In 1996, Greenpeace calculated that a phase out of methyl bromide in 1998 with a 50% cut in 1997 was the best option in environmental terms - approximately a six year earlier recovery in the ozone layer, and about 14% less ozone loss than under current controls.
Alternatively, phasing out methyl bromide in 2001, with 25% cut in 1998, controls on quarantine and pre-shipment uses and allowing for a 10 year delay for developing countries would accelerate recovery by six years, and lower ozone loss by around 10%.
Quarantine and pre-shipment uses of MeBr are estimated to be over 18% of global consumption (TEAP 1997, p.119). Although relatively small at present they are growing steadily and unless controlled could have a major impact on ozone depletion within several decades. As an example, even if methyl bromide is phased out globally in 2001, the ozone layer will fail to recover if quarantine and pre-shipment uses remain uncontrolled. The increase in ozone depletion, above the base case, would be several hundred percent.