Stephen Leahy

BROOKLIN, Canada, Jun 24 2005 (IPS) — Holes in the ozone layer over the Earth’s polar regions remain dangerously large, even as international efforts to solve the problem are flagging, scientists warn.

The Arctic region suffered its greatest ever loss of stratospheric ozone last winter. Only a change in weather prevented millions of people in the Northern hemisphere from being exposed to significantly higher levels of damaging ultraviolet (UV) radiation.

Ozone depletion has not lessened despite international action through the Montreal Protocol on Substances that Deplete the Ozone Layer, scientists from Cambridge University reported last April in the leading journal Nature.

While ozone expert Peter Hodgson agrees the polar regions are no better off, the amount of ozone-eating chlorofluorocarbons (CFCs) in the lower atmosphere has finally started to decline. However, it will be decades before the ozone layer is restored to levels that existed before the 1970s, Hodgson writes in report published by the British Institute of Physics this month.

“The Montreal Protocol is doing a pretty good job but I think that an element of complacency has crept in,” Hodgson said in a statement.

The Protocol, which was created in 1987, requires the 184 nations involved to phase out the use of CFCs and nearly 100 chemicals that damage the ozone layer, the part of the atmosphere that protects the Earth from UV radiation. Increased levels of UV in recent decades have been linked to higher levels of skin cancer, eye disease and other health problems in humans and many other species.

Thanks to the Protocol, the level of ozone-depleting chlorine in the atmosphere is at or near its peak, but levels of other ozone-depleting substances, such as bromine, are continuing to rise, the report says.

Bromine levels are rising principally because the United States continues to use large amounts of methyl bromide, which turns into bromine in the atmosphere.

Under the Protocol, use of methyl bromide in developed countries was to be completely phased out by Jan. 1, 2005.

Instead U.S. vegetable and fruit growers will use nearly 10 million kilogrammes of the pesticide in 2005. That’s more than the U.S. used in 2002.

Under the Protocol, “critical use exemptions” can be granted that allow countries to continue to use banned substances for a short period of time until they can find a substitute.

Governments are meeting July 1st in Montreal to negotiate the latest phase of the Protocol and the U.S. will once again seek exemptions to use some 9.5 million kilogrammes of methyl bromide in 2006, more than the rest of the developed world combined.

“There are plenty of alternatives to methyl bromide but the U.S. agricultural industry doesn’t want to switch,” says Geeta Ohl of the Environmental Investigation Agency (EIA), an environmental NGO based in London and Washington.

For example, the strawberry industries in California and Florida are lobbying hard to keep using methyl bromide because it’s cheap and easy to use, Ohl told IPS.

Rates of pediatric melanoma – a fatal form of skin cancer – in the United States have more than doubled between 1982 and 2002, according to the EIA. That fact, combined with new science about ozone holes in the Arctic, means it is irresponsible to continue to use a chemical that damages the ozone layer, she says.

The continued abuse of the critical use exemption by the U.S. also makes a mockery of the millions of dollars that have been invested to help developing countries use alternatives to methyl bromide, Ohl said.

“It undermines the intent of phase-out,” agrees Janos Mate of Greenpeace International.

Worse still is that methyl bromide has an immediate impact on the ozone layer and scientists still are not sure how bad that impact is, Mate said in an interview. What is becoming clear is that global warming is making the already damaged ozone layer worse, he said.

Paradoxically, as the Earth warms at the surface and especially in the polar regions, the upper atmosphere is getting colder, creating just the right conditions for chemicals like chlorine and bromine to destroy ozone.

The link between global warming and ozone loss is just starting to be investigated, says Tom McElroy, a senior research scientist and ozone chemistry expert at the Meteorological Service of Canada.

“It (global warming) looks to be the likely explanation for the colder temperatures we’ve seen in the upper atmosphere,” McElroy told IPS.

Cold conditions did severely deplete Arctic ozone this year but warmer temperatures in March prevented the formation of a huge hole, he said. Instead a small hole formed over Greenland and the North Atlantic Ocean.

A large ozone hole could easily blanket parts of the heavily populated regions of the Northern hemisphere and affect millions of people. Just a one or two percent increase in UV intensity is linked to higher risk of skin cancer and eye disease.

“We’re going to have to watch very carefully what’s going on in the Arctic,” he said.

Greenpeace’s Mate says chemicals used to replace CFCs, called hydrochlorofluorocarbons (HCFCs), also have an impact on the ozone layer. A better replacement chemical, hydrofluorocarbons (HFCs), now widely used in home and automobile air conditioners, is ozone-friendly – but it is a potent greenhouse gas.

There are better and safer alternatives, but the chemical industry, which has a powerful lobby at the Montreal Protocol meetings, opposes these, Mate says.

The Protocol is widely considered the most successful international environmental treaty in history. However, nearly 20 years later, the problem is far from solved.

“We should remember that we nearly destroyed our UV shield,” says Mate.

Sadly, there is no sense of urgency anymore about the threats to the ozone layer, he warned.