ENVIRONMENT

The poles in peril

Ontario takes the lead in protecting the ozone layer

RIC DOLPHIN February 27 1989
ENVIRONMENT

The poles in peril

Ontario takes the lead in protecting the ozone layer

RIC DOLPHIN February 27 1989

The poles in peril

ENVIRONMENT

Ontario takes the lead in protecting the ozone layer

When American scientist Thomas Midgley demonstrated his newly developed refrigerant in 1930, he inhaled a lungful of the gas and then blew out a candle to show how safe the new product was. But by the 1970s, Midgley’s family of gases, which are known as chlorofluorocarbons (CFCs) and which are widely used as refrigerator coolants, plastic foams and aerosol sprays, were recognized as being far from benign. Scientists said that CFCs escaping into the atmosphere were destroying the Earth’s ozone layer—a gaseous barrier nine to 22 miles above the Earth’s surface, which filters out many of the sun’s harmful ultraviolet rays. In 1985, scientists discovered a hole in the ozone layer above the Antarctic. And last week, scientists confirmed that the ozone over the Arctic is undergoing similar destruction.

Scientists say that as the ozone layer erodes, the increasing penetration of ultraviolet rays may increase skin cancer among human beings and destroy crops and marine life. “We have to take this seriously,” said Ivar Isaksen, a Norwegian meteorologist at the University of Oslo, who was part of a group of 150 U.S., British and European scientists who studied the upper Arctic atmosphere this winter. “The ozone layer over the Arctic is increasingly breaking down.”

For his part, Wayne Evans, a Toronto-based atmospheric scientist with Environment Canada—who was part of a team that studied the ozone layer from Alert, N.W.T., this winter— said that when temperatures in the Arctic fall below -78°C, clouds of nitric acid ice form. That ice in turn converts hydrochloric acid from the accumulated CFCs into chlorine. Then, when the sun warms the ice clouds, the released chlorine erodes the ozone. He added, “We began to notice a bite out of the ozone layer just as though a Pac-Man had been at work.” Some environmentalists say that the holes in the ozone layer show that stronger measures are needed to control the use of CFCs. Under the 1987 Montreal Protocol, 24 nations, including Canada, agreed to reduce production of CFCs by 50 per cent by 1999. Last week, the government of Ontario went a step further by proposing a law that would ban the use of CFCs by 1998. If the alarming depletion of atmospheric ozone continues, other jurisdictions will likely decide to follow Ontario’s example.

RIC DOLPHIN