BERKELEY, CALIF. — Rising levels of trace gases in the atmosphere are increasing the
``greenhouse effect,`` a warming of the Earth that may alter climate, food production and living patterns, a researcher says.
The ``greenhouse effect`` is the expected result of a build-up of carbon dioxide in the atmosphere that, like a greenhouse, allows passage of light but prevents heat radiated off the planet`s surface from escaping into outer space.
Carbon dioxide is produced by burning coal and other fossil fuels.
The warming has already started, but only to a tiny degree. The Environmental Protection Agency warned in October, 1983, that any significant rise in the Earth`s temperature could cause enormous disruption, affecting all areas of human activity.
Harold Johnston, of Lawrence Berkeley Laboratory, said new studies indicate the greenhouse effect is being escalated by increased atmospheric methane, nitrous oxides and chlorofluorocarbon compounds, such as those used to propel aerosol sprays.
``The calculated increase in Earth`s surface temperature due to the increase of these trace gases over the last 10 years is as much as 70 percent of that due to carbon dioxide,`` said Johnston, a chemist with the laboratory`s Materials and Molecular Research Division.
``Studying the effects of trace atmospheric gases on the ozone layer led to a significant realization with regards to methane, nitrous oxides and the chlorofluorocarbons,`` he said.
``As far as the ozone layer is concerned, there are some cancellations between the effects of increasing the amounts of these gases in the atmosphere so that the net effect on ozone is close to zero. But such increases all move in one direction on the greenhouse effect--all act to raise surface temperature.``
The public should not panic, however, he said.
``The indications are that over the next 100 years, Earth`s surface temperature will be higher as a result of the human enterprises than it would otherwise be,`` Johnston said.