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The greenhouse effect: Is it here? 



BY NANCY DAVIS 



Imagine the Earth as a giant laboratory. 



In the past century, we've been con- 

 ducting an experiment in our labora- 

 tory. We've burned massive amounts of 

 coal and oil and pumped all the by- 

 products into the sky. 



We called our experiment the In- 

 dustrial Revolution. 



Now, the results of our revolutionary 

 investigation are just coming in. 



And as it turns out, the advances 

 that ushered us into the modern age 

 may have changed the world for man- 

 kind to come. 



Consider the evidence: 



• This year, 30 states had the driest 

 spring in 50 years. 



• This summer, the Midwest suffered 

 through what may have been its 

 worst drought since the dust bowl of 

 1934. 



• The Earth's temperatures for the first 

 five months of 1988 were the 

 warmest on record. 



• And if that's not enough, the four 

 hottest years of the last century have 

 been in the 1980s. 



Could it be that the dreaded green- 

 house effect is here? 



Some scientists believe the evidence 

 is mounting. Others are more cautious, 

 suggesting the record heat may just 

 be an aberration of weather patterns. 



But they agree that if the green- 

 house effect isn't already here, the 

 record heat we're sweltering through 

 now is probably a preview of things to 

 come. 



"The frightening thing is that 1988 is 

 already known to be the hottest year in 

 the recorded history of the earth," says 

 Len Pietrafesa, a Sea Grant researcher 



and physical oceanographer at North 

 Carolina State University. "This is a 

 global phenomenon. You just can't ig- 

 nore that." 



The theory behind the greenhouse 

 effect is simple. 



Since the Industrial Revolution, the 

 use of fossil fuels such as coal and oil, 

 has dramatically increased the amount 

 of carbon dioxide in the atmosphere. 



Add to that other pollutants, such as 

 methane, nitrous oxide and chlorofluor- 

 ocarbons. The result is a collection of 

 gases that blanket the Earth. 



To make matters worse, we've chopped 

 down much of the world's forests. And 

 that just compounds the problem since 

 plants help reduce the amount of car- 

 bon dioxide through photosynthesis. 



The price we must pay for our auto- 

 mobiles, airplanes and smokestacks is 

 life in a more intense greenhouse. 



Under normal conditions, the rays of 

 the sun warm the Earth, and Earth 

 reradiates heat to the atmosphere. But 

 some of the heat is retained in an 

 opaque ceiling of gases around the 

 globe. The ceiling acts as the glass 

 roof of a greenhouse. 



But the additional gases that we've 

 dumped into the atmosphere are cre- 

 ating an even thicker ceiling of gases 

 around us, trapping more heat in and 

 allowing less heat to escape. Thus the 

 greenhouse is getting hotter than it 

 would otherwise. 



The extreme example of the blanket- 

 ing effect of carbon dioxide is Venus. 

 With an atmosphere of 97 percent car- 

 bon dioxide, the planet absorbs 100 

 times the heat Earth absorbs. 



Nobody expects the Earth to be- 

 come another Venus. But according to 

 estimates from the National Academy 

 of Sciences, if the gases continue to 

 build up around the Earth, we can ex- 

 pect a warming of 3 to 9 degrees 

 Fahrenheit by the year 2050. 



In testimony to a congressional com- 

 mittee, James E. Hansen of the 

 National Aeronautics and Space Ad- 

 ministration, said he was 99 percent 

 certain that the current warming trend 

 was caused by the buildup of gases in 

 the atmosphere. Hansen is director of 

 NASA's Institute for Space Studies. 



If the greenhouse effect does take 

 over, we can expect big changes. 



The country's midsection will all but 

 dry up. And the nation's breadbasket 

 will shift north. Canada will become 

 the biggest food producer in the world. 



And the greenhouse effect will hit 

 close to home. Paul Wilms, director of 

 the N.C. Division of Environmental 

 Management, predicts that by the year 

 2030, there will be a doubling of car- 

 bon dioxide levels in the atmosphere. 



If that happens, temperatures in 

 Raleigh would be higher than those of 

 Dallas, Texas, today. Charlotte would be 

 like Jacksonville, Fla. And the weather 

 in the mountain city of Asheville would 

 be more like that of Mexico City, Wilms 



