1. Graham Brookes, Farzad Taheripour, and Wallace E. Tyner
The Contribution of Glyphosate to Agriculture and Potential Impact of Restrictions on Use at the Global Level
Graham Brookes, Farzad Taheripour, and Wallace E. Tyner
PG Economics, Dorchester, UK
Purdue University, Department of Agricultural Economics
International Consortium on Applied Bioeconomy and Research (ICABR) Annual Meeting
University of Berkeley
May 30 to June 2, 2017

2. Outline Background, Research objective and methods, Farm level method,
Farm level impacts,
Economy-wide modeling framework,
Economy-wide impacts,
Conclusions.

3. Background (1)
The International Agency for Research on Cancer (IARC) of the World Health Organization re-evaluated the potential carcinogenic risk to humans of several pesticides, including glyphosate in 2015.
IARC concluded that glyphosate belongs in a 2A category as probably carcinogenic to humans.
As a result of this ‘re-classification’, a number of governments’ may/are considering establishing restrictions or limits on the use of glyphosate.

4. Background (2)
A global ban on the use of glyphosate will encourage farmers in several countries to move away from Genetically Modified (GM) Herbicide Tolerant (HT) crops and shift to conventional non-GM HT seed technology.
The ban could:
Generate major economic losses at farm, national, and global levels,
Lead to reductions in crop production and higher food prices.
The ban could also cause adverse environmental impacts:
Increases in the amount of herbicide active ingredient usage, measured by the EIQ index,
Reversal of soil carbon emission savings associated with GM HT crops,
Increases in emissions due using more fuels in crop production.

5. Background (3)
Glyphosate is widely used in agriculture in many countries across uses
It is a key part of the production system that uses GM HT technology.
This technology allows for the ‘over the top’ spraying of GM HT crops with the broad-spectrum herbicide glyphosate, that targets both grass and broad-leaved weeds but does not harm the crop itself.
GM HT crops have been grown on a widespread commercial basis since 1996
In 2015, the global cultivation reached 150 million hectares, 150 times the 1996 level.
The number of countries adopting this technology increased from 3 in 1996 to 13 in 2015.
The United States is the leading user of this technology

6. Research objectives and methods
This paper evaluates the global economic and environmental impacts associated with the loss of glyphosate in GM HT crops using two different approaches in parallel.
The first approach examines the farm level and aggregate impacts from the removal of the benefits identified in the global impact studies of Brookes and Barfoot (2017a,b) including:
Increases in production costs and losses in yield and production,
Increases in EIQ index and carbon emissions.
The second approach evaluates the economy-wide impact of losing the GM HT technology due to the ban on the use of glyphosate and the corresponding land use change and associated emissions.

7. Results: Farm level impacts (1)
Farm income gains derived from GM HT crops in 2015 that would be lost if glyphosate was no longer allowed to be used (million USD)

8. Results: Farm level impacts (2)
Impact of changes in the use of herbicides and insecticides from growing GM HT crops in 2015 that would potentially be lost at global scale if glyphosate use was banned

9. Results: Farm level impacts (3)
Annual carbon sequestration impacts if glyphosate use were banned

10. Economy-wide analyses
Structure of GTAP-BIO model: A well-known global multi-regional and multi-sectoral computable general equilibrium economic model

11. Economy-wide analyses: Results (1)
Annual changes in crop production if glyphosate was no longer allowed to be used (1000 metric ton)

12. Economy-wide analyses: Results (2)
Annual welfare losses if glyphosate was no longer allowed to be used (million USD at 2011 prices)

13. Economy-wide analyses: Results (3)
Induced land use changes if glyphosate was no longer allowed to be used (1000 hectares)
Induced land use changes generate 233,563 million kg CO2: Equivalent to the land use emissions induced from the production of 29.5 billion litres of corn ethanol in the US

14. Conclusions
We showed that the loss of glyphosate in GM HT crops will generate the following major economic and environmental impacts:
Farm level:
Reduction in farm income: By $6.7 billion,
Increases in pesticides and herbicides: By 8.16 million kg active ingredients,
Expansion in fuel consumption and emissions: By 2.6 billion kg CO2,
Expansion in emissions due to losses in soil sequestration: By 24 billion kg CO2,
Economy-wide impacts
Reduction in crop production: By more that 15 million metric tons,
Increases in crop prices across the world,
Welfare losses: $7.4 billion at 2011 prices,
Expansion in emissions due to land use changes: By 234 billion kg CO2,

15. Thank you! Questions and Comments tfarzad@purdue.edu