The global income and production effects of genetically modified (GM) crops 1996–2011

Abstract

A key part of any assessment of the global value of crop biotechnology in agriculture is an examination of its economic impact at the farm level. This paper follows earlier annual studies which examined economic impacts on yields, key costs of production, direct farm income and effects and impacts on the production base of the four main crops of soybeans, corn, cotton and canola. The commercialization of genetically modified (GM) crops has continued to occur at a rapid rate, with important changes in both the overall level of adoption and impact occurring in 2011. This annual updated analysis shows that there have been very significant net economic benefits at the farm level amounting to $19.8 billion in 2011 and $98.2 billion for the 16 year period (in nominal terms). The majority (51.2%) of these gains went to farmers in developing countries. GM technology have also made important contributions to increasing global production levels of the four main crops, having added 110 million tonnes and 195 million tonnes respectively, to the global production of soybeans and maize since the introduction of the technology in the mid-1990s.

Keywords: :

• yield
• cost
• income
• production
• genetically modified crops

Introduction

Although the first commercial genetically modified (GM) crops were planted in 1994 (tomatoes), 1996 was the first year in which a significant area of crops containing GM traits was planted (1.66 million hectares). Since then there has been a significant increase in plantings and by 2011, the global planted area reached over 148 million hectares.

Since the mid-1990s, there have been many papers assessing the economic impacts associated with the adoption of this technology, at the farm level. The authors of this paper have, since 2005, engaged in an annual exercise to aggregate and update the sum of these various studies, and where possible and appropriate, to supplement this with new analysis. The aim of this has been to provide an up to date and as accurate as possible assessment of some of the key economic impacts associated with the global adoption of GM crops. It is also hoped the analysis contributes to greater understanding of the impact of this technology and facilitates more informed decision making, especially in countries where crop biotechnology is currently not permitted.

Therefore, integrating the data for 2011 into the context of earlier developments, this study updates the findings of earlier analysis into the global economic impact of GM crops since their commercial introduction in 1996. Earlier analysis by the current authors has been published in various journals, including AgbioForum¹, the International Journal of Biotechnology² and GM Crops.³ The methodology and analytical procedures in this present discussion are unchanged to allow a direct comparison of the new with earlier data. Readers should however, note that some data presented in this paper are not directly comparable with data presented in previous analysis because the current paper takes into account the availability of new data and analysis (including revisions to data for earlier years).

In order to save readers the chore of consulting these earlier papers for details of the methodology and arguments, the journal’s editors have agreed that these elements may again be included in full in this updated paper.

The analysis concentrates on farm income effects because this is a primary driver of adoption among farmers (both large commercial and small-scale subsistence). It also quantifies the (net) production impact of the technology. The authors recognize that an economic assessment could examine a broader range of potential impacts (e.g., on labor usage, households, local communities and economies).

However, these are not included because undertaking such an exercise would add considerably to the length of the paper and an economic assessment of wider economic impacts would probably merit a separate assessment in its own right.

Results and Discussion

HT crops

The primary impact of GM HT (largely tolerant to the broad spectrum herbicide glyphosate) technology has been to provide more cost effective (less expensive) and easier weed control for farmers. Nevertheless, some users of this technology have also derived higher yields from better weed control (relative to weed control obtained from conventional technology). The magnitude of these impacts varies by country and year and is mainly due to prevailing costs of different herbicides used in GM HT systems vs. conventional alternatives, the mix and amount of herbicides applied, the cost farmers pay for accessing the GM HT technology and levels of weed problems. The following important factors affecting the level of cost savings achieved in recent years should, however, be noted:

• In the period 2008–2009, the average cost associated with the use of GM HT technology globally increased relative to earlier years because of the significant increase in the global price of glyphosate relative to changes in the price of other herbicides commonly used on conventional crops. This has abated since 2009 with a decline in the price of glyphosate to previous historic trend levels;

