Geoscience Reference
In-Depth Information
12
What of the Future?
Brian Moss
Introduction
Cassandra, the soothsayer of Greek mythology, was given the power to predict
the future accurately by the god Apollo. There was a condition, however, but she
refused to bestow upon him the sexual favours he demanded in return. As
punishment he decreed that she should still be able to predict correctly, but that
no one would believe her. Thus it was that the wooden horse was wheeled into
Troy and the city fell to the Greeks despite her warning. Intellectual endeavour is
about using information from the past and the present to foretell the future as
closely as possible. It inevitably falls short of Cassandra's divine powers in terms
of accuracy, for there are huge elements of complexity, chaos and uncertainty,
especially where matters of environment and human activity meet. But to be even
a little forewarned is to be forearmed, though, like Cassandra's, the predictions
may be scoffed at where they deviate from society's short-term aspirations for its
comfort and convenience.
Predictions of climate change, based on physical models of the Earth's
atmosphere and oceans are now generally accepted and, wisely, degrees of
confidence are stated for them. Confidence is very high that major changes will
occur in the current century, but lower when the details of exact changes in
temperature and precipitation are concerned. Recent data showing that the extent
of melting of the Arctic sea ice in 2007 was greater than anticipated by the most
pessimistic Intergovernmental Panel on Climate Change (IPCC 2007) scenarios
by about 40 years are salutary. The fact that the predictive models are purely
physico-chemical and do not incorporate the effects of positive biological feedback
makes the proposition of major change stronger but the details even more
speculative. It is possible that the effects of warming in increasing respiration rates
in the Earth's ecosystems more than photosynthetic rates will increase the flux of
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