04 Why does conventional farming damage the environment?
Soil and water pollution
Rain and irrigation can lead to agrochemical run-off, which contaminates waterways
and causes adverse impacts on aquatic ecosystems as a result of toxic effects.9
This includes blue-green algae blooms that are so dangerous they can sometimes be
fatal to livestock, wildlife, marine animals and even humans.10 A build-up
of chemicals in the soil can impact plants, which in turn can be transferred to
wildlife and humans who eat the plants.
A local example of this is the Great Barrier Reef, where studies have found that
runoff from fertilisers used at nearby farms is adding nitrogen and phosphorous
into the oceanic ecosystem, causing massive algae growth that leads to depletion
in oxygen available for other creatures and decreases the biodiversity in those
Soil and land degradation
Soil and land degradation is caused by human mismanagement of soils, mostly due
to agricultural activities including the use of agrochemicals used in farming.
A report on the global assessment of soil degradation states that 'the earth's soils
are being washed away, rendered sterile or contaminated with toxic chemicals at
a rate that cannot be sustained' 12 Today almost a quarter of the world's
farmland is affected by serious degradation, up from 15% two decades ago.
The Food and Agriculture Organisation (FAO) study indicates the world may currently
be losing about 1% (50,000 sq kms) of its farmland annually ' due to a combination
of degradation, urban sprawl, mining, recreation, toxic pollution and rising sea
levels (see The Coming Famine).
Chemical fertilisers and pesticides are derivatives of fossil fuels, including oil
and natural gas. The use of fossil fuels is the reason the earth is experiencing
dangerous climate change. In Australia, agriculture is the second biggest contributor
to global warming by sector, contributing 15% of Australia's greenhouse gas emissions.13
The use of oil is essential to modern agricultural practices. Oil is used in the
pumping of water for irrigation, the machinery used on the farm and the long road
of transport from the farm all the way along the supply chain to our plate. Oil
is so interlinked with our food system that the price of food is closely correlated
to the price of oil. Oil prices are a key contributing factor to the increase in
the price of food. We saw a spike in food prices in the 1970's, which correlated
with the oil crisis at that time and again during the food riots of 2008.14
Farmers in developing countries are the hardest hit by rises in oil and subsequent
fertiliser costs because they have just begun the switch to Western, oil intensive
systems of food production. This is illustrated by the fact that China has increased
its fertiliser usage by 44% in recent years, India 33%, Pakistan 61% and Brazil
137%. In contrast, Europe has cut its fertiliser use by half15 as farmers
return to organic and agro-ecological farming methods.
Loss of biodiversity
Conventional agriculture favours growing large mono-crops of single food varieties,
dramatically reducing the biodiversity of the food we eat. For example:
- There is an estimated 23,000 edible plants of which we only eat around 400.16
- Between 1804 and 1904 there were 7,098 apple varieties documented as having been
in use in the USA. Today, approximately 86% of these varieties have been lost.17
- In Brazil only 12 out of the 32 native pig breeds are left and all are under threat.18
Humans are increasingly vulnerable due to the loss of food biodiversity. If a pest
or disease invades a monocrop then the risk is that the entire crop will be lost.
The greater the diversity of food varieties we eat, the more protected we are to
'shocks' in the system.