• The amount farmers pay for use of the technology varies by country. Pricing of technology (all forms of seed and crop protection technology) varies according to the level of benefit that farmers are likely to derive from it. In addition, it is influenced by intellectual property rights (patent protection, plant breeders’ rights and rules relating to use of farm-saved seed). In countries with weaker intellectual property rights, the cost of the technology tends to be lower than in countries where there are stronger rights. This is examined further in c) below;

• Where GM HT crops (tolerant to glyphosate) have been widely grown, some incidence of weed resistance to glyphosate has occurred. This has been attributed to how glyphosate was used; because of its broad-spectrum post-emergence activity, it was often used as the sole method of weed control. This approach to weed control put tremendous selection pressure on weeds and as a result contributed to the evolution of weed populations predominated by resistant individual weeds. It should, however, be noted that there are hundreds of resistant weed species confirmed in the International Survey of Herbicide Resistant Weeds (www.weedscience.org). Worldwide, there are 24 weed species that are currently (accessed February 2013) resistant to glyphosate, compared with 129 weed species resistant to ALS herbicides and 70 weed species resistant to triazine herbicides. In addition, it should be noted that the adoption of GM HT technology has played a major role in facilitating the adoption of no and reduced tillage production techniques in North and South America. This has also probably contributed to the emergence of weeds resistant to herbicides like glyphosate and to weed shifts toward those weed species that are not well controlled by glyphosate. As a result, growers of GM HT crops are increasingly being advised to include other herbicides (with different and complementary modes of action) in combination with glyphosate in their integrated weed management systems. At the macro level, these changes have already begun to influence the mix, total amount, cost and overall profile of herbicides applied to GM HT crops. Relative to the conventional alternative, however, the economic impact of the GM HT crop use has continued to offer important advantages. Also, many of the herbicides used in conventional production systems had significant resistance issues themselves in the mid-1990s. This was, for example, one of the reasons why glyphosate tolerant soybeans were rapidly adopted, as glyphosate provided good control of these weeds. If the GM HT technology was no longer delivering net economic benefits, it is likely that farmers around the world would have significantly reduced their adoption of this technology in favor of conventional alternatives. The fact that GM HT global crop adoption levels have not fallen in recent years suggests that farmers must be continuing to derive important economic benefits from using the technology.

These points are further illustrated in the analysis below.

GM HT soybeans

The average impacts on farm level profitability from using this technology are summarized in Table 1. The main farm level gain experienced has been a reduction in the cost of production, mainly through reduced expenditure on weed control (herbicides). Not surprisingly, where yield gains have occurred from improvements in the level of weed control, the average farm income gain has tended to be higher, in countries such as Romania, Mexico and Bolivia. A second generation of GM HT soybeans became available to commercial soybean growers in the US and Canada in 2009. This technology offered the same tolerance to glyphosate as the first generation (and the same cost saving) but with higher yielding potential. The realization of this potential is shown in the higher average farm income benefits (Table 1).

Table 1. GM HT soybeans: summary of average farm level economic impacts 1996–2011 ($/hectare)

Country	Cost of technology	Average farm income benefit (after deduction of cost of technology)	Type of benefit	References
1st generation GM HT soybeans
Romania (to 2006 only)	50–60	104	Small cost savings of about $9/ha, balance due to yield gains of +13% to +31%	Brookes (2005^4) Monsanto Romania (2007^5)
Argentina	2–4	23 plus second crop benefits of 193	Cost savings plus second crop gains	Qaim and Traxler (2005^6) Trigo and CAP (2006^7) and updated from 2008 to reflect herbicide price changes
Brazil	16–25	37	Cost savings	Parana Department of Agriculture (2004^8) Galveo (2010,^9 2012^10)
USA	15–39	38	Cost savings	Marra et al. (2002^11) Carpenter and Gianessi (2002^12) Sankala and Blumenthal (2003^13 and 2006^14) Johnson and Strom (2008^15) And updated to reflect herbicide price and common product usage
Canada	20–40	20	Cost savings	George Morris Center (2004^16) and updated to reflect herbicide price and common product usage
Paraguay	4–10	18 plus second crop benefits of 193	Cost savings	Based on Argentina as no country-specific analysis identified. Impacts confirmed by industry sources and herbicide costs updated 2009 onwards from herbicide usage survey data (AMIS Global)
Uruguay	2–4	19	Cost savings	Based on Argentina as no country-specific analysis identified. Impacts confirmed by industry sources and herbicide costs updated 2009 onwards from herbicide usage survey data (AMIS Global)
South Africa	20–30	4	Cost savings	Based on Argentina as no country-specific analysis identified. Impacts confirmed by industry sources and herbicide costs updated 2009 onwards from herbicide usage survey data (AMIS Global)
Mexico	20–25	49	Cost savings plus yield gain in range of +2% to +13%	Monsanto unpublished annual monitoring reports and personal communications
Bolivia	3–4	81	Cost savings plus yield gain of +15%	Fernandez W et al. (2009^17)
2nd^t generation GM HT soybeans
US and Canada	50–65	120	Cost savings as first generation plus yield gains in range of +5% to +10%	As first generation GM HT soybeans plus farm level survey data from Monsanto USA

