Saving the Ozone Layer: Alternatives to Methyl Bromide

One of the main threats to the Earth's ozone layer today is a potent pesticide called methyl bromide that plays a pivotal role in Southern cash-crop economies. However, a recent report by Friends of the Earth, an international environmental organization, suggests that viable alternatives to methyl bromide exist and can be adopted at minimal cost to producers.

The report, entitled The Technical and Economic Feasibility of Replacing Methyl Bromide in Developing Countries, presents the results of an international research project that examined methyl bromide use patterns in Zimbabwe, Thailand and Chile; compared the costs and yields of alternatives; identified the most technically feasible ones, where possible; and assessed the barriers and opportunities for adopting cost-effective substitutes. The study was funded by the International Development Research Centre (IDRC), the US Environmental Protection Agency, Environment Canada, Swiss Agency for Development and Cooperation, Friends of the Earth USA, Friends of the Earth Canada, and Agriculture and Agri-Food Canada.

Highly toxic fungicide

Methyl bromide is a highly toxic fungicide and the second most widely applied pesticide in the world. It is primarily used on "high value" export crops bound for North America, European, and East Asian markets, such as tomatoes, peppers, grapes, strawberries, tobacco and flowers. Methyl bromide is also used to protect stored grains. The pesticide is effective against a wide range of pests including insects, worms, and pathogenic microorganisms.

However, methyl bromide has a dramatic environmental impact. After being sprayed on crops, the pesticide drifts into the upper atmosphere where it damages the ozone layer, which blocks ultraviolet (UV) rays from reaching the Earth's surface. Although a shorter-lived substance than chlorofluorocarbons (CFCs) — a better-known family of ozone-depleting compounds — methyl bromide destroys ozone molecules at 50 times the rate of CFCs. In a 1994 scientific assessment, the World Meteorological Organization concluded that phasing out this chemical is the single largest step that governments can take to protect the ozone layer.

Phase-out schedules

In 1995, industrialized countries agreed to phase out their production and consumption of methyl bromide by the year 2010, under the United Nations Montreal Protocol on Substances that Deplete the Ozone Layer. However, Southern nations have been more reluctant to commit to phase-out schedules, because of the importance of this chemical to their agricultural economies. The dilemma faced by Southern exporters is that foreign markets will only import agricultural commodities that have been treated for pests and pathogens.

The study found that in Zimbabwe, methyl bromide is used on 98% of the nation's tobacco crop, which had an export value of US$530 million in 1994-95. The pesticide is also used to grow flowers, paprika, fruits and vegetables. In Chile, methyl bromide is mainly used on tomatoes and peppers.

Replacing methyl bromide

The Friends of the Earth report noted that there is no single replacement for methyl bromide, but rather a variety of options, depending on the crop or application. For some fruit and vegetable crops, farmers could adopt a system of integrated pest management involving tools such as pest-resistant plant varieties, crop rotation, natural plant-based pesticides, and beneficial microbes. In other cases, steam treatment may be more appropriate. Studies have shown that this technique — which involves heating water to 150 degrees Celsius and applying it to soils — can be as effective as methyl bromide, at half the price.

For shipping purposes, the report recommends the use of controlled atmospheres that filter all of the gases found in air except nitrogen, thus killing insects by asphyxiation. Other options include the use of hot water dips, steam, hot dry air, or cold treatments for protection against fungal and other infestations.

Environmental and economic benefits

The report suggests that the adoption of alternatives to methyl bromide would not only benefit the environment but may also generate economic growth. "One of the major opportunities is the development of new industries in developing countries to supply local and export markets with alternative products and services," it states.

Jacinda Fairholm is a student and member of the Canadian Environmental Network Youth Caucus, who lives in Vancouver.

Human and Economic Costs of Ozone Depletion

Resource Persons:

Beatrice Olivastri, Friends of the Earth Canada, 47 Clarence Street, Suite 306, Ottawa, Ontario, K1N 9K1, Canada; Tel: (613) 241-0085, ext. 24; Fax: (613) 241-7998; E-mail: foe@intranet.ca

Melanie Miller, Environmental Policy Analyst, New Zealand; E-mail: m-miller@ramhb.co.nz

Miquel Stuzin, INIA Agricultural Research Institute, Santiago, Chile; E-mail: info@codeft.mic.cl

Anne Shonfield, Methyl Bromide Alternative Network and Pesticide Action Network, 116 New Montgomery No. 810, San Francisco, CA, 94105, USA; Tel: (415) 541-9140; Fax: (415) 541-9253; E-mail: panna@igc.apc.org

Kelly Sims, Ozone Action Inc., 1621 Connecticut Ave NW, Washington DC, 20009, USA; Tel: (202) 265-6738; Fax: (202) 332-4865; E-mail: ozone_action@essential.org

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Links to explore ...

Related IDRC articles and publications:

Integrated Pest Management for Colombian Small Farmers, by David Mowbray

Return to Resistance: Breeding Crops to Reduce Pesticide Dependence

Women and Integrated Pest Management

Additional resources:

Campaign Against Methyl Bromide: Ozone-killing Pesticide Opposed

Methyl Bromide

Methyl Bromide and Stratospheric Ozone Depletion

The Ozone Secretariat WWW Home Page

Selected References on Pesticides and Pest Management

IDRC Reports is published weekly on-line by the International Development Research Centre.
Its aim is to keep an international readership informed about the work IDRC supports in developing countries as well as other development issues of interest.

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Updated April 11, 1997. Please send your comments to editor of Reports.