Environmental costs
Climate change
Environmental degradation is probably the most widely discussed cost of industrial agriculture today. This is partially due to climate change and the attention this receives from a broad segment of the population. The potential damage that will occur from the phenomenon (e.g. global warming, increased hurricane incidence, and higher sea levels) has prompted scientists and policy makers to find its causes and ways to reduce their future impact. Of course, agriculture has been identified as a major cause1.
Agriculture is a major producer of greenhouse gases, including carbon dioxide, methane, and nitrous oxide. For example, carbon dioxide is a by-product of oil consumption. In industrial agriculture, it takes gas to grow the corn that feeds a cow and then ship its meat to the local grocery store. All in all, it takes about a gallon of gas for each pound of beef produced2. But, it’s not only the inputs that cause air pollution. Cattle in the U.S. ‘output’ 184 billion cubic feet of methane every year – enough to fill 4 million blimps. This output accounts for 16% of the produced methane3.
The land use changes associated with agriculture also contribute to carbon dioxide release (e.g. forests that are cut down can no longer act as carbon sinks). In addition, land use changes, by altering how the energy is absorbed and reflected, also impact the amount of radiation energy that is entering the atmosphere.1
Deforestation
Deforestation is another major problem. Logging plays a role but most forests are cut down to make room for more ranches and plantations. Slash-and-burn techniques are probably the major contributor to deforestation (of course, slash-and-burn is not industrial agriculture but it has the similarity of intensively farming the ground – industrial agriculture only postpones nutrient depletion by adding large amounts of fertilizers)4.
Deforestation reduces the content of water in the soil, groundwater, and atmospheric moisture. It contributes to the run-off of rainfall, which intensifies soil erosion. It is also a factor in desertification5. Primary forests are some of the richest in terms of biodiversity and forest disturbance and deforestation lead to major losses in the numbers and kinds of plant and animals species6.
Just when counting the Earth’s rainforests, the costs of deforestation amount to $5 trillion a year. As an example, this figure accounts for the losses to plant, animal, and genetic biodiversity that is subject to extinction. Also, revenues of the pharmaceutical trade are drastically cut, as up to half of its $640 billion market comes from genetic resources7.
Forest after slash-and-burn
Water pollution
Water pollution will be addressed by looking at the Chesapeake Bay and its problems with pollution. The problems seen in the Bay are a good example of the water problems seen around the globe.
Starting in the 1970s, scientists began to notice a disturbing shift in the Bay’s ecology8. The Bay had largely been a system that was driven by life in the benthos – namely the submerged sea grasses, which help produce the oxygen necessary for organisms such as crabs and fish. However, the grasses soon began to die and the oxygen that they produced was quickly depleted. This left a massive anoxic region in the Chesapeake – in 2006, the region was about a cubic kilometer9. The lack of oxygen has left a ‘dead zone’ in the middle of the Bay, which makes it difficult to support life in the benthos and damages the trophic levels that depend on these organisms for nutrition.
An example of this damage is the iconic blue crab. First, the die-off of the sea grasses has caused a loss of habitat – the crabs use the grasses as hiding spots as juveniles and post-molting and as foraging sites. Next, the death of bottom-dwelling organisms robs the crabs of a vital food source, hurting their numbers, which are already weakened by overharvesting. Also, pockets of oxygen-poor water often lead crabs to escape onshore in masses in a phenomenon called a ‘crab jubilee’10.
Crab jubilee – crabs escaping anoxic water Eelgrass – an important Chesapeake sea grass
So, what exactly did kill the grasses, leading to the anoxic conditions? Scientists at first believed it was the result of industrial and agricultural chemicals. There was good reason for this suspicion as the Bay and its tributaries were known to receive large amounts of these pollutants. For example, the pesticide Kepone was being flushed into the James River from its production plant in Hopewell, Virginia during the 1970s. Many victims of Kepone poisoning were identified and the River was entirely closed off to fishing after fish were discovered to be carrying toxic levels, costing millions of dollars to the fishing industry in the region11. However, as damaging as these chemicals were, they were not the cause for the sea grass die-off.
Eventually, scientists identified the nutrients phosphorus and nitrogen as the culprits. These nutrients fuel large blooms of algae that shadow the grasses on the bottom. Without light, the grasses are unable to perform photosynthesis and eventually wither and die.
Nitrogen and phosphorus are produced by sewage-treatment plants, air pollution, and power plants. However, agriculture is the primary culprit, which contributes 40% of the nitrogen and 50% of the phosphorus runoff12. Each year, about 300 million pounds of nitrogen and 15 million pounds of phosphorus enter the Bay13. These numbers are much higher than the set Total Maximum Daily Loads (limits on how much nutrients can enter the Bay without impairing its health), which stand at 187.4 million pounds for nitrogen and 12.5 million pounds for phosphorus14.
Calculating environmental costs
This section will conclude with a link to a site that provides a good general introduction to how the value of ecosystems and the environment are calculated: http://www.ecosystemvaluation.org/.
This site looks at a number of valuation calculating methods including ‘market pricing’ and ‘productivity pricing.’ For those interested in how these values are calculated, this site is well worth looking at.