Notes: (1) Romania stopped growing GM HT soybeans in 2007 after joining the European Union, where the trait is not approved for planting. (2) The range in values for cost of technology relates to annual changes in the average cost paid by farmers. It varies for reasons such as the price of the technology set by seed companies, exchange rates, average seed rates and values identified in different studies. (3) For additional details of how impacts have been estimated, see examples in Supplemental Materials, Appendix 1.

GM HT soybeans have also facilitated the adoption of no tillage production systems, shortening the production cycle. This advantage has enabled many farmers in South America to plant a crop of soybeans immediately after a wheat crop in the same growing season. This second crop, additional to traditional soybean production, has added considerably to farm incomes and to the volumes of soybean production in countries such as Argentina and Paraguay.

Overall, in 2011, GM HT technology in soybeans has boosted farm incomes by $3.89 billion and since 1996 has delivered $32.2 billion of extra farm income. Of the total cumulative farm income gains from using GM HT soybeans, $10.6 billion (33%) has been due to yield gains/second crop benefits and the balance, 67%, has been due to cost savings.

GM HT maize

The adoption of GM HT maize has mainly resulted in lower costs of production, although yield gains from improved weed control have arisen in Argentina, Brazil and the Philippines (Table 2).

Table 2. GM HT maize: summary of average farm level economic impacts 1996–2011 ($/hectare)

Country	Cost of technology	Average farm income benefit (after deduction of cost of technology)	Type of benefit	References
USA	15–30	20	Cost savings	Carpenter and Gianessi (2002^12) Sankala and Blumenthal (2003^13 and 2006^14) Johnson and Strom (2008^15) Also updated to reflect herbicide price and common product usage
Canada	17–35	11	Cost savings	Monsanto Canada (personal communications) and updated annually since 2008 to reflect changes in herbicide prices and usage
Argentina	16–20	84	Cost savings plus yield gains over 10% and higher in some regions	Personal communication from Monsanto Argentina, Grupo CEO and updated since 2008 to reflect changes in herbicide prices and usage
South Africa	10–18	1	Cost savings	Personal communication from Monsanto South Africa and updated since 2008 to reflect changes in herbicide prices and usage
Brazil	17–20	77	Cost savings plus yield gains of +1% to +4%	Galveo (2010^9 and 2012^10)
Colombia	38–40	17	Cost savings	Mendez et al. (2011^18)
Philippines	24–29	47	Cost savings plus yield gains of +5% to +15%	Gonsales et al. (2009^19) Monsanto Philippines (personal communications) Updated since 2010 to reflect changes in herbicide prices and usage

(1) The range in values for cost of technology relates to annual changes in the average cost paid by farmers. It varies for reasons such as the price of the technology set by seed companies, exchange rates, average seed rates and values identified in different studies. (2) For additional details of how impacts have been estimated, see examples in Supplemental Materials, Appendix 1.

In 2011, the total global farm income gain from using this technology was $1.54 billion, with the cumulative gain over the period 1996–2011 being $4.21 billion. Within this, $0.76 billion (18%) was due to yield gains and the rest derived from lower costs of production.

