Introduction - Climate Change Impacts on Freshwater Ecosystems - page 3

Figure 1.2 (a) G.E. Hutchinson and (b) James Lovelock.
Changing ideas on planetary function
Ecologists have long sought to explain the huge variation of natural systems: the
tapestry of weather and soil-related detail on land and physical and chemical
detail in water that fits into a grand pattern of climate zones. G.E. Hutchinson
(1965) (Fig. 1.2) linked the ways that organisms evolve, as both grand and local
patterns change, in his metaphor of the ecological (or environmental) theatre and
the evolutionary play. His concept, in the 1960s, was very much one of the
players adjusting to the nature of the theatre and then to each other. The generally
accepted paradigm was that the physicochemical setting, the geology and climate,
determined the biology and ecology of living organisms. Twenty years later,
James Lovelock (1988) (Fig. 1.2) began an overturning of this by a spectroscopic
examination of the chemistry of the atmospheres of Earth and its sister planets
and a study of Earth's oceans. He calculated that the chemical state of Earth was
very far from that expected by a simple chemical equilibrium of the available
elements, and inferred that it was determined, and maintained, by the activities
of living organisms rather than physicochemically imposed upon them for their
response. Moreover, the state was regulated within the limits between which our
particular biochemical system could persist. There is still controversy about the
underlying mechanism of the regulation, but not about its existence. Such a
change in paradigm is key to our understanding of the mutual interactions of
climate and living organisms that this topic is about. By altering our atmosphere,
we challenge the entire biosphere system, and although we can predict some
immediate physical effects, we have little idea about what the ultimate biological
consequences might be.
The IPCC has made a range of predictions about how climate will change
over the regions of the Earth, based on a range of assumptions about how human