It's indisputable that the accumulation of carbon dioxide (CO2) in the atmosphere has increased in the past two centuries. Systematic measurements begun in 1957 have recorded this trend, and analysis of air bubbles in glacial ice in Antarctica and Greenland confirm that this rise began around 1800 with the onset of the industrial revolution.

But a debate is still taking place among scientists on what level of concentration, if any, of "greenhouse gases" can spark a warming trend. They also disagree as to whether the current accumulation is sufficient to do so, and whether it has already begun. A recent declaration issued in Leipzig by some 100 scientists questioning whether global warming has begun is testimony to the continuing debate.

The principal evidence that warming has begun is a rise in the average worldwide land-based temperature in the past 100 years by one degree. But it has yet to be proved that this is the direct result of CO2 accumulation, and not the natural recovery from a short cooling period of about 400 years. The Earth has been in an overall warm-up since the last ice age reached its peak about 15,000 years ago -a period punctuated by cooler periods of hundreds of years. Temperature records for 100 years are based on too short a time period to definitely say that a new direction has begun. I'm not persuaded that a heat wave one summer in India and the U.S. Midwest proves anything.

Some scientists predict that based on what we know of previous ice age cycles (and there is no accepted consensus for the cause of ice ages), we're soon headed toward another era of cooling. If, so, what effect would this have on a potential "greenhouse effect?" The Earth's climate is affected by a wider range of factors than glassed-in greenhouses, including the movement of ocean currents that are only beginning to be understood.

Right now we have conflicting computer models of what might happen if CO2 buildup continues. That accelerated global warming might happen should be sufficient proof that working people need to overturn capitalist rule and replace it with a government of our own that will protect the environment from pollution and safeguard the Earth's ecosystem.

- DOUG JENNESS  
 
 
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