We’ve doused the world in pesticides. Is that a problem?
Pesticides have become an enduring feature of modern life. In 2007, the world used more than 5.2 billion pounds of weed killers, insecticides, and fungicides to do everything from protecting crops to warding off malaria.
But that’s also led many researchers to wonder what sorts of broader impacts all these chemicals are having. The latest issue of Science includes a fascinating special section devoted to the world’s pesticide use. I’ll pull out a few good charts and highlights of interest:
1) Pesticide use is on the rise almost everywhere, with some key exceptions:
Note that pesticide sales in North America haven’t grown very much — and use is actually declining in the United States (more on that below). The growth in Europe, meanwhile, is largely driven by a big uptick in Eastern Europe. Meanwhile, sales are basically stagnant in the Middle East and Africa.
2) There’s a surprisingly large variation in how farmers in different countries use pesticides:
Of the 2.4 billion kilograms of pesticides used in 2007, the United States accounted for about 20 percent of the total. But notice that American farmers are relatively sparing in their use of pesticides — using just 2.2 kilograms per hectare of arable land. Compare that with China, where farmers are “less trained” and the figure is more like 10.3 kilograms per hectare.
Of course, the skill level of farmers is just one variable here. Pesticide use is also particularly high in countries with “valuable crops where pest pressures are high, including Colombian coffee and Dutch tulips.” And use is low in Africa largely because of the high cost.
<snip>
4) And insecticides have been invaluable in controlling malaria.
One recent study estimated that the growing use of insecticide-treated mosquito nets prevented the deaths of some 842,800 children between 2001 and 2010. The catch? “Insecticide resistance in the mosquito threatens those gains,” the Science issue notes.
<snip>
7) Scientists are developing all sorts of complex ways to reduce the world’s dependence on pesticides, though sometimes simpler solutions work pretty well.
The chart above shows how overall pesticide use in the United States has declined 0.6 percent each year between 1980 and 2007. And it’s dropped even faster in corn fields — in part because of the widespread use of Bt corn, a genetically modified breed of corn that’s supposed to be toxic to pests. One hitch? There’s now some evidence that certain pests are becoming resistant to the Bt corn, especially in areas where it’s used heavily. That could lead to a resurgence in pesticide use.
Or perhaps researchers will come up with new strategies. The Science issue outlines on some of the other clever ideas in the works: “New synthetic chemicals to protect crops hold the promise of stronger and more specific protection with less collateral damage. And some crops won’t need pesticides at all: Scientists are developing plants whose immune systems can ward off fungal, bacterial, or viral diseases, and they are using RNA interference to help plants fight insects—a new technology that could hit the market before the decade ends.”
Then again, sometimes low-tech ideas work pretty well too. One piece points out that a soap-opera-led campaign in Vietnam helped convince local rice farmers not to overuse pesticides. And in Australia, farmers are now using non-chemical control techniques, such as burning seeds, to control a massive weed problem that was brought on, in part, by herbicide overuse.
<snip>
More charts and info: http://wapo.st/18DCo7n
A lot of damage has been done and cannot be reversed. In addition, new methods are going to run into the 'The Law Of Unintended Consequences.'
= new reply since forum marked as read
