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Fruit tree numbers near zero are not an aberration.
The 2008 fruit tree explosion was not merely a mild affliction of trees. It was a physical manifestation of a larger, long-term, and serious problem: our excessive and unacceptable demand for and the increasingly unaffordable cost of fruits, vegetables, and nuts and seeds. At least four times in the United States, two or more events have taken place within the past decade in which a combination of rising food prices, excess demand, and drought decimated fruit- and nut-producing areas of the country.
Today, with thousands of acres of cropland lying fallow in the United States, many fear that a "second wave" of agriculture failures might be imminent. The latest crop has been a disappointing one. But with the possibility of a climatic cycle change-and with fruit trees offering a buffer against the potential impacts of changing temperatures and rainfall-far less likely is a scenario in which the so-called Second Wave of Agriculture Failure is underway. There is still time, and we must take steps to preserve, restore, and build-up crops, fruit trees, and pastures.
Of the other staples, fish are the most vulnerable to climate change, with wild salmon populations in the Pacific Northwest already in steep decline. "Salmon depend on streams with slow-moving, stable flow," explains Dave Goulson, a geneticist at Britain's Imperial College, and author of Trawlers, Farms and Forests: Culturing the Scottish Environment and reducing the environmental impact of agriculture. As sea levels rise and currents change, the habitat that a salmon needs to grow and mature will shrink.
Unfortunately, it appears that conventional practices of fishing for farmed salmon, coupled with pollution from dyes, feeds, and fish slurry, are causing further damage to wild salmon. In fact, much of the increased production of farmed salmon may have come at the expense of the natural salmon population. In addition to putting wild salmon at risk, the farmed salmon is largely being eaten by humans, possibly putting pressure on wild stocks. "I think it is too late to save the wild stocks," says Goulson. "And I would not be very optimistic about the productivity of the remaining wild stocks. The farms are likely to eat up what is left."
In fact, it may be too late even for the domesticated species. As fish in large reservoirs experience lower water quality, disease, and food availability, fish farmed in ponds may be reduced to bugs and low-grade feed, and those on a diet of shrimp are showing a greater propensity to develop liver or heart damage. Some farmers have already come to that conclusion. In 2012, Oxford University scientists, who had previously studied wild salmon, discovered a critical parasite that typically infects wild salmon in Iceland. They then asked farmers to farm their fish on the side and found that farms contained far fewer parasites. "It was interesting," says Goulson. "The notion was that the parasite requires wild-salmon food, and that it is acquired from wild salmon in rivers." In other words, farmers were able to harvest wild salmon as part of the parasite's life cycle.
And while industrial-scale fish farming provides one lifeline for some salmon, it is hardly a win for everyone. Salmon farming, in general, is far more energy-intensive than organic farming, which itself is not a guaranteed, or even environmentally sensitive, food source. Further, as production booms, the cost of fish fertilizer and feed may push up the price of food.
Another emerging crop is aquaculture, or fish farming. Where in the past this was largely a subsistence pursuit, in recent years aquaculture has become a lucrative business. But perhaps just as concerning, in terms of environmental costs, is the fact that it has become a serious competitor in regions where farmed fish are favored by the consumer. A recent review by the Food and Agriculture Organization of the United Nations of global aquaculture production found that as populations grow, so does production, especially for more developed countries. Because many farmed fish are bred for meat rather than eggs, a single large-scale farm can produce more than the meat equivalent of 2 million eggs. Farmed fish are often finned or de-headed, a practice that further reduces environmental sustainability. Fish are also fed on over-processed feed, with the by-product of the process being phosphorus pollution, a highly toxic component of fertilizer. Moreover, some species of farmed fish can accumulate large amounts of toxic substances, such as methylmercury, a by-product of some farms."Fish are among the most bioaccumulative of all food substances," explains Suzanne DeStefano, a research fellow at Duke University's Nicholas School of the Environment, noting that some fish contain more than 20 percent methylmercury.
Unfortunately, there are some estimates that aquaculture takes up around two-thirds of the land that can be used for food production. One aquaculture expert, Phil Clifford, cites Indonesia and China as examples of countries where fish farming, like livestock and crop farming, is in a race to meet demand. Between the fact that these countries already have relatively high rates of fish consumption and that people in other areas of the world prefer to eat more land-intensive fish, Clifford fears that aquaculture may take-up more and more of the available land. "When you have a very large population," he says, "eating livestock and raising fish can become almost a panacea." The waste products of aquaculture, too, are a problem. As much as 90 percent of what is consumed by fish goes into wastewater, which is in turn released into the local environment. "There is no reason why you would keep fish alive in dirty water," Clifford says.
Then there is the matter of the oceans, which fish farms are not a huge part of. Despite their growing abundance, marine fish farms are still an insignificant portion of global aquaculture. There are few benefits to a wild ocean. But there are also few costs. "Fish farming, when well managed, uses a lot less energy and water than agriculture," says DeStefano. "The only downside is that fish is a lot