You see a lot of criticism about “politically correct” shopping — people love to sneer at the idea that buying the wrong kind of shoes or paper or food makes a difference. But it does, or at least it can. The New York Times has a current op-ed (free registration required) called “Did your shopping list kill a songbird” that illustrates this point. It says:
Since the 1980s, pesticide use has increased fivefold in Latin America as countries have expanded their production of nontraditional crops to fuel the demand for fresh produce during winter in North America and Europe. Rice farmers in the region use monocrotophos, methamidophos and carbofuran, all agricultural chemicals that are rated Class I toxins by the World Health Organization, are highly toxic to birds, and are either restricted or banned in the United States. In countries like Guatemala, Honduras and Ecuador, researchers have found that farmers spray their crops heavily and repeatedly with a chemical cocktail of dangerous pesticides.
The piece goes on to discuss the (proven) bad effects the chemicals have on birds. It also mentions a really sad New Yorker article from a year or two ago, that is also worth a read if you can find it.