Can agriculture be made friendlier to the environment?
The Economist / March 25, 2000
THERE are few more powerful reminders of the fragility of human endeavour
than a storm which sweeps away half a country. In October 1998, Hurricane
Mitch roared through Honduras, Nicaragua and Guatemala, taking with it
10,000 lives and $5.5 billion-worth of the region's economy. Agriculture
was hard hit, but not all farmers suffered in equal measure. "Conventional"
farms using the industrial model of chemical-intensive monoculture had
60-80% more soil erosion, crop damage and water loss than those that had
practised "traditional" methods such as crop mixing, biological pest
control, water conservation and agroforestry.
Proof positive that agriculture defies nature at its peril? Not quite.
Agriculture is inherently unnatural, tethering the land to a single
purpose, but some forms are more unnatural than others. Since the second
world war, agriculture in the developed world has become increasingly
intensive, relying heavily on machines, chemicals, irrigation and
selectively bred plants and animals to coax more output from each unit of
land. This system has spread widely across the third of the world's land
given over to agriculture. It is the dominant model in North America,
Europe and Australia, and sits uncomfortably alongside traditional farming
practices in sub-Saharan Africa, Asia and Latin America. The model has been
remarkably successful in what it set out to do: to produce more abundant,
less expensive food. But such productivity has come at a price, much of it
paid for in four kinds of environmental damage:
Soil degradation. Almost two-thirds of all the world's agricultural land is
degraded to some degree, according to Stanley Wood at the International
Food Policy Research Institute in Washington, DC. Its sorry state is due to
compaction from running machinery over it; water and wind erosion; and
depletion of minerals and organic matter through overplanting and
overgrazing.
Salt, too, is building up through over-irrigation and poor soil drainage.
Roughly 20% of the world's irrigated land suffers from salinisation, which
makes it less productive. The most dramatic evidence of the perils of
excessive irrigation is the Aral Sea, where the water level has fallen by
two-thirds over the past 40 years, causing large-scale environmental
destruction and human misery. The recipient of its watery wealth -- an
8m-hectare expanse of irrigated cotton in Central Asia -- is losing
fertility because of growing salinisation.
Pollution. Although the use of synthetic fertiliser has declined in the
developed world over the past decade, the world still spreads 135m tonnes a
year, most of it in developing countries. The problem is not just how much
is used, but how it is applied. Much of it runs off to contaminate
aquifers, rivers and lakes.
The use of pesticide is running at roughly 2.5m tonnes a year, more than
double the figure 30 years ago. The use of a group of pesticides including
aldrin and DDT, known as the "dirty dozen", is restricted in many
countries, but they are still liberally applied in parts of the developing
world. Such persistent organic pollutants both linger and concentrate
throughout food chains, causing reproductive, developmental and
immune-system problems in both man and beast. And resistance to chemical
pesticides is growing among the organisms they are designed to kill.
Nor is it just synthetic chemicals that are a problem. Manure from
intensive livestock rearing which makes its way into soil and water is just
as damaging. Just look at the algal blooms now choking America's Chesapeake
Bay, largely thanks to nitrogen and phosphorus leaking into groundwater
from farms in Delaware, Maryland and Virginia. Even organic agriculture is
less innocent than it looks. Although it does without synthetic pesticides
and fertilisers, some of its "natural" alternatives, such as copper
sulphate, can be equally harmful.
Water scarcity. Roughly 40% of the world's food comes from the 5% of the
agricultural land that is irrigated. But the water is running out.
According to Sandra Postel, director of the Global Water Project based in
Amherst, Massachusetts, water is being pumped out of the ground faster than
it can be replenished, mainly because of the farmland thirst of America,
North Africa and the Arabian Peninsula, as well as China and India. Much of
this water is wasted through inefficient use, and agriculture is finding it
increasingly difficult to compete with new urban and industrial demands.
Biodiversity loss. The rich mix of creatures that make up ecosystems is
often irrevocably shaken up by intensive agriculture. According to the Food
and Agriculture Organisation, at least 13m hectares of forest -- providing
control of watersheds and a repository of potentially useful industrial and
medicinal compounds in plants, animals and micro-organisms -- is lost to
agriculture every year in developing countries.
Intensive monoculture also reduces genetic diversity. Some 7,000 crop
species are available for cultivation, but 90% of the world's food comes
from only 30 of them. Breeding programmes for much of the past half-century
have concentrated on high-yielding, pest-resistant, fast-growing crop
varieties, which now dominate over half of all the land planted to rice,
maize and wheat. The story is much the same in animal breeding, where over
a sixth of the 3,800 breeds of domestic animal that existed a century ago
have disappeared. This narrows the room for manoeuvre if disease strikes
and different strains are needed.
A quick fix
The tension between agriculture and ecology shows up clearly in the current
debate over transgenic crops. In 1999, about 40m hectares of genetically
engineered crops were grown by a dozen countries, a 44% increase on the
previous year (see 7). Most of the crops were bred to resist herbicides,
such as Monsanto's Roundup, or to produce insecticidal proteins, known as
Bacillus thuringiensis, or Bt, toxins. Such genes are now found in a
variety of commercial crops, such as soyabeans, maize, canola (oil seed
rape) and cotton, increasingly put together in one plant. Their corporate
purveyors promised higher yields with better pest control and lower
expenditure on chemicals.
