There are natural sources of methyl bromide release including net releases from oceans, soil and plants. It is however generally agreed that methyl bromide added to the atmosphere as a result of human activity can significantly upset the delicate environmental balance in the stratosphere. New Zealand is a signatory and meets its treaty obligations through the Ozone Layer Protection Act 1996. The figure for 2003 will be 75 percent of the 1991 consumption, with a complete phase-out by 2005. General use by developing countries is controlled by a longer phase-out programme.
Research is underway, however, to find alternatives.
Soil sterilisation trials using steam have proved just as effective as methyl bromide and reportedly at less cost. Fumigators in New Zealand are mixing chloropicrin with methyl bromide in an effort to minimise methyl bromide consumption. Possible chemical alternatives include 1,3-dichloropropene, basamid , chloropicrin, metam sodium, selective contact insecticides and fungicides. Organic amendments, crop rotation, plant extracts, changed management practices, changed cultural practices, heat, biological controls, and plant breeding are all possible non-chemical alternatives. However depending on the crops to be treated and the pests requiring control, alternatives will most likely involve a combination of both chemical and non-chemical controls.