[YeGoblynQueenne]

Like others have commented below GMOs (well, GMO crops specifically) were not the main driver of the Green Revolution. So the question remains- what are the harms that can come about by not using GMOs?

My understanding is that, at this point in time, the harms are primarily financial. For instance, when the EU imposed a moratorium on GMO crops, the reaction was primarily for countries that, until then, sold GMO crops to EU countries, to complain to the WTO about trade agreement violations- in other words, their financial interests were damaged.

As to issues of food security and feeding the people of developed nations, as I understand it, there is an ongoing debate on whether GMO crops are really needed to achieve this, or whether better management of existing agricultural resources, or better distribution of current food production, can do the job. In other words- GMOs may be beneficial, so not necessary, therefore not using them would not lead to harm.

[bluGill]

No, the harms are environmental. Spraying weed killers (ie glyphosate) uses much less carbon than the mechanical methods. Tractors pulling something through the soil need a lot of fuel. A sprayer running over the same field spraying a gallon of glyphosate uses much less fuel. If you have any concern about global warming you should demand that only GMO crops be grown.

Note that I work for John Deere. We sell to farmers who are both for and against GMO so I'm not supposed to have a bias, but I still need to make this connection clear.