Saturday, November 15, 2008

Sugar and the Environment

High Fructose Corn Syrup has a bad reputation for many reasons; both its health and environmental effects have been derided quite a bit in the last few years. As I examined in this post, some of these have more merit than others. Before one decides to switch from HFCS to sugar for environmental reasons, however, the ecological effects of sugar cane should be examined. My inspiration for this post was a segment of Bill Nye's "Stuff Happens" on Planet Green. He pointed out that sugar production is killing the Great Barrier reef and the Everglades, so I thought I'd dig around a bit to see what others had to say.

Digression: Am I the only one who finds a lot of Planet Green's programming to be really annoying? I can only take so much of Hollywood-types telling me how much money they "save" by installing PV solar cells on their roofs of their 10,000 sq.ft. palatial estates. Sure you have a smaller power bill...but how much did you spend upfront to install them? Have your accountant run the real numbers and get back to me. Don't go patting yourself on the back to hard, you might strain something. Anyway, back on track...

According to this report, Sugar and the Environment, produced by the World Wildlife Fund, cane sugar has some major effects on the environment. The report is very detailed, but I will include some highlights here.

The cultivation and processing of sugar produce environmental impacts through the
loss of natural habitats, intensive use of water, heavy use of agro-chemicals, discharge and runoff of polluted effluent and air pollution. This leads to the degradation of wildlife, soil, air and water where sugar is produced and of downstream ecosystems.

Although many of the environmental impacts of cane and beet cultivation are generic to agriculture, some impacts are distinct, particularly in their severity. Impacts relating to irrigation of sugar cane and pollution runoff are of particular concern.
Environmental Impacts
Sugar cultivation and processing impacts on biodiversity and ecosystem services at the field, farm and wider landscape levels.
Field Level: Soil erosion, compaction, salinisation and acidification

Farm Level:
The suite of micro-organisms associated with a crop is often overlooked, although it
plays such a critical role in ecosystem function, for example in the turnover of soil
organic matter. Most intensively cultivated agro-ecosystems are relatively lacking in
Landscape Level:
Impacts of sugar cultivation on downstream ecosystems: Agriculture is arguably the
predominant influence on the Earth’s land surface and undoubtedly represents the
main cause of wetland habitat loss. This occurs through the runoff of polluted effluent
into water courses, due to the heavy abstraction of freshwater resources upstream
of wetlands habitats, or by altering the natural flow regime.

The impacts felt downstream are the cumulative result of a complex set of land
and water use decisions in a river basin. Within this context, cane or beet can play
an important role in some sugar producing countries.

The sugar industry in Australia has been a significant player in major infrastructural projects, including damming of the Burdekin, Tully and Barron Rivers, which has altered the pattern of freshwater flow into the Great Barrier Reef lagoon.
Cane growing has shown to increase sediment and nutrient loads, particularly following heavy rainfall, which can carry these materials into the sea, reducing water quality and impacting on inshore reefs. The sediment export rate in the lower South Johnstone River has been estimated at 180,000 tonnes of fine sediment/year, with sugar cane farming contributing to these sediment loads.

Phosphorus-rich runoff from sugar cane fields in Florida is held largely responsible for the decline of the Everglades. The Everglades is a naturally nutrient-poor wetland where sawgrass thrived because naturally low levels of phosphorous inhibited the growth of more aggressive species, such as cattails. However, the common practice of spreading phosphorus on the cane fields in the Everglades first caused the sawgrass to grow abnormally large before dying back to give way to cattails, which have now spread across more than 50,000ha of conservation areas, crowding out willow and bay and excluding fish.
Causes of Impacts

Habitat Clearance
Half of the world’s wetlands have been lost to drainage and conversion to agriculture
(70-90 percent in Europe and USA), and even protected wetland areas are subject
to agricultural impacts. Low-lying and alluvial areas in particular have typically been
reclaimed and drained for sugar cane cultivation, as they often support the richest
soils and enjoy a good natural water supply.
Overuse of Water
Although sugar cane is an efficient converter of biomass from water, it still needs about 1500-2000mm/ha/year and ranks among a group of crops noted for their significant water consumption (along with rice and cotton). It is a deep-rooted crop, which remains in the soil all year round and is able to extract soil water to depths well below one metre. In areas where sugar cane growth relies on rainfall, the crop can influence river flows as it intercepts run-off from the catchment into rivers and taps into ground water resources.
Intensive Use of Chemicals
Intensive agricultural food production in general uses high levels of pesticides
(herbicides, insecticides, fungicides, nematicides, rodenticides, plant regulators,
defoliants or desiccants), with herbicides representing about 50 percent of pesticides
used in many countries. A wide variety of pesticides are used in the cultivation of sugar crops. Herbicide use in sugar beet is among the highest compared to other crops.
Discharge of Processing Mill Effluents
Perhaps the most significant impact from cane and beet processing is related to
polluted effluent. In some countries with weak environmental laws, when sugar mills
are annually cleaned, a tremendous amount of matter is released, which is usually
discharged straight into streams. Cane mill effluents tend to be relatively rich in organic matter compared to other sources, and the decomposition of this matter reduces the oxygen levels in the water, affecting natural biochemical processes and the species inhabiting those freshwater systems. Potential pollutants in these effluents include heavy metals, oil, grease and cleaning agents.
Pre-Harvest Cane Burning
In many sugar producing countries, the cane fields are burnt immediately before harvesting
for easier cutting, post harvest cultivation and pest control.
While it has benefits, it also causes air pollution, soil degradation and a reduction in sugar yield.

Another thing to keep in mind is the distance sugar takes to get to your plate. Since it is primarly grown in tropical climates, it may have been shipped thousands of miles. This would no doubt increase the "carbon footprint". Luckily, we produce a lot domestically in Florida, but this is not without environmental consequences.

As this report (and Bill Nye) points out, even the most unassuming and ubiquitous products can have large, and perhaps unrealized, environmental impacts.

Other Sugar posts:
Evaporated Cane Juice: Part I
Evaporated Cane Juice: Part II
High Fructose Corn Syrup
Caramel Apples
Alternative Sugar Names
A Look at Agave

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