Environmental Engineering Reference
In-Depth Information
The environmental impacts of jute production are modest. Bangladeshi farmers use
only modest amounts of chemical fertilizers and little pesticide on the crop. The country's
fl
sh populations, an important positive externality for
rural people. Like all plants, jute sequesters atmospheric carbon, a further positive exter-
nality. At the end of the product life cycle, jute biodegrades in the soil.
Polypropylene, jute's main competitor, is manufactured by multinational petrochemi-
cal
ooded jute
fi
elds support diverse
fi
rms. The USA is the world's leading producer. Polypropylene production generates
emissions of numerous air pollutants, including particulates, sulfur oxides, nitrogen
oxides, carbon monoxide, volatile organic compounds, and other toxins, in addition to
carbon dioxide. Since it is not biodegradable, polypropylene generates further environ-
mental costs in the form of land
fi
fi
ll disposal, incineration, or litter at the end of the
product life cycle.
The price advantage that has helped polypropylene to displace jute arises in no small
measure from the failure of market prices to internalize environmental costs.
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The result
of the global competition between the two has been the displacement of a relatively
'green'
southern product by a relatively 'brown'
northern product.
Even within
Bangladesh, plastic shopping bags have begun to replace jute ones.
Maize: Mexico versus the USA
Maize is the leading crop in both Mexico and the USA.
Competition between producers in the two countries has intensi
ed in recent years, as the
Mexican government has cut support to small farmers and lowered maize tari
fi
s.
Mexico is the historic center of origin of maize, and the modern center of the genetic
diversity in the crop. In the hilly lands of southern and central Mexico, campesino farmers
grow thousands of di
ff
erent varieties of maize in small plots that botanists call 'evolu-
tionary gardens' (Wilkes, 1992). On these farms, the maize plant continues to evolve with
the assistance of the human hand - in the process Darwin called 'arti
ff
cial selection' - in
response to climate change and newly emerging strains of pests and plant diseases. The
campesinos thus provide a valuable positive externality to humankind - the
in situ
con-
servation and evolution of genetic diversity in one of our main food crops.
In the USA, fewer than a dozen varieties account for half of total acreage under maize.
Only a few hundred varieties, many of them closely related, are commercially available.
The crop therefore su
fi
ers from genetic vulnerability - the eggs-in-one-basket syndrome -
a problem dramatically revealed in 1970 when a new strain of leaf blight destroyed one-
fi
ff
ort to remain a step ahead of evolving pests
and pathogens, US plant breeders run a 'varietal relay race', constantly developing new
varieties that incorporate resistance to new threats. The average commercial lifespan of a
US corn variety is only seven years. The raw material for this race is the genetic diversity
found in the evolutionary gardens of traditional agriculture.
By the measuring stick of market prices, US farmers are more 'e
fth of the nation's corn harvest. In the e
ff
cient' than their
Mexican counterparts. Before NAFTA, US maize sold at roughly $110/tonne at the
border, whereas Mexican growers received $240/tonne. Several factors contribute to the
price advantage of US corn: (i) natural conditions such as better soils, more regular rain-
fall, and a killing frost that limits pest populations; (ii) farm subsidies that reduce US
market prices; (iii) the externalization of environmental costs, such as groundwater
contamination by pesticides; and (iv) the failure of market prices to internalize the value
of sustaining genetic diversity provided by Mexican farmers.
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