GM HT cotton

The use of GM HT cotton delivered a net farm income gain of about $167 million in 2011. Over the 1996–2011 period, the total farm income benefit was $1.22 billion. As with other GM HT traits, these farm income gains have mainly arisen from cost savings (87% of the total gains), although there have been some yield gains in Brazil, Mexico and Colombia (Table 3).

Table 3. GM HT cotton summary of average farm level economic impacts 1996–2011 ($/hectare)

Country	Cost of technology	Average farm income benefit (after deduction of cost of technology)	Type of benefit	References
USA	13–82	22	Cost savings	Carpenter and Gianessi (2002^12) Sankala and Blumenthal (2003^13 and 2006^14) Johnson and Strom (2008^15) Also updated to reflect herbicide price and common product usage
South Africa	15–32	33	Cost savings	Personal communication from Monsanto South Africa and updated since 2008 to reflect changes in herbicide prices and usage
Australia	32–131	27	Cost savings	Doyle et al. (2003^20) Monsanto Australia (personal communications) and updated to reflect changes in herbicide usage and prices
Argentina	17–30	39	Cost savings	Personal communication from Monsanto Argentina, Grupo CEO and updated since 2008 to reflect changes in herbicide prices and usage
Brazil	45–52	118	Cost savings plus yield gains of +2% to +4%	Galveo (2010^9 and 2012^10)
Mexico	29–66	132	Cost savings plus yield gains of +3% to +18%	Monsanto Mexico annual monitoring reports^21 and personal communications
Colombia	96–184	100	Cost savings plus yield gains of +4%	Monsanto Colombia annual personal communications

(1) The range in values for cost of technology relates to annual changes in the average cost paid by farmers. It varies for reasons such as the price of the technology set by seed companies, exchange rates, average seed rates, the nature and effectiveness of the technology (eg, second generation ‘Flex’ cotton offered more flexible and cost effective weed control than the earlier first generation of HT technology) and values identified in different studies. (2) For additional details of how impacts have been estimated, see examples in Supplemental Materials, Appendix 1.

Other HT crops

GM HT canola (tolerant to glyphosate or glufosinate) has been grown in Canada, the US and more recently Australia, while GM HT sugar beet is grown in the US and Canada. The farm income impacts associated with the adoption of these technologies are summarized in Table 4. In both cases, the main farm income benefit has derived from yield gains. In 2011, the total global income gain from the adoption of GM HT technology was $479 million and cumulatively since 1996, it was been $3.31 billion.

Table 4. Other GM HT crops summary of average farm level economic impacts 1996–2011 ($/hectare)

Country	Cost of technology	Average farm income benefit (after deduction of cost of technology)	Type of benefit	References
GM HT canola
US	12–33	59	Mostly yield gains of +1% to +12% (especially Invigor canola)	Sankala and Blumenthal (2003^13 and 2006^14) Johnson and Strom (2008^15) And updated to reflect herbicide price and common product usage
Canada	18–32	49	Mostly yield gains of +3% to +12% (especially Invigor canola)	Canola Council (2001^22) Gusta et al. (2009^23) and updated to reflect herbicide price changes and seed variety trial data (on yields)
Australia	32–41	61	Mostly yield gains of +16% to +22% (where replacing triazine tolerant canola)	Monsanto Australia (2009^24)
GM HT sugar beet
US and Canada	130–151	118	Mostly yield gains of +3% to +13%	Kniss (2008^25) Khan (2008^26) Armstrong JJQ and Sprague C (2010^27) Annual updates of herbicide price and usage data

Notes: (1) In Australia, one of the most popular type of production has been canola tolerant to the triazine group of herbicides (tolerance derived from non GM techniques). It is relative to this form of canola that the main farm income benefits of GM HT (to glyphosate) canola has occurred. (2) InVigor’ hybrid vigour canola (tolerant to the herbicide glufosinate) is higher yielding than conventional or other GM HT canola and derives this additional vigour from GM techniques. (3) The range in values for cost of technology relates to annual changes in the average cost paid by farmers. It varies for reasons such as the price of the technology set by seed companies, exchange rates, average seed rates and values identified in different studies. (4) For additional details of how impacts have been estimated, see examples in Supplemental Materials, Appendix 1.

