Much of science consists of a collection of information that appears to be fact at the time.

I don't mean to downplay the many benefits of scientific investigation. But some great discoveries have turned out to be wrong. Error is a normal part of science. Before you bet your farm on a new scientific finding, you might want to wait for what the Army calls "The Big Picture."

"That's why reports of new findings or discoveries, no matter where or how widely they are reported, should be regarded with healthy skepticism," said Lee Ann Fisher Baron, professor of natural sciences at Hillsdale College.

Take the growing consensus among scientists (and alarm among environmentalists) that global warming is a fact. Maybe this ball of mud we call home is getting steadily warmer--maybe it ain't. I have lived long enough to develop healthy skepticism. I recall during the early '70s, there was widespread concern the earth was cooling down and headed for a "Little Ice Age."

A longer history shows climate has never been static; it's cyclical, with periods of warming and cooling. About A.D. 900, sea ice in the North Atlantic melted to where Norse settlers were able to colonize what are today Iceland and Greenland. Then 400 years later the earth went into a cooling cycle, the ice returned and the Greenland colonies perished.

There were no internal combustion engines then, no coal power plants. But the earth went through its heating and cooling rhythms just the same. Now global warming alarmists say human activity is spewing out "greenhouse gases," which trap heat and warm up the earth. A major greenhouse gas is carbon dioxide (CO₂).

Well, my high-school biology class taught me animals and humans breathe air, consume oxygen and exhale CO₂. Plants perform the opposite function, utilizing CO₂ and releasing oxygen to the atmosphere. If CO₂ is increasing in the atmosphere, isn't that good for plants? If greenhouse gases are causing a warming of the earth, is this necessarily bad?

Besides, it has only been about a quarter of a century since global cooling was a big worry. Don't you think we ought to take a longer look at climate cycles before we attempt rash cures that may or may not work--and may not even be needed?

Regulatory agencies seem to be buying into the global warming idea, although President Bush has delayed enforcing stricter CO₂ emission standards on coal plants. But don't be too surprised if the EPA comes up with rules to outlaw people from breathing unless they are standing next to a plant that will absorb the CO₂.