Take them away, and suddenly you're getting less food per acre of land. According to some guy who won a Nobel Prize, we could feed 4 billion people if we went all organic. This sounds great except maybe to the 2.5 billion people who would be left without anything to eat.
A tiny fraction of the people organic food would leave starving.
Despite all the claims that chemicals used in farming are bad for us, it turns out cancer rates have dropped 15 percent since farmers began using chemicals. How is that possible? Well it's mainly due to people being able to afford more fruits and vegetables, because the chemicals allow more to be grown. That's one reason the average life expectancy in the US went up by almost 10 years between 1950 and 2000.
As for the environment, it turns out organic farming has its own issues. Because it is much less efficient, there is actually a shortage of organic food available. This leads to people having the food shipped in from much further away. We're no scientists, but we think that doing things like shipping organic milk 900 miles over the highway in a truck belching diesel fumes is probably canceling out any environmental benefits you might have gained from going organic.
Oh, and did we mention organic farming uses a lot of manure to fertilize crops? This results in a greater risk of contamination. Although organic produce only accounts for one percent of the food supply, it accounts for eight percent of the E. coli cases in the U.S.
Basically, you are at greater risk of eating a shit sandwich, which is admittedly organic, but still.