OTTAWA — The surprising record-breaking hole recently detected in the protective ozone layer above the Arctic highlights the importance of improving — not cutting — monitoring programs, three atmospheric scientists told federal politicians on Tuesday.

Following a breakfast meeting with about three dozen members of Parliament, the scientists said ongoing research over the past two decades has helped the international community make seven different revisions to improve a treaty signed in Montreal in 1987 that restricts substances that deplete the layer, which protects the Earth from the sun's ultraviolet radiation.

Scientists have predicted that the ozone layer could recover from depletion observed in the 1980s by about 2050, but that it remains threatened by new substances not covered by the treaty as well as existing pollution that occurred before the agreement came into force.

"A major thing that was learned this morning is that the issue of ozone depletion is not a solved problem," said Thomas Duck, an atmospheric scientist from Dalhousie University in Halifax. "We certainly understand a lot of things, but the discovery of the Arctic ozone hole really came as a surprise. It was not anticipated, and this past March and April, there it was."

Duck, Kaley Walker from the University of Toronto and Gordon Shepherd from York University in Toronto, were invited to discuss the matter with politicians by Liberal environment critic Kirsty Duncan, who is also a scientist. Duncan said she wanted to promote the discussion to find a non-partisan way to examine the government's plans to "optimize" or "streamline" the way it measures ozone.

Although Conservative and Bloc Quebecois MPs did not attend the session, Duck said he believed the group had a productive discussion about the history of Canada's ozone monitoring efforts and the science.

"It's very hard to predict what's going to happen in the future. Now we have models that give you some kind of idea of what's going to happen as we go forward, but there are also new chemical threats emerging all the time," Duck said.

"We're continually changing this chemical mix in the atmosphere. So I think this is one thing that people really learned this morning is that really the only way we have of understanding whether or not this chemical mix is impacting the ozone layer or whether new chemicals are going to cause more depletion going forward is to take the measurements."

Duck explained that there were two technologies used to measure ozone levels, including one that also can be used to measure the lower atmosphere where ozone is considered to be an air pollutant.

Duncan said she was disappointed that Conservative MPs didn't participate in the session but was pleased with the turnout from her own caucus as well as from the New Democrats and Green party leader Elizabeth May.

"The only way I know how to do business is to work across party lines, but to have 35 MPs (at the morning session) is terrific," she said. "I just hope we'll share this knowledge and we'll keep moving this issue forward."

A spokeswoman for Environment Minister Peter Kent declined to comment.

A spokeswoman for the Bloc, which has four MPs, explained that environment critic Maria Mourani was interested in the topic but unable to attend because she was at a parliamentary committee studying the government's omnibus crime legislation which heard from Quebec Justice Minister Jean-Marc Fournier in the morning.

mdesouza@postmedia.com

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