increasing our susceptibility to natural disasters such as earthquakes, as mentioned earlier. As we become more and more urbanized, does the importance of nature in our daily lives also become diminished?
The point of this column is not to debate whether global warming is happening and what that may mean in future. Nor can I, in the few words available, provide extensive comment on some of the ideas presented here. Rather, I want to present the opinion that we have truly reached the end of nature. Our species has become a measurable force determining the future of evolution on this planet. And we are the only species on Earth with this capability. We can no longer marvel at the "power of nature" and no longer engage in activities that pit "man against nature". Rather, we now have a responsibility to govern our acts accordingly and consider the consequences of our actions. Let us hope that with this increased responsibility comes increased awareness, for if we have truly reached the end of nature can we live without it?
1 McKibben. B. 1989. The End of Nature. Anchor Books. Doubleday. New York.
2 I searched the Internet under 'global warming' and found a number of web sites. This one refers to Global Warming. NASA facts (at NASA's home page).
3 New Aspect of Global Warming Discussed at International Conference. The Earth Observer - September/October 1993.
4 Article in Calgary Herald, October II, 1995.
5 Gibeau, M. 1995. Implications of preliminary genetic findings for grizzly bear conservation in the central Canadian Rockies. Eastern Slopes Grizzly Bear Project Report. 1995.
6 World Development Report 1992. Development and the Environment. Published for the World Bank. Oxford University Press.
7 Species in Peril. Environment Views. Summer 1995.
8 World Development Report 1992.