December 30, 1999: Canada is a signatory to the 1997 Kyoto international treaty on Greenhouse gas emissions reductions. Greenhouse gases trap heat that would otherwise be radiated from the earth into space. Greenhouse gases thus play a central role in regulating the global energy balance and, hence, global climate.
The principal greenhouse gases in earth's atmosphere are water vapor, carbon dioxide and methane. Fossil fuel combustion during the last 150 years has raised atmospheric carbon dioxide concentrations from around 250 parts per million in 1850 to 350 million parts per million today (1). The rate of increase in atmospheric carbon dioxide concentration has accelerated in the last half century and, if present trends continue, there will be an approximate doubling of concentration in the next half century. The environmental consequences are uncertain and hotly debated. There are, however, plausible reasons to fear that a continued build-up in atmospheric carbon dioxide concentration will result in substantial climatic warming with possibly disastrous consequences such as a rise in sea level that would flood most of the earth's habitable land (2), or a change in ocean currents that could precipitate a new ice age (3).
These dire possibilities notwithstanding, a December 30, 1999 National Post article indicates that Canadians have done little about the problem, expect to do little about problem and wish to do little about the problem. Since the signing of the Kyoto treaty two years ago, Canada's carbon dioxide emissions have increased, not decreased and now stand 13% above those of 1990. Further, according to opinion surveys conmissioned last year by Environment Canada, Canadians ranked global warming 12th behind 11 other environmental concerns including air and water pollution, deforestation, ozone layer depletion and toxic waste. Moreover, Canadians ranked environmental concerns generally far behind the issues of health care, unemployment, national unity, and taxes.
The Government of Canada, however, is not inactive in pursuit of a strategy to meet
its Kyoto commitment. According to a December 28, 1999 National Post story,
research by the Federal Government has examined the implications of redefining the
word "forest" in such a way that Canada is credited under the terms of the Kyoto agreement with
carbon dioxide absorbed by trees planted after the logging of mature timber. The political logic
behind this thinking is clear. Unfortunately, it makes no environmental sense, because although
trees planted on logged areas absorb carbon dioxide, this represents merely the
recapture of carbon released to the atmosphere as a consequence of removing the pre-existing
forest. Thus the net impact on atmospheric carbon dioxide concentration of timber harvesting
followed by tree planting is, after a hundred years or so, almost exactly zero.
(1) Encyclopaedia Britannica. Atmosphere: Increase in carbon dioxide concentration. (2) naturalSCIENCE Cover Story, November 1, 1997. A new European ice age?. (3) Trenberth, Kevin, E. naturalSCIENCE article, December 4, 1999. Global warming: It's happening.
(1) Encyclopaedia Britannica. Atmosphere: Increase in carbon dioxide concentration.
(2) naturalSCIENCE Cover Story, November 1, 1997. A new European ice age?.
(3) Trenberth, Kevin, E. naturalSCIENCE article, December 4, 1999. Global warming: It's happening.