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October 2005, Volume 11, Number 4


Brazil is mechanizing its cane harvest, largely to avoid the environmental effects of burning cane fields for hand harvesters. Cane plants form serrated leaves that must be burned to avoid injuring cane cutters- the fire does not damage the sugar, which is in the cane or stalk.

The government and mills in Sao Paulo, Brazil's main cane state, have agreed to eliminate manual cutting of the crop by 2021, with 50 percent machine harvested by 2011. Every machine eliminates 80 cutting jobs, but thousands of cutters earn about 800 reais ($340) a month, twice the minimum wage, for up to eight months a year.

Venezuela is one of the most urbanized countries in Latin America, with 90 percent of the country's 25 million residents living in cities. Land ownership is concentrated, with five percent of residents owning about 75 percent of arable land. Under a 2001 land reform law, the government wants to induce poor urban residents to return to the countryside under a land reform that declares some land idle and makes it available to peasant farmers. Private landowners, some of whose land was acquired before Venezuela gained independence in 1848, say that the government should give up some of its 17 million acres before redistributing private land to coops in which individual farmers do not get title to the land they farm.

Mexico in 2002 imposed a 20 percent tax on soft-drink bottlers who use US corn sweeteners to protect its sugar industry, and in August 2005, the World Trade Organization agreed with the US that the tax violates free trade laws. Mexico's sugar industry is inefficient, producing sugar that costs $0.25 a pound, more than twice world levels, but supports 2.4 million well-organized Mexicans. In 2001, the Fox administration nationalized Mexico's 56 sugar mills and established minimum prices, and in 2002 added the tax to protect the industry.

As 9,000 Israelis withdrew from the Gaza strip in August 2005, American donors paid $14 million for about 90 percent of the 1,000 acres of greenhouses in Gush Katif, the main settlement cluster in Gaza, in order to turn them over to the Palestinians. The greenhouses, which consume large amounts of water, were heavily subsidized by the Israeli government, and generated sales of about $75 million a year with the help of 3,500 Palestinian migrants.

Avian Flu. Avian flu (influenza A/H5N1), which originated in the southeastern China, has spread to southeast Asia and Russia's far east. The 1957 Asian flu that spread rapidly around the world was a hybrid of bird and human flu viruses, but the current avian flu appears to be more deadly. Of the 112 people who have been infected with the A/H5N1 flu, more than half died, which is a much higher fatality rate than for the Spanish flu of 1918-19 that killed at least 50 million people.

Influenza viruses invade cells lining the throat and windpipe, where they replicate and cause inflammation but are eventually suppressed by the immune system. A/H5N1 strains, unlike most flus, have proteins that can trigger replication in many organs, including the liver, intestines and brain that lead to a whole-body infection. Simultaneously, a second "defect" in A/H5N1 unleashes a storm of immune-system chemicals called cytokines that, in excessive amounts, can cause lethal damage to the body's own tissues.

If A/H5N1 develops the capacity to spread easily from one person to another, there could be a pandemic. Influenza A's are simple viruses that get what they need to replicate from the cells they invade, but are adaptable because their genes are carried on eight unconnected strands, called "gene segments." If two different viruses find themselves in the same cell, these segments can be traded in a process called reassortment, producing a new virus, which appears to be what happened in the case of A/H5N1.

Waterfowl such as ducks are reservoirs of A/H5N1 influenza strains. There are two billion domestic ducks in East Asia. Thailand systematically checked its ducks in November 2004, killing those inflected with the A/H5N1 influenza. However, A/H5N1 is now circulating in several species of migratory birds capable of carrying the virus to India, Australia and Central Asia. A mutated form of the bird flu that could by spread by humans could cause a pandemic, and the US government is scrambling to develop vaccines.

John Barry, author of The Great Influenza, a book about the 1918-19 flu pandemic that killed an estimated 50 million people worldwide, including 675,000 in the United States, says that the US is not yet prepared for another flu pandemic. In 1918, most of those who died fell ill in the first 24 weeks of the pandemic, before governments were prepared to respond. The US government, for example, refused to cancel events celebrating the end of World War I, which allowed the flu to spread rapidly at public events.

Fisheries. An analysis of 50 years of fish caught by Japanese ocean-going ships found that the diversity of fish species has declined by 50 percent since the 1950s. On land, warm areas are generally richest in diversity, but in the ocean, fish diversity is highest in subtropical areas, where temperatures average about 77 degrees Fahrenheit and fronts of warmer and cooler water come together and cause plankton and small fish to collect. Where water is warmer or colder, fish diversity drops.

Some say that the world may be about to experience "a gathering wave of ocean extinctions" as scores of species of ocean-dwelling fish, birds and mammals edge toward extinction. The science is imprecise because ocean dwellers are harder to track and some produce so many offspring they seem invulnerable. The culprits, according to experts, are the industrialization of the fishing industry after World War II, a global boom in ocean-front development and a rise in global temperatures. Ocean fish catches tripled between 1950 and 1992, and the bycatch from huge nets often includes slow-growing species.

David Brown, "Scientists Race To Head Off Lethal Potential Of Avian Flu," Washington Post, August 23, 2005.