GM IR crops

The main way in which these technologies have impacted on farm incomes has been through lowering the levels of pest damage and hence delivering higher yields (Table 5).

Table 5. Average (%) yield gains GM IR cotton and maize 1996–2011

	Maize insect resistance to corn boring pests	Maize insect resistance to rootworm pests	Cotton insect resistance	References
US	7.0	5.0	9.8	Carpenter and Gianessi (2002^12) Marra et al. (2002^11) Sankala and Blumenthal (2003^13 and 2006^14) Hutchison et al. (2010^28) Rice (2004^29)
China	N/a	N/a	10.0	Pray et al. (2002^30) Monsanto China (personal communications)
South Africa	11.8	N/a	24.0	Gouse et al. (2005,^31 2006a^32 and 2006b^33) Van der Wald (2010^34) Ismael et al. (2002^35) Kirsten et al. (2002^36) James (2003^37)
Honduras		N/a	N/a	Falk Zepeda et al. (2009^38)
Mexico	N/a	N/a	10.0	Traxler et al. (2001^39) Monsanto Mexico annual cotton monitoring reports^21
Argentina	6.4	N/a	30.0	Trigo (2002^40) Trigo and Cap (2006^7) Qaim and De Janvry (2002^41 and 2005^42) Elena (2001^43)
Philippines	18.6	N/a	N/a	Gonsales (2005^44) Yorobe (2004^45) Ramon (2005^46)
Spain	9.9	N/a	N/a	Brookes (2003^47 and 2008^48) Gomez-Barbero and Rodriguez-Corejo (2006^49) Riesgo et al. (2012^50)
Uruguay	5.6	N/a	N/a	As Argentina (no country-specific studies available and industry sources estimate similar impacts as in Argentina)
India	N/a	N/a	38.0	Bennett et al. (2004^51) IMRB (2006^52 and 2007^53) Herring and Rao (2012^54)
Colombia	21.0	N/a	10.0	Mendez et al. (2011^18) Zambrano et al. (2009^55)
Canada	7.0	5.0	N/a	As US (no country-specific studies available and industry sources estimate similar impacts as in the US)
Burkina Faso	N/a	N/a	18.0	Vitale J et al. (2008^56 and 2010^57)
Brazil	12.0	N/a	-0.3	Galveo (2009,^58 2010^10 and 2012^59) Monsanto Brazil (2008^60)
Pakistan	N/a	N/a	13.0	Nazli et al. (2010^61)
Burma	N/a	N/a	31.0	USDA (2011^62)
Australia	N/a	N/a	Nil	Doyle (2005^63) James (2002^64) CSIRO (2005^65) Fitt (2001^66)

Notes: N/A = not applicable

The greatest improvement in yields has occurred in developing countries, where conventional methods of pest control have typically been least effective (e.g., reasons such as less well developed extension and advisory services, lack of access to finance to fund use of crop protection application equipment and products), with any cost savings associated with reduced insecticide use being mostly found in developed countries. These effects can be seen in the level of farm income gains that have arisen from the adoption of these technologies, as shown in Table 6.

Table 6. GM IR crops: average farm income benefit 1996–2011 ($/hectare)

Country	GM IR maize: cost of technology	GM IR maize (average farm income benefit (after deduction of cost of technology)	GM IR cotton: cost of technology	GM IR cotton (average farm income benefit (after deduction of cost of technology)
US	17–32 IRCB, 22–42 IR CRW	80 IRCB, 86 IR CRW	26–58	80
Canada	17–25 IRCB, 22–42 IR CRW	82 IRCB 99 IR CRW	N/a	N/a
Argentina	20–33	20	27–86	177
Philippines	30–39	88	N/a	N/a
South Africa	8–17	78	14–50	185
Spain	17–51	156	N/a	N/a
Uruguay	20–33	20	N/a	N/a
Honduras	30–31	86	N/a	N/a
Colombia	43–48	233	50–172	67
Brazil	54–69	12	34–52	15
China	N/a	N/a	38–60	341
Australia	N/a	N/a	85–299	193
Mexico	N/a	N/a	48–59	190
India	N/a	N/a	17–54	267
Burkina Faso	N/a	N/a	51–54	157
Burma	N/a	N/a	17–20	349
Pakistan	N/a	N/a	14–15	47
Average across all user countries		75		244

