There are several ways that GMOs are harmful to the environment. First, herbicide-resistant crops resulted in a massive increase in the use of herbicides like glyphosate (a probable carcinogen) because they can spray to kill the weeds and not worry about damaging the crops. The increase of herbicide-resistant crops is creating a rapid increase in superweeds that are resistant to herbicide leading to farmers having to do more tillage (which erodes the soil) and use even stronger herbicides.These herbicides hurt the animals and then get into the water. Another problem is that the widespread use of GMOs is destroying crop biodiversity. For example, the U.S. has lost 6,000 out of 7,000 of its apple varieties.This is detrimental to our agriculture and the ecosystem.
GMOs result in less tillage (which removes nutrients from the soil and causes erosion) to address weeds since the crops are herbicide-resistant. GMOs are also good for the environment because they use fewer pesticides and waste less water. Modifying crops to be pest-resistant means that there is less need to use pesticides. These pesticides are harmful to the environment and to animals such as honeybees and monarch butterflies. Crops can also be modified to be drought resistant which would help to waste less water.
[P1] Herbicide-resistant crops meant that farmers could spray more herbicide to kill weeds. [P2] Weeds became resistant to the herbicide. [P3] Farmers had to use stronger herbicides or do more tillage (which erodes the soil). [P4] These toxic chemicals get into the water and hurt the animals. [P5] GMOs are destroying biodiversity by homogenizing the seeds.
Rejecting the premises
[Rejecting P3] GMOs result in less tillage since the crops are herbicide-resistant.