Some researchers at Purdue decided to see what US agriculture would look like if we banned GMO's. Since GMO's produce more crop with fewer inputs, they allow us to increase production without using too much land. If we banned GMOs and wanted to produce the same amount of crops, we would have to convert a lot of land from forest or other wild areas to agriculture, and they say the result would be an increase of "7-17% of global agricultural emissions." And that's just from converting the US! Food prices would also increase, costing consumers $14-24 billion per year.
Another paper from the same conference estimated the value of a variety of insecticides. They found that neonicotinoids (you know, the pesticides suspected of contributing to the big bee die-off?) saved farmers about $1.43 billion in 2013. Bt corn saved $1.3 billion. So, one way to help the bees might be to actually promote GMOs.
Hm, now I know why Whole Foods promotes all that anti-GMO literature: guess who benefits if food prices increase? Hint: farmers get just a few cents of every dollar spent....