Notes: (1) GM IR maize all are IRCB unless stated (IRCB = insect resistance to corn boring pests), IRCRW = insect resistance to corn rootworm. (2) The range in values for cost of technology relates to annual changes in the average cost paid by farmers. It varies for reasons such as the price of the technology set by seed companies, the nature and effectiveness of the technology (eg, second generation ‘Bollgard’ cotton offered protection against a wider range of pests than the earlier first generation of ‘Bollgard’ technology), exchange rates, average seed rates and values identified in different studies. (3) Colombia, GM IR maize are farm level trials only. (4) Average across all countries is a weighted average based on areas planted in each user country. (5) N/A = not applicable

At the aggregate level, the global farm income gains from using GM IR maize and cotton in 2011 were $7.1 billion and $6.56 billion respectively. Cumulatively since 1996, the gains have been $25.8 billion for GM IR maize and $31.3 billion for GM IR cotton.

Aggregated (global level) impacts

At the global level, GM technology has had a significant positive impact on farm income, with in 2011, the direct global farm income benefit being $19.8 billion. This is equivalent to having added 6.2% to the value of global production of the four main crops of soybeans, maize, canola and cotton. Since 1996, farm incomes have increased by $98.2 billion.

At the country level, US farmers have been the largest beneficiaries of higher incomes, realizing over $43.6 billion in extra income between 1996 and 2011. This is not surprising given that US farmers were first to make widespread use of GM crop technology and for several years the GM adoption levels in all four US crops have been in excess of 80%. Important farm income benefits ($22 billion) have occurred in South America (Argentina, Bolivia, Brazil, Colombia, Paraguay and Uruguay), mostly from GM technology in soybeans and maize. GM IR cotton has also been responsible for an additional $25.7 billion additional income for cotton farmers in China and India.

In 2011, 51.2% of the farm income benefits were earned by farmers in developing countries. The vast majority of these gains have been from GM IR cotton and GM HT soybeans. Over the 16 years, 1996–2011, the cumulative farm income gain derived by developing country farmers was $49.63 billion, equal to 50.5% of the total farm income during this period.

The cost to farmers for accessing GM technology, across the four main crops, in 2011, was equal to 21% of the total value of technology gains. This is defined as the farm income gains referred to above plus the cost of the technology payable to the seed supply chain. Readers should note that the cost of the technology accrues to the seed supply chain including sellers of seed to farmers, seed multipliers, plant breeders, distributors and the GM technology providers.

In developing countries, the total cost was equal to 14% of total technology gains compared with 28% in developed countries. While circumstances vary between countries, the higher share of total technology gains accounted for by farm income in developing countries relative to developed countries reflects factors such as weaker provision and enforcement of intellectual property rights in developing countries and the higher average level of farm income gain per hectare derived by farmers in developing countries compared with those in developed countries.

Crop production effects

Based on the yield impacts used in the direct farm income benefit calculations above and taking account of the second soybean crop facilitation in South America, GM crops have added important volumes to global production of corn, cotton, canola and soybeans since 1996 (Table 7).

Table 7. Additional crop production arising from positive yield effects of GM crops

	1996–2011 additional production (million tonnes)	2011 additional production (million tonnes)
Soybeans	110.2	12.74
Corn	195.0	34.54
Cotton	15.85	2.48
Canola	6.55	0.44
Sugar beet	0.45	0.13

Note: Sugar beet, US and Canada only and from 2008

The GM IR traits, used in maize and cotton, have accounted for 97.3% of the additional maize production and 99.4% of the additional cotton production. Positive yield impacts from the use of this technology have occurred in all user countries (except for GM IR cotton in Australia where the levels of Heliothis sp (boll and bud worm pests) pest control previously obtained with intensive insecticide use were very good. The main benefit and reason for adoption of this technology in Australia has arisen from significant cost savings and the associated environmental gains from reduced insecticide use) when compared with average yields derived from crops using conventional technology (such as application of insecticides and seed treatments). The average yield impact across the total area planted to these traits over the 16 y since 1996 has been +10.1% for maize and +15.8% for cotton.

