What post-2012 forestry policy for NZ?

Authors: Piers Maclaren
Publication: New Zealand Journal of Forestry, Volume N.Z.J.For. 2007, Issue N.Z.J.For. 52(3) 2007, pp 48, Nov 2007
Publisher: New Zealand Institute of Forestry

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Abstract: [First paragraphs ...]
“Nah, I don’t believe in global warming. For example, take the 10-year old Eucalypt in my garden. It was killed by last winter’s frost. If Global Warming exists, why didn’t it happen before?”

I have heard versions of this argument depressingly often. It contains four basic misconceptions, but may lead to some psychological insights. The first error is to assume that one’s own amateur observations are valid data points, comparable to the measurements of a specialist. The unfortunate eucalypt could have died as a result of air-ponding caused by the neighbour’s new garage, for heaven’s sake.

The second is to assume that local events can be extrapolated to the whole world. Furthermore, Global Circulation Models suggest that there will be entire regions larger than New Zealand where the short-term consequences will be a cooler climate.

The third difficulty is another confusion of scale. Why do people find it so hard to appreciate the importance of a relevant timescale? (One person told me that Global Warming was no cause for concern: after all, the Earth had been molten rock four billion years ago!) One cannot expect a continuous smooth trend. Ten years is too short an interval on which to judge or react to human-induced Climate Change, and for that matter a thousand years is far too long. The IPCC has focussed on 100 years as being a more appropriate human timeframe.

Fourthly, a popular but erroneous opinion is that the whole theory of global warming was derived from temperature observations. In fact, international concern arose because of the increase in atmospheric carbon dioxide that had been observed since 1957 - plus the well-known behaviour of that gas. The International Framework Convention on Climate Change was formulated by the start of the 1990s, although warming became statistically significant only after another decade. Temperature measurements are merely the validation of the theory, not its justification.

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