Faced with a future
replete with erratic weather, shifting rainfall
patterns and loss of genetic diversity from the
effects of global warming, there are choices that
we as citizens can make which can help to reverse
the suffocating effects of globalization and the
associated consumption of fossil fuels. In addition
to driving less carpooling and using mass transit,
growing food at home and increasing regional food
production can reduce corporate control of our
food supply and alleviate global ecological crises.
(Karl, 3-12)
Overall it is estimated that the US food system
consumes 17% of our country's huge total of fossil
fuels. Only 3% of that total is directly attributed
to on-farm food production. The remaining fuels
are consumed in packaging, processing and transportation
of agriculture's produce. The vast distance between
consumption and production of food is one aspect
of our out of whack industrial food system. The
average morsel of food consumed in the US travels
an average of 1300 miles before it is eaten.
In 1880 fully one half of the US population was
employed in agriculture. In today's industrialized
US food system less than 2% of our population
are farmers, while in contrast in India. 75% of
their population is engaged in agriculture. The
US leads the world in CO2 emissions with 19.5
tons a year contributing to the problem of global
warming. Each of India's billion people only contribute
.81 tons of CO2, making our individual contribution
24 times greater. (Santer, 39-46)
In the past 25 years US agriculture has become
22% less efficient as more and more tasks are
becoming mechanized. Increases in the price of
fossil fuels will ultimately result in increasing
food costs, reflected in the level of petroleum-based
transport energy imbedded in the food. Community
food security is hinged upon this important fact.
Increasingly our planet's population is becoming
urbanized, with an increasing proportion of those
people living in poverty. Current estimates show
that as many of 800 million people in the world
are malnourished, with fifty-seven percent of
them urbanized. Is there a way to feed the hungry
urbanites?
As little as 100 years ago Paris was an agriculturally
productive city, where approximately one sixth
of the land was dedicated to food production.
On that space Parisians annually produced l00,000
tons of high-value vegetable crops. This production
was matte possible through the availability of
manure from the city's vast population of horses,
which provided the power for the public works,
fire department, and transportation of the city's
populace. The key to any sustainable agriculture
is the increased use of non-fossil fuel energy
sources like draft animals. While 19th century
Paris stables contributed a million tons of manure
annually to grow food and sustain the population,
modern city's automobiles clog urban areas and
give us atmospheric and water pollution, as they
secularize our world.
In some cities agriculture continues to play a
significant role in providing residents with their
sustenance. In Hong Kong today 45% of the vegetables
consumed in the city of 6.7 million people are
grown on 5-6% of the total land area . Singapore,
a Republic of 3.5 million and a population density
of 14 000 per square mile produces 80% of its
poultry needs and 25% of it vegetables. Growing
food 1ocally insures higher quality, fresher and
more nutritious foods, reduces energy consumption
and assures greater access to food for more people
especially the poor. (McMichael & Haines,
805-9)
America's animal powered agriculture wasn't really
so long ago. As late as 1955 the number of horses
and mules on US farms equaled the number of tractors.
Prior to the industrial revolution it required
716,000 kcal of energy to produce one hectare
of corn, whereas today's consumption is 11 million
kcal or an increase of 1500 percent. Meanwhile
harvests have only increased 350 percent. Adding
to the unsustainable practices of agriculture
is the massive increase of fertilizers which,
in the years 1945 to 1983 increased by a whopping
2000%. In the same period the number of insect
pests that became resistant to insecticides leaped
from 7 to 447. Today in California alone the annual
application of pesticides is an astounding 100,000,000
pounds.
While there are plenty of examples to show agriculture's
ravenous depletion of natural resources, there
are likewise ample ways to demonstrate possible
alternatives. Agriculture has been successfully
practiced around the world by primitive cultures
for thousands of years before the "green
revolution" which, contrary to glowing reports
made by the corporate interests who have profited,
has had severely damaging environmental and economic
consequences Worldwide. Native people on this
continent were engaged in agriculture 7000 years
before the first European settlers arrived in
Jamestown Virginia. Indigenous agriculture was
polycultural, in contrast with today's monocultures,
and provided protection from pests and diseases
in addition to contributing to diversified economies.
(Working Group…, 1341-9)
Obviously our world is vastly different than
that of pre-Columbian America, but it is more
vital today than ever that our actions remain
in harmony with nature to protect the ecology
of the Earth. It may seem preposterous to suggest
that farmers in Iowa and California put their
tractors in mothballs and instead use hoes and
dibble sticks, put its not so far fetched to consider
the potential for wide-spread climate change combined
with species extinctions, loss of ecological process
and depleted aquifers to evoke widespread famine
and crop failures across the globe if industrial
agriculture continues in its present form. For
example, the projected rise of sea levels due
to climate changes will eliminate 30% of the world's
cropland.
Extreme events such as 100-year floods are happening
every decade; the drought continues in some regions
like the Great Lakes where the snow pack is at
an all time record low and the American south
is likewise in the midst of a drought not seen
since the famous dustbowl years of the 1930's.