As indicated earlier, the primary impact of GM HT technology has been to provide more cost effective (less expensive) and easier weed control, as opposed to improving yields, the improved weed control has, nevertheless, delivered higher yields in some countries. The main source of additional production from this technology has been via the facilitation of no tillage production systems, shortening the production cycle and how it has enabled many farmers in South America to plant a crop of soybeans immediately after a wheat crop in the same growing season. This second crop, additional to traditional soybean production, has added 106.4 million tonnes to soybean production in Argentina and Paraguay between 1996 and 2011 (accounting for 96.6% of the total GM-related additional soybean production).

Conclusion

During the past 16 years, the adoption of crop biotechnology (by 15.4 million farmers in 2011) has delivered important economic benefits. The GM IR traits have mostly delivered higher incomes through improved yields in all countries. Many farmers, especially in developed countries, have also benefited from lower costs of production (less expenditure on insecticides). The gains from GM HT traits have come from a combination of effects. The GM HT technology-driven farm income gains have mostly arisen from reduced costs of production, though in South America, it facilitated the move away from conventional to low/no-tillage production systems and enabled many farmers to plant a second crop of soybeans after wheat in the same season.

Over reliance on the use of glyphosate and the lack of crop rotation by some farmers, in some regions, has contributed to the development of weed resistance. As a result, farmers are increasingly adopting a mix of reactive and proactive weed management strategies incorporating a mix of herbicides. This has added cost to the GM HT production systems compared with several years ago, although relative to the conventional alternative, the GM HT technology continues to offer important economic benefits in 2011.

Overall, there is a considerable body of evidence, in peer reviewed literature and summarized in this paper, that quantifies the positive economic impacts of crop biotechnology. The analysis in this paper therefore provides insights into the reasons why so many farmers around the world have adopted and continue to use the technology. Readers are encouraged to read the peer reviewed papers cited, as well as the many others who have published on this subject (and listed in the references below), and to draw their own conclusions.

Methodology

The report is based on extensive analysis of existing farm level impact data for GM crops, much of which can be found in peer reviewed literature. While primary data for impacts of commercial cultivation were not available for every crop, in every year and for each country, a substantial body of representative research and analysis is available and this has been used as the basis for the analysis presented. In addition, the authors have undertaken their own analysis of the impact of some trait-crop combinations in some countries (notably GM herbicide tolerant (HT) traits in North and South America) based on herbicide usage and cost data over the last five years.

As indicated in earlier papers, the economic impact of this technology at the farm level varies widely, both between and within regions/countries. Therefore the measurement of impact is considered on a case by case basis in terms of crop and trait combinations and is based on the average performance and impact recorded in different crops by the studies reviewed. Where more than one piece of relevant research (e.g., on the impact of using a GM trait on the yield of a crop in one country in a particular year) has been identified, the findings used in this analysis reflect the authors assessment of which research is most likely to be reasonably representative of impact in the country in that year. For example, there are many papers on the impact of GM insect resistant (IR) cotton in India. Few of these are reasonably representative of cotton growing across the country, with many papers based on small scale, local and unrepresentative samples of cotton farmers. Only the reasonably representative research has been drawn on for use in this paper—readers should consult the references to this paper to identify the sources used.

