Are the policy implications of the precautionary principle coherent?
As formulated in the 1992 Rio Declaration on Environment and
Development, the precautionary principle states that " . . . lack of
full scientific certainty shall not be used as a reason for
postponing cost-effective measures to prevent environmental
degradation." The precautionary approach has led many European
countries to ban genetically modified (GM) crops on the supposition
that developing GM crops might lead to environmental degradation.
The countries are correct that this is an implication of the
principle. But is it the only implication?
Suppose global warming intensifies and comes, as some now
darkly predict, to interfere dramatically with food production and
distribution. Massive dislocations in international trade and
corresponding political power follow global food shortages, affecting
all regions and nations. In desperate attempts to feed themselves,
billions begin to pillage game animals, clear-cut forests to plant
crops, cultivate previously non-productive lands, apply fertilizers
and pesticides at higher than recommended rates, kill and eat
endangered and previously non-endangered species.
Perhaps not a likely scenario, but not entirely implausible,
either. GM crops could help to prevent it, by providing hardier
versions of traditional lines capable of growing in drought
conditions, or in saline soils, or under unusual climactic stresses
in previously temperate zones, or in zones in which we have no prior
On the supposition that we might need the tools of genetic
engineering to avert future episodes of crushing human attacks on
what Aldo Leopold called "the land," the precautionary principle
requires that we develop GM crops. Yes, we lack full scientific
certainty that developing GM crops will prevent environmental
degradation. True, we do not know what the final financial price of
GM research and development will be. But if GM technology were to
help save the land, few would not deem that price cost-effective.
So, according to the precautionary principle, lack of full scientific
certainty that GM crops will prevent environmental degradation shall
not be used as a reason for postponing this potentially
The precautionary principle commits us to each of the following
(1) We must not develop GM crops.
(2) We must develop GM crops.
As (1) and (2) are plainly contradictory, defenders of the
policy should explain why its implications are not incoherent.