198 The Environmental Debate
has created a demand for otherwise worthless
catch because it can be used as feed. In some
countries, shrimp farmers are now investing in
trawl nets with fine mesh to catch everything
they can for shrimp food, a practice known as
biomass fishing. Much of the catch are juveniles
of valuable species, and so these fish never have
the opportunity to reproduce.
Fish farms can hurt wild populations
because the construction of pens along the coast
often requires cutting down mangroves—the
submerged roots of these salt-tolerant trees pro-
vide a natural nursery for shrimp and fish.Source: Carl Safina, “The World’s Imperiled Fish,”
Scientific American 273 (November(1995): 48-49.DOCUMENT 148: Edward Tenner on Shifting Liability (1996)
Surely the scientists who developed DDT did not anticipate that the pesticide would drive the bald eagle and
several other prized species to the brink of extinction. Neither did the builders of the electric power stations in
the Ohio Valley anticipate that acid rain would result from the construction of the tall smokestacks that rid the
region between Pittsburgh and Cincinnati of much of its pollution.
Edward Tenner, a historian who writes and lectures about the history of science and technology, questions
whether many so-called scientific, technological, and medical advances of the twentieth and twenty-first
centuries are not merely shifting the nature of environmental liability. While sixteenth-century scientists and
philosophers such as Francis Bacon [see Document 8] believed that technology would give humans control
over nature, in the late twentieth century it became increasingly evident to more and more people that it
is impossible to foresee all the consequences of a technological innovation^15 or to predict precisely how an
ecosystem will respond to its manipulation.Classic disasters were deterministic. Cause
and effect were linked. An exploding boiler
killed those it killed, and spared those it spared.
Late-twentieth-century disasters are expressed
as deviations from a baseline of “normal” back-
ground tragedy. The truth is not in immediate
view. It emerges from the statistical inferences of
trained professionals.
...
The old disasters were localized and sudden.
New ones may be global and gradual, from radi-
oactive isotopes in milk in the 1950s to climate
change in the 1990s.
Our control of the acute has indirectly pro-
moted chronic problems. Medical researchers have
recognized this trend for years and have been shift-
ing their efforts to chronic diseases—though so far
not with the same results they have had with injury,
infection, and acute illness. Our ability to transport
animals and plants among continents, deliberately
and accidentally, has on balance been decreasing
rather than promoting species diversity. But the
invaders have also failed to be as catastrophic to trees
and crops as some had feared. Like many chronic
illnesses, they have become manageable nuisances,
neither conquerable nor fatal, but demanding time-
consuming vigilance. Our efforts to modify our
environment have also produced chronic problems:
the comforts of home have helped produce the
annoyances of allergies, suppressing forest fires has
helped make them a greater threat, and protecting
the shoreline is helping to erode it.
* * *
By intensifying our protection against some
forms of natural danger, we have sometimes only
shifted greater liability to the future: a rearranging
effect. We have traded acute problems for gradual
but accumulating ones. This is especially true of
the environmental disasters affecting energy.Source: Edward Tenner, Why Things Bite Back: Technology
and the Revenge of Unintended Consequences (New York:
Knopf, 1996), pp. 24-25, 72.