Environmental Engineering Reference
In-Depth Information
cohesion and a deficiency in 'social capital' - that is, a loss of institutions and
community structures that help society and its component communities to
work harmoniously and productively? If so, why is that not also affecting
population health and well-being?
There are three possible explanations for this apparent paradox:
i
modern human societies, via technological, economic and political
achievements, have acquired near-immunity to adverse external
environmental circumstances;
ii
adverse health effects
are
already occurring, but we have not yet
detected them. Not only is the real world of disease causation multi-
causal and 'noisy', but we have no null comparison data (that is no
global population living in an unstressed environment);
iii
there is a lag period between the decline in environmental conditions
and the occurrence of health impacts. This lag reflects both
complexity of process and the protective buffering afforded by
human culture.
The first explanation is not tenable - and, anyway, it is countered by long
human experience. Throughout history, even as technologies have
advanced, great civilisations, as in Mesopotamia, Egypt (the Old Kingdom),
the Indus Valley, Mesoamerica, Peru and elsewhere, have crumbled in the
wake of environmental infrastructural decline (McMichael 2001b). Today,
various countries, including China and Australia, are experiencing the
adverse environmental consequences of land clearing, over-exploitation of
arable land and excessive reliance on irrigation. Underlying all such accounts
is the fact that human societies are necessarily beholden to ecological limits
and the laws of thermodynamics, and therefore cannot live apart from the
natural world. That is, the human economy is a wholly dependent subset of
the natural 'economy'. Therefore, in the longer term, if not sooner, there can
be no immunity of modern human societies to the consequences of environ-
mental degradation and the weakening of ecosystems. Most probably, then,
the best explanation for the apparent paradox is a combination of the second
and third items above.
Future prospects for population health
Over the next few decades, life expectancies will probably continue their his-
torically unprecedented rise, especially in low-income countries as they