This approach may still both, overstate, or understate, the impact of GM technology for some trait, crop and country combinations, especially in cases where the technology has provided yield enhancements. However, as impact data for every trait, crop, location and year data are not available, the authors have had to extrapolate available impact data from identified studies to years for which no data are available. In addition, if the only studies available took place several years ago, there is a risk that basing current assessments on comparisons from several years ago may not adequately reflect the nature of currently available alternative (non GM seed or crop protection) technology. The authors acknowledge that these factors represent potential methodological weaknesses. Therefore to reduce the possibilities of over/understating impact due to these factors, the analysis:

• Directly applies impacts identified from the literature to the years that have been studied. As a result, the impacts used vary in many cases according to the findings of literature covering different years. Examples where such data are available include the impact of GM insect resistant (IR) cotton: in India [see Bennett R et al. (2004⁵¹), IMRB (2006)⁵² and IMRB (2007)],⁵³ in Mexico [see Traxler et al. (2001)³⁹ and Monsanto Mexico (2005, 2007, 2008)²¹] and in the US [see Sankala and Blumenthal (2003¹³ and 2006¹⁴), Mullins and Hudson (2004)⁶⁷]. Hence, the analysis takes into account variation in the impact of the technology on yield according to its effectiveness in dealing with (annual) fluctuations in pest and weed infestation levels;

• Uses current farm level crop prices and bases any yield impacts on (adjusted – see below) current average yields. In this way a degree of dynamic has been introduced into the analysis that would, otherwise, be missing if constant prices and average yields identified in year-specific studies had been used;

• As indicated above, it includes some changes and updates to the impact assumptions identified in the literature based on new papers, annual consultation with local sources (analysts, industry representatives, databases of crop protection usage and prices) and some “own analysis” of changes in crop protection usage and prices;

• Adjusts downwards the average base yield (in cases where GM technology has been identified as having delivered yield improvements) on which the yield enhancement has been applied. In this way, the impact on total production is not overstated.

Detailed examples of how the methodology has been applied to the calculation of the 2011 years results are presented in Supplemental Materials, Appendix 1. Supplemental Materials, Appendix 2 also provides details of the impacts and assumptions applied and their sources.

Other aspects of the methodology used to estimate the impact on direct farm income are as follows:

• Where stacked traits have been used, the individual trait components were analyzed separately to ensure estimates of all traits were calculated. This is possible because the non-stacked seed has been (and in many cases continues to be) available and used by farmers and there are studies that have assessed trait-specific impacts;

• All values presented are nominal for the year shown and the base currency used is the US dollar. All financial impacts in other currencies have been converted to US dollars at prevailing annual average exchange rates for each year (source: United States Department of Agriculture Economics Research Service);

• The analysis focuses on changes in farm income in each year arising from impact of GM technology on yields, key costs of production (notably seed cost and crop protection expenditure but also impact on costs such as fuel and labor. Inclusion of these costs is, however, more limited than the impacts on seed and crop protection costs because only a few of the papers reviewed have included consideration of such costs in their analysis. Therefore in most cases the analysis relates to impact of crop protection and seed cost only, crop quality (e.g., improvements in quality arising from less pest damage or lower levels of weed impurities which result in price premia being obtained from buyers) and the scope for facilitating the planting of a second crop in a season (e.g., second crop soybeans in Argentina following wheat that would, in the absence of the GM HT seed, probably not have been planted). Thus, the farm income effect measured is essentially a gross margin impact (impact on gross revenue less variable costs of production) rather than a full net cost of production assessment. Through the inclusion of yield impacts and the application of actual (average) farm prices for each year, the analysis also indirectly takes into account the possible impact of GM crop adoption on global crop supply and world prices.

The paper also includes estimates of the production impacts of GM technology at the crop level. These have been aggregated to provide the reader with a global perspective of the broader production impact of the technology. These impacts derive from the yield impacts and the facilitation of additional cropping within a season (notably in relation to soybeans in South America). Details of how these values were calculated (for 2011) are shown in Supplemental Materials, Appendix 1.

Acknowledgments

Graham Brookes and Peter Barfoot are agricultural economists with PG Economics UK Ltd, specialists in assessing the impact of new technology in agriculture. The authors acknowledge that funding toward the researching of this paper was provided by Monsanto. The material presented in this paper is, however, the independent views of the authors; it is a standard condition for all work undertaken by PG Economics that all reports are independently and objectively compiled without influence from funding sponsors.

Disclosure of Potential Conflicts of Interest

No potential conflict of interest was disclosed.