The technology has yet to deliver on all its promises, but has provided
enough benefit to keep farmers planting. Four years after their launch,
these crops have been taken up by farmers far more rapidly than the
previous wonder, hybrid corn. Whether the inbuilt chemical protection of
such genetically modified crops has reduced the use of pesticide is highly
contested. A new study by Leonard Gianessi and Janet Carpenter at the
National Centre for Food and Agricultural Policy in Washington, DC, seems
to bear out both the hopes of farmers and the fears of environmentalists.
It finds that in 13 American states that have been growing transgenic
soyabeans, herbicide applications per acre have fallen by 9%, but 14% more
herbicide is being used in total because acreages have expanded as well.
And genetic modification has not increased yields.
"Post-emergence" herbicides such as Roundup, also known as glyphosate, work
by killing all the plants in the field, both weeds and crop: the point of
the genetic modification is to make the crop plants resistant to the
chemical. This should eliminate the need for tillage, thus reducing
mechanical damage to the soil. Gordon Wassenaar, who has been growing
soyabeans in Iowa since the 1950s and remembers the bad old days of the
highly toxic pestkiller DDT, is puzzled by the objections to GM crops. Like
other farmers, he finds glyphosate much safer. "It beats me how to please
these environmentalists. As soon as we meet one bar, another goes up."
Ecologists such as Margaret Mellon at the Union of Concerned Scientists
worry that genetic modification not only perpetuates the problems of
intensive agriculture but also adds new ones. They fret about the dominance
of one "broad-spectrum" herbicide that both reduces the biodiversity in a
field by killing all the plants and causes a few hardy weeds to develop
resistance. They also fear, not unreasonably, that the added gene might be
transferred from the crop plant to relatives in the field.
American maize farmers like Bt plants, crediting them with keeping levels
of their chief pest, the European corn borer, so low as to benefit both GM
and unmodified varieties. But such transgenic crops are even more troubling
to environmentalists who fear they will also make pests more resistant.
Last year, the news that pollen containing one of the Bt genes can stunt or
kill Monarch caterpillars enraged butterfly enthusiasts around the world.
The equally lethal effects on green lacewings got much less publicity, yet
these insects do a useful job by feeding on the corn borer. Researchers
have also shown that Bt toxins of the sort produced by the transgenic
plants stay in the ground longer than expected, and may kill local insects
and soil organisms. But these experiments were carried out in the
laboratory. Real-life results are less alarming, but more tests are needed.
Some of agriculture's most serious environmental problems -- such as lack
of water -- can be eased with technical solutions. Parched countries like
Israel have mastered a number of neat tricks -- such as using a continuous
drip of salt or waste water -- to make crops grow better. But how to
encourage others to adopt such practices?
Most countries have relied on a mixture of regulation and prohibition to
deal with environmental offences, such as taxing pesticides, penalising the
discharge of manure and removing fertiliser subsidies. Both the European
Union and America make direct payments to promote the use of less intrusive
forms of cultivation and the setting aside of land. This is designed to cut
production but has welcome environmental side-effects. On the whole,
however, carrots for good ecological behaviour are less common than sticks
for bad.
An exception is water marketing. Irrigation water is rarely priced at its
real value, but without a price tag it is often wasted. In Chile, Mexico
and California, however, farmers are able to trade "water rights" --
allocated by the state -- to those in need, such as industry. This seems to
encourage farmers to invest in water-saving technologies so they can sell
some of their rights, rather than quit altogether.
Having it all
Many ecologists, not content with improvements in conventional farming,
would like to see completely new ways of farming adopted. Or, rather, old
ways, going back to the traditions of half a century ago, when yields in
the industrialised West depended more on nature and labour, and less on
artificial aids. A mix of crops, trees and ground cover, rather than
monocultures, helped buffer pest infestations and severe weather. Nutrients
were recycled from livestock to crops. Nitrogen was introduced into the
soil by rotating the main field crops with pulses. Rotation also helped
keep down insects, weeds and diseases by breaking their life cycles. This
kind of farming caused less environmental degradation than today's
intensive, highly specialised agriculture, which produces much higher
yields but may prove hard to sustain in the long term.
Those who advocate going back to agriculture's roots argue that their
approach -- known as agro-ecology -- is just as scientific as the latest GM
technology, because it relies on a detailed understanding of the complex
interactions between soil, water, plants and animals. Miguel Altieri, an
agro-ecologist at the University of California at Berkeley, points out that
this is not the same as much of modern organic agriculture, which still
largely relies on monoculture.
But in a world of industrialised farming, agro-ecology is hard to put into
practice, if only because of the vested interests of agribusiness. One
company that is easing itself towards encouraging this kind of agriculture
is Unilever. For the past two years the Anglo-Dutch giant has been running
pilot projects with growers to spread expertise around the world. It has
found, for example, that natural forest left among its Kenyan tea
plantations harbours insects that keep nasty bugs in check and acts as a
windbreak, as well as providing fuel for the locals. This technique is now
being passed on to the firm's plantations in India. Producers venturing
into agro-ecology hope that it will lower their costs in the long run. But
conversion is expensive, and although consumers say they want "clean, green
and pristine" agriculture, they are not always willing to pay a higher
price for it.
(posted without permission)
