This question was answered by Kevin Folta on 10/13/13. He has provided an updated response below. https://gmoanswers.com/ask/i-am-interested-learning-more-about-how-biotech-seeds-improve-sustainability-can-you-provide
Sustainability is an important topic to anyone involved in agriculture. Let’s talk about sustainability on several levels, as “sustainability” means different things to different people.
Toward environmental sustainability, the GM insect tolerant crops allow much less broad-spectrum insecticide to be used, which has many advantages. Insect populations are more diverse, and abundant, except for those that directly harm the crop. Herbicide tolerant crops use a tiny amount (about ¾ of a liter per acre) of a low-environmental-impact herbicide that is relatively safe for humans to apply, and it breaks down quickly in the environment. It also has been shown that those of the herbicide-tolerant varieties decrease the need for tilling, leading to better topsoil retention.
Economic sustainability means a positive net balance between the cost of production and the value of the product. The best example is perhaps the Hawaiian papaya. Papaya farmers find the GMO papaya much more sustainable than non-GM, virus sensitive varieties. Yields are much better and there’s less need for insect controls. On the large agronomic farm the use of herbicide-tolerant and insect resistant crops decreases fuel and labor costs, while generally keeping yields the same or improving slightly. These are all positives in the area of economic sustainability.
There is so much more that can be done for sustainability. The most exciting innovations remain to be realized. There are new plants that require less water, a huge step in sustainability. There are plants that use fertilizers more efficiently. That’s good too from an economic and environmental standpoint.
We are seeing beautiful examples of effects on sustainability in the developing world. A nice example is the Bt Brinjal (eggplant). Farmers do not need to use insecticide, or at least cut back a lot on insecticide use, because they are using this product in Bangladesh. GM cotton has been a great success in many areas of India, increasing revenues for families that use it, and decreasing the number of insecticide treatments required in a growing season.
Sustainable food production boils down to maximizing output while minimizing inputs. The use of GM crops certainly has contributed to this equation and will continue to do so, as more strategies will be developed and deployed in the upcoming years.
Herbicide-tolerant crops have encouraged farmers to practice no-till farming. In conventional farming, the fields are plowed ("tilled") to control weeds. Because of the superior weed control from GM crops, farmers now have to till much less often. This has led to improved soil health and water retention, reduced runoff, and reduced greenhouse gas emissions from agriculture. (National Academy of Sciences, Impact of Genetically Engineered Crops on Farm Sustainability in the United States, 2010) http://www.nap.edu/catalog.php?record_id=12804
Insect-resistant crops have greatly reduced the amount of insecticide that has to be applied to insect-protected crops. It’s estimated that an astounding 600 million pounds LESS active ingredient of insecticide has been used in the United States because of the use of GM crops, significantly reducing farmers’ costs and environmental footprint. (Brookes and Barfoot, Key environmental impacts of global GM crop use 1996-2011, in GM Crops and Food, 4/26/2013) http://www.pgeconomics.co.uk/pdf/2013globalimpactstudyfinalreport.pdf)
In developing countries, the increased production from GM seeds has allowed small farmers to generate more income off of the same amount of land, thus reducing the practice of cutting down forest for more cropland.
The greatest gains are yet to come. GM plants with more efficient use of nitrogen and other important nutrients mean less fertilizer will be needed, saving farmers money, and less fertilizer ends up in the environment. As mentioned previously, GM plants are available to withstand moderate water deficits. In the near future these same traits may allow the same yields or better while consuming less water. Such technologies have been demonstrated as effective in the laboratory and in field contexts.
Going forward, as we apply what we learning about organic, low-input and sustainable production practices to GM crops, we’ll see comparable or improved performance with less cost and environmental impact.