Implications of Flips for indicator development

James J. Kay

Incremental external change (pollution etc.) may not result in incremental change in an ecosystem. In fact it may appear that there has been no effect on the ecosystem. So no problem may be perceived. However if a threshold is reached, a small external change may cause dramatic ecosystem change. And then it is too late.

Ecosystems are organized about attractors. There are maintained at attractors by feedback loops. Feedback loops cannot be explained by linear cause and effect relationships, that is the traditional mechanical explanations that we use. This is because in a feedback loop the effect is part of the cause.

It now appears that flips, as versus slow continuous change, are quite normal in nature. It seems that the global climate system behaves this way as well. There is evidence of 8 flips, changes of mean temperature of 10C in less than a decade. It appears that 15,000 years ago there was an increase of 16C in a couple of decades. (J. P. Severinghaus, E. J. Brook, Abrupt Climate Change at the End of the Last Glacial Period Inferred from Trapped Air in Polar Ice, Science, Volume 286, Number 5441 Issue of 29 Oct 1999, pp. 930 - 934)

The existence of more than one possible attractor in a given situation means that there may not be an ecologically preferred state for the system.

Updated 27 December, 1999

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