Revisiting the canary in the coal mine.

• Author: Ayres, Ed
• Position: Note from a World Watcher - Environmental issues

The environmental movement is now old enough to have a real history, as outlined in the chronology on pages 30-35 of this issue. In the course of that history, we have experienced some momentous changes, both in our understanding of the threats we face and in how we are responding to them. In the early years, the ozone hole was known to be a major threat, for example, whereas global warming had not even entered our consciousness. Today, the ozone-hole problem has at least begun to stabilize, but global warming has become a looming danger. As suggested by the guest editorial on page 2, it may pose a far larger threat than that of terrorism.

As our environmental perceptions have changed, so have our means of quantifying and communicating them. In the 1970s and 80s, much consciousness-raising played on sentimental and emotional hooks--concern about the decline of whales, wolves, and other charismatic mammals, or the heart-wrenching tragedies of Bhopal or Love Canal. Now, the biggest news is being generated by dispassionate climate models and lab studies of obscure microorganisms--and by hard analysis of a global economy that has enriched many but left many more in a state of untenable discontent.

Our language, too, has changed. Some of the metaphors that made sense a quarter-century ago are now dated. One of the popular metaphors of the early environmental activists was that of the canary in the coal mine--based on the 19th-century British coal miners' practice of taking a caged bird into a coal mine to serve as an early warning of accumulating methane or ethylene gas. If the canary flopped over, it was time for the miners to get out fast. Later, the capitulating canary came to be a useful symbol of impending ecological collapse. Just as miners who wished to survive needed to beware the asphyxiation of their birds, humanity at large needed to beware the dying of forests and eutrophication of lakes.

Eight years ago, this magazine published an article on the global decline of birds. At the time, we thought it quite appropriate to invoke the canary-in-the-coal-mine metaphor. If thousands of avian species were endangered by human activities, it was as though the whole Earth had become one vast coal mine. Coal, of course, was a big part of the threat literally as well as metaphorically; it was the largest source of global warming gases and acid rain, and a major source of urban smog. For this issue, we decided to update that 1994 story. As we began...