When will our country wake up and smell the CO2
fuming from the tailpipes of our cars and trucks
and realize that our lifestyles are choking the
life out of the earth? (Working Group…,
1341-9)
Over the past few decades many countries have
experienced an increase in both morbidity and
mortality from asthma. Air pollution is a possible
culprit, and researchers have paid special attention
to NO2 concentrations, which have risen steadily
as the result of burning of fossil fuels, mainly
from motor vehicle engines. Epidemiological and
clinical studies have addressed the effects of
exposure to low concentrations of NO2 on respiratory
health indoors and outdoors. Most of the studies
assessing the relation between indoor NO2 and
respiratory health have been conducted in children
and the results are inconsistent. (Samet et al,
1258-65) In adults, many experimental studies
have been conducted, showing on average a small
increase in airways reactivity to NO2 by comparison
with clean air. (Folinsbee, 273-83) However, the
approach of exposing subjects to individual pollutants
bears little resemblance to the complexities of
atmospheric pollution. Molfino et al (199-203)
used a different approach--low concentrations
of ozone--to test and corroborate the hypothesis
that air pollution enhances airways responsiveness
to ragweed and grass allergens. Two recent reports
in The Lancet show that NO[ sub 2] alone (Tunnicliffe
et al, 1733-36) and in combination with SO2, (Dayalia
et al, 1668-71) at concentrations that may be
encountered in daily life, enhance the bronchoconstrictive
response to inhaled house dust mite in patients
with mild asthma. Neither of these latest experimental
studies allows estimation of the clinical magnitude
of the reported functional change, although Tunnicliffe
et al (1733-36) suggest that these effects are
likely to be small.
Increased airways reactivity is not the only
effect induced by low levels of NO2. Devalia et
al, (1308-16) in an in-vitro study, found that
exposure to 400-800 ppb of NO2 caused bronchial
epithelial cell dysfunction. Whether the enhanced
airway reactivity to inhaled allergens is the
consequence of cellular damage remains unclear.
Aris et al (1363-72) showed that exposure of healthy
subjects to 200 ppb of ozone was followed by an
influx of inflammatory cells into the airway,
although there was no correlation with spirometric
changes. Concurrent exposure to different air
pollutants could induce significant inflammation
and enhance the reactivity of asthmatics to a
wide range of asthma triggers. Derails et al (1668-71)
showed that joint exposure to NO2 and SO2 led
to increased bronchial reactivity to allergens
whereas NO2 alone did not. The more complex mixtures
of pollutants likely to be present in urban air
could induce even larger inflammatory and functional
changes than the ones reported so far. Thus, the
effect of air pollution on allergic asthma could
be larger than that seen in the experimental studies.
From a public health perspective, we need to
know the size of the population at risk; and to
determine that we need to integrate the individual
opportunities for exposure at specific time-space
ordinates. Here both indoor and outdoor sources
of NO2 are relevant. In a US study, cooking with
a gas stove generated concentrations of 200 to
400 ppb of NO2, with transient peaks as high as
1000 ppb. (Harlos, 1211-23) In a study of children
in New Mexico, Samet et al. (Samet et al, 1258-65)
found that, in 30% of their bimonthly calls, children
reported having been in the kitchen while meals
were being cooked during the previous 24 hours,
for an average of 20 minutes. However, frequency
and characteristics of these indoor exposures
to NO2 probably differ from one country to another.
Outdoor levels of NO2 around 400 ppb are reached
only during the severe air pollution episodes
that occur sporadically. Peak hourly levels of
382-423 ppb were recorded during a pollution episode
in London in December, 1991. (Brought GFJ, 598-623)
Thus, while it is clear that allergic asthmatics
can experience cellular and functional damage
if exposed to levels of NO2 of 400 ppb or higher,
we do not know either the magnitude of the subsequent
clinical effects or the prevalence of exposure
of asthmatics to such levels of pollution. This
lack of knowledge hinders a more precise evaluation
of the problem from a public health perspective.
Increasing levels of NO2 over recent decades
could have influenced asthma in two ways: (a)
by decreasing the threshold of allergen exposure
needed to develop sensitization and allergic asthma;
and (b) by increasing morbidity of existing asthma.
There is growing evidence for the latter possibility.
(Tunnicliffe et al, 1733-36; Devalia et al, 1308-16)
By contrast, evidence for an increased incidence
of asthma due to air pollution has not yet been
provided. However, if NO2 and other air pollutants
increase the permeability of bronchial mucosa
to allergens, (Devalia et al, 1308-16) the threshold
for allergen exposure to produce sensitization
may decrease and the incidence of allergic asthma
may increase.
Until lately the association between NO2 and
asthma was inconsistent. The studies reported
by Tunnicliffe et al (1733-36) and by Devalia
et al (1668-71) confirm the findings reported
by Molfino et al (199-203) for ozone and should
stimulate further research to characterize the
synergism between NO2 and aeroallergens as causal
or contributory factors in asthma.
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