Dear EarthTalk: Is it true that bananas are taboo for anyone who is concerned about rainforest destruction? Even if I seek out "fair trade" or organic bananas, am I feeding the demand which is causing rainforest to be cleared?
—Laura Barnard, Hillsboro, OH
Sadly, the short answers to these questions may be yes and yes for now, but that may change as the $5 billion banana industry slowly comes to terms with greener forms of production. Historically, growing the world's most popular fruit has caused massive degradation of rainforest land across the tropics, spread noxious chemicals throughout formerly pristine watersheds, and poisoned and exploited farm workers.
"Banana plantations were infamous for their environmental and social abuses, which included the use of dangerous pesticides, poor working conditions, water pollution and deforestation," reports the Rainforest Alliance, a New York-based non-profit that has been working to improve worker and environmental conditions in the industry since 1990. "Pesticide-impregnated plastic bags, which protect bananas as they grow, often littered riverbanks and beaches near banana farms, while agrochemical runoff and erosion killed fish, clogged rivers and choked coral reefs." Also, the proximity of housing to banana fields, coupled with lax regulations for pesticide handling, led to frequent illness among workers and people living near the plantations.
But help is on the way, largely thanks to the pioneering work of the Rainforest Alliance, which certifies as sustainable those banana farms and plantations that meet certain criteria for responsible farm management set by the Sustainable Agriculture Network, a coalition of non-profits striving to improve commodity production in the tropics. As a result of the program, some 15 percent of all bananas sold internationally now come from Rainforest Alliance Certified farms. The group is especially proud of its agreements with two of the largest growers, Favorita and Chiquita. All of Favorita's farms in Ecuador and all of Chiquita's farms in Guatemala, Honduras, Costa Rica and Panama are certified sustainable under the program.
While the Rainforest Alliance's success is certainly a step in the right direction, other groups bemoan the fact that even certified plantations are on land that was once tropical rainforest. According to Rainforest Relief, Americans should still avoid purchasing bananas altogether and instead opt for fruit grown locally, such as apples, peaches, cherries or pears. The group is hopeful, though, that its work with farm cooperatives growing organic bananas under the shade of a diverse forest canopy in Costa Rica can eventually drive the larger international banana market toward better land use and worker safety standards.
"These growers are for the most part farming only small portions of the land they own or control, the rest being left as montaña—undisturbed forest—to keep their flowing water fresh and keep healthy the wildlife that "works" their farms with them," reports Rainforest Relief. The group has been working to develop secondary markets for bananas that may have been bruised during harvest or transport but which can still be used for baby food, vinegar and other applications that don't require unblemished peels. Some of these products are marketed to tourists in Costa Rica while others are sold in the U.S.—look for the Rainforest Farms brand, among others—at Whole Foods and other natural foods retailers.
Dear EarthTalk: Is there any link between increased volcanic activity—such as the recent eruptions in Iceland, Alaska and elsewhere—and global warming?
—Ellen McAndrew, via e-mail
It's impossible to pin isolated natural phenomena—like an individual volcanic eruption—on global warming, but some researchers insist that there is a correlation between the two in some instances.
"Global warming melts ice and this can influence magmatic systems," reports Freysteinn Sigmundsson of the Nordic Volcanological Centre at the University of Iceland. Her research with Carolina Pagli of the University of Leeds in England suggests that rocks cannot expand to turn into magma—the primary "feedstock" for volcanic eruptions—when they are under the pressure of a big ice cap pushing down on them. As the theory goes, melting ice caps relieve that pressure and allow the rocks to become magma. This in turn increases the chances of larger and/or more frequent eruptions in affected regions, from Iceland to Alaska to Patagonia to Antarctica.
As for Iceland specifically, the eruption of Mt. Ejyafjallajñkull that shut down some air travel for weeks this past spring cannot be blamed on changing climate: That volcano lies under a relatively small icecap which would not exert enough pressure to affect the creation of magma. But Sigmundsson and Pagli found that the melting of about a tenth of Iceland's biggest icecap, Vatnajokull, over the last century caused the land to rise an inch or so per year and led to the growth of an underground mass of magma measuring a third of a cubic mile. Similar processes, they say, led to a surge in volcanic eruptions in Iceland at the end of the last ice age, and similarly increased volcanic activity is expected to occur there in the future.
On the flip side, volcanic eruptions can exacerbate the ongoing effects of climate change: Already retreating glaciers can lose all their ice when something below them blows. Of course, many volcanoes around the world are not subject to pressure from ice caps, and scientists stress that there is little if any evidence linking global warming to eruptions in such situations.
Some have theorized that large volcanic eruptions contribute to global warming by spewing large amounts of carbon dioxide and other greenhouse gases into the stratosphere. But the amount of greenhouse gases emitted by even a large and ongoing volcanic eruption is but a drop in the bucket in comparison to our annual output of industrial and automotive carbon emissions.
According to the U.S. Geological Survey, greenhouse gas emissions from volcanoes make up less than one percent of those generated by human endeavors. Also, ash clouds and sulfur dioxide released from volcanoes shield some sunlight from reaching the Earth and as such can have a cooling effect on the planet. The 1991 eruption of Mt. Pinatubo in the Philippines—a much larger eruption than what occurred recently in Iceland—caused an average cooling of half a degree centigrade worldwide during the following year. Regardless, single volcanic eruptions, even if they last for weeks or months, are unlikely to send enough gas or ash up into the skies to have any long term effect on the planet's climate.
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