Water is a precious resource and every effort must be made to save water to avert the critical global shortages that are foreseen for both industrial and developing countries in the imminent future. The importance of saving water, through every conceivable means, cannot be overstressed because it is the single most important resource in agriculture. Water will become increasingly more limited in the future in both industrial and developing countries as urbanization continues and the demand for water in agriculture continues to increase. A recent IFPRI Report (2002), “Global Water Outlook to 2025: An Impending Crisis” predicts that if the current water crisis continues, water constraints could lead to a reduction of 350 million MT of grain in 2025 which is more than current US annual grain production. As a result, global prices of rice could increase by 40%, wheat by 80%, and maize by 120 % if current demand trends continue.

To put water savings, resulting from reduced insecticide applications into context, it is instructive to consider the minimal water requirements of people as well as the availability of water. A minimum basic requirement of 50 liters per person per day has been proposed to satisfy the basic requirements of drinking, sanitation, bathing and cooking (Glieck 1996). About 55 countries with a combined population of 1 billion failed to meet this minimal standard in 1995. Countries differ significantly in water usage for agriculture; for example, in Africa 88% of the fresh water is used for agriculture compared with 86% in Asia, but only 33% in Europe. In Africa per capita consumption of water is 47 liters per day compared with 85 liters in Asia, 334 liters in the UK, and 578 liters in the US (Johns Hopkins University 2002). Two thirds of the global population obtains its water from public standpipes, wells and other public water sources. In the developing countries much of the water has to be carried over long distances, usually by women and girls.

On a global basis the world consumed 1,799 cubic km of fresh water in 1995, and this is expected to increase to 2,081 cubic km by 2025 (IFPRI 2002). Agriculture is the major consumer of water, using approximately 70% of the fresh water drawn for human use (Engelman and Leroy 1993). Increasing production on irrigated land is critical because even though only 17 % of crop land is irrigated it produces 30 to 40 % of total crop production globally. In the future, agriculture will require significantly more water for irrigation, as irrigated land is expected to increase by 11% by 2025 (IFPRI 2002). Given that agriculture accounts for 70% of all water used for human use, it follows that the greatest opportunity for potential savings is also in agricultural uses. Irrigation is the biggest consumer of water in agriculture and is obviously the key area for achieving savings through increased efficiency. Reducing the considerable volume of water used for applying pesticides, through the use of crops such as Bt cotton, represents a new opportunity to save water which only materialized following the large scale adoption of GM crops in 1996.

The volume of water used per single ground application of insecticide is in the range of 5 to 10 gallons per acre (Williams 2002c). The calculation below uses an average of 7.5 gallons/acre, equivalent to 70 liters/hectare which is conservative, considering estimates from South Africa of 118 liters of water/hectare (Ismael et al 2002a) for knapsack spraying, which usually requires higher water volumes, than the larger tractor drawn sprayers. Some cotton insecticides are applied by air (up to 50% in US), when less water is used (2.5 gals/acre or 23 liters/hectare). However, on a global scale most cotton insecticide is applied by ground sprayers, with a high percentage applied at higher volumes by powered or hand operated knapsack sprayers by small farmers in developing countries where approximately 70% of cotton is grown.

Small farmers in developing countries have to laboriously carry water for spraying over long distances in harrowing conditions wasting time and effort which could be used much more effectively for more important family duties that are often neglected because of lack of time. The deployment of 4.3 million hectares of Bt cotton globally in 2001 is estimated to have saved 1.7 billion liters of water. This resulted from using 10,627 MT less insecticides (a.i.) used at 0.45 kg a.i./hectare translates to 23.9 million fewer spray-hectares at 70 liters/hectare = 1.7 billion liters of water. For the five million small farmers in developing countries who are currently growing Bt cotton, there has also been an enormous saving of effort for men, women and children who otherwise would have labored unnecessarily to carry water and suffered the additional critical ill-effects from spraying insecticides to control cotton insect pests.

Global potential savings in water from reduced insecticide sprayings from the extended adoption of Bt can be estimated as follows: 81,000,000 kg (a.i.) of cotton insecticide used globally at an average of 0.45 kg/hectare/spray in 2001 translates to 180 million spray-hectares; this is consistent with a global average of approximately 5.5 sprays applied on 33.5 million hectares = 185 million spray-hectares. The amount of water used to apply 81,000,000 kg of a.i. is 180 million spray-hectares x 70 liters = 12.6 billion liters or 3.3 billion US gallons. Potential annual global water savings, from utilizing Bt cotton would reduce insecticide use by half, is estimated at 6.3 billion liters (of which 1.7 billion liters has already been saved) or approximately 1.8 billion US gallons. This significant saving of 6.3 billion liters is considered a conservative estimate given that the water volume used in the calculation is 70 liters/hectare/spray whereas estimates from developing countries are as high as 118 liters/hectare/spray (Ismael et al 2002a). To put this saving into context, 6.3 billion liters would supply a city of 1.5 million people in Africa, with their per capita consumption of 47 liters per day of water, for approximately 3 months.

To put a human face on the social benefits that Bt cotton offers as a result of its reduced requirement for water for insecticides sprays, the following scenario is typical for a woman farmer growing conventional cotton on a resource-poor farm in the Makhathini Flats in South Africa. She spends one day spraying one hectare of conventional cotton; she has to labor hard to carry water from a source that is at least one kilometer from the field; for a single application for one hectare she has to apply 7 knapsack loads/hectare, each load weighing 16 kg (36lbs), for a total of 118 liters (31 gallons) of water per hectare. Using a powered or hand operated knapsack sprayer, she walks 9 km (5 miles)/hectare sprayed, and she is required to repeat the process up to 11 times a season which takes a total of 11 days of arduous work consuming from 770 to 1,300 liters (200 to 340 gallons) of water per hectare. The average cotton area on a farm in the Makhathini Flats is 1.7 hectares of cotton (Ismael et al 2002a) hence the magnitude of the effort required of women, and the corresponding savings, is 70% more than the above estimates for 1 hectare. With Bt cotton she can reduce the number of sprays from 11 to 4 (Ismael et al 2002a), save 490 to 826 (130 to 218 gallons) liters of water/hectare of cotton, and does not have to walk an extra 60 km or 35 miles. The 7 days per hectare that she saves from using Bt cotton (equivalent to 12 days on the average farm with 1.7 hectares of cotton), can be more usefully devoted to: caring for her children (who often have to help with the intensive spraying for conventional cotton); caring for the sick (AIDS is taking a heavy toll on family members in South Africa); attending to other household duties which currently are often neglected because of the onerous duties of small resource-poor farmers, 50% of whom are women in South Africa. The savings in water and the social benefits associated with Bt cotton are of enormous value to cotton farmers in the developing world who labor hard to survive, and can benefit significantly from the multiple benefits that Bt cotton offers.

In summary, for the average cotton holding of 1.7 hectares of cotton in the Makhathini Flats in South Africa, in a typical season, a woman farmer is relieved of 12 days of arduous spraying, saves over 1,000 liters of water (over 250 US gallons), walks 100 km less, suffers less insecticide poisoning and increases her income significantly by approximately $85/season, through using Bt cotton, rather than conventional cotton.