ENVIRONMENT

The highest reading

Scientists grapple with greenhouse gases

D’ARCY JENISH June 24 1991
ENVIRONMENT

The highest reading

Scientists grapple with greenhouse gases

D’ARCY JENISH June 24 1991

The highest reading

ENVIRONMENT

Scientists grapple with greenhouse gases

By drilling hundreds of feet into Antarctic glaciers and removing core samples of ice, scientists have been able to measure the changes in the levels of carbon dioxide (C02) present in the Earth’s atmosphere over the past 160,000 years. According to Barry Smit, a University of Guelph, Ont., geographer, current levels of C02, a gas that some scientists say is contributing to a warming of the Earth’s atmosphere, are higher than at any time during the past 1,600 centuries. Speaking at a conference in Toronto on world climate change last week, Smit warned that increases in global temperatures could raise ocean levels and cause catastrophic flooding of such coastal cities as Cairo and Vancouver. He added that the short-term prospects for stopping global warming, by securing an international agreement that would sharply reduce the amount of carbon in the world’s atmosphere, appear to be slim. Said Smit: “Our institutions are not well designed to manage global change on such a scale.” Organized by the Washington-based Climate Institute, a privately funded environmental advocacy group, the conference brought together experts on global warming from more than a dozen countries, including Finland, Indonesia and Turkey. The principal topic at the meeting was the potential impact of climate change on municipalities and the measures that civic governments can take to reduce its effects. In an

opening address to 194 delegates, Smit said that as a result of concern about global warming, dozens of similar international conferences now are held every year to discuss the issue. But Smit said that stopping or reversing the trend will be a complex task requiring unprecedented international co-operation.

Indeed, negotiations on a global agreement aimed at reducing the airborne pollutants responsible for the so-called greenhouse effect, which most scientists say is responsible for global warming, began last February in Washington, and a second round of talks was scheduled to be held this week in Geneva. Douglas Russell, director of the Environment Canada office that is co-ordinating Canadian participation in the United Nations-sponsored discussions, said that representatives of more than 100 countries were expected to attend the Geneva meeting. At least three more bargaining sessions will be held in an attempt to complete an agreement in time for the UN Conference on Environment and Development next June. The conference, which has been dubbed the “Earth Summit,” will be held in four Brazilian cities, including Rio de Janeiro and Brasilia.

Russell said that Ottawa wants a comprehensive agreement that would include specific targets and schedules for reducing emissions of C02 and other so-called greenhouse gases. At the Washington meeting in February, the par-

ticipating nations spent almost 10 days discussing the procedures for drafting an agreement. They also established two working groups, one that will try to set international commitments for reducing greenhouse gases as well as funding and technology transfers for developing countries, and a second to spell out how those commitments would be fulfilled. Russell said that in Geneva, the working groups would try to begin drafting an agreement. Smit told the delegates at the Toronto conference that scientists have found convincing evidence to support the theory that the greenhouse effect is raising world temperatures. According to this theory, gases such as

C02, a waste product created by burning fossil fuels including oil, natural gas and coal, collect in the upper atmosphere. Those gases trap heat that would otherwise bounce off the planet’s surface and escape from the Earth’s atmosphere. Smit said that atmospheric levels of C02 now have reached concentrations of 353 parts per million—a 24-per-cent increase over the amount of C02 present in the atmosphere in 1700, prior to the industrial age.

Many of the scientists, environmentalists and municipal officials attending the Toronto conference proposed solutions to temperature change that municipalities could apply. Hashem Akbari, a research scientist at the Lawrence Berkeley Laboratories in Berkeley, Calif., described a phenomenon known as urban heat islands. He said that on summer days, the temperature in a city may be five Celsius degrees higher than in the surrounding countryside. Akbari added that if global temperatures rise as predicted during the next 50 years, cities could become increasingly unpleasant places to live in. He said that one way of reducing urban temperatures would be to paint asphalt surfaces white to reflect heat.

While most environmental scientists accept the theory that global warming is occurring, they also concede that solving the problem will require fundamental changes in national economies. Smit noted that some scientists estimate that a reduction of more than 60 per cent in emissions of greenhouse gases would allow global temperatures to stabilize at current levels. “The issue is closely interwoven with our daily lives,” said Smit. “How do you bring about a reduction of two-thirds in emissions from automobiles?” He added that such developing nations as China, India and Brazil reserve the right to exploit their natural resources, including forests and petroleum reserves, even if that contributes to the greenhouse effect. Clearly, reaching any kind of consensus on global warming will be a matter for all leaders of the globe.

D’ARCY JENISH