Hidden variables part of global warming issue

It is not about consensus. Consensus is not science.

Debate itself is about arguing a point while backing it with evidence, which might be fragmented and incomplete, and which makes the debate rather beguiling.

This is what I came away with after seeing Al Gore's An Inconvenient Truth. Something was missing. But what? A hidden variable?

My work as an industrial analyst took on environmental issues in ground water, soils and bay muds, where corrective measures had to be taken for discovered pollutants. Hence, I was sensitised to the causes and effects of such environmental problems.

But, frequently there were deeper issues that didn't readily appear, which can be hidden variables. For example, there is mercury in South San Francisco Bay mud sediments that came from cinnabar (mercuric sulphide) deposits in New Almaden, which were washed down over geological time periods, and not because of the hand of man.

In another case, Lake Erie had algae blooms early in the last century, which occurred again in later years when it was attributed to phosphate-based detergents and fertilisers that had not existed in appreciable quantities in the early 20th century.

When it was found that carbon dioxide was the underlying culprit because of organic decomposition from sewage pollution, it came too late to reverse the ban on phosphates. The environmental chemists hadn't dug deep enough to ferret out the underlying cause. And now this issue is closed to debate.

The prohibition on halogenated hydrocarbons in 1972 by the EPA has led to the dramatic increase of otherwise treatable disease vectors, malaria-carrying mosquitoes, resulting in the deaths of millions in developing countries.

Despite scientific evidence for the safe use of DDT, such evidence was swept aside. Hidden variables obviously weren't convenient. One might be moved to think that the capacity for genocide is not limited to acknowledged historical monsters. This is another issue closed to debate.

There is enough scientific evidence to settle the question of global warming without prolonged debate. Moreover, there are literally hundreds of so-called greenhouse gases acting and reacting in our atmosphere, where water vapour is far and away the most effective and prevalent.

However, carbon dioxide has become the principal suspect and scapegoat for global warming ills.

After viewing Al Gore's documentary, which skims the surface rather niftily, one is left with the question as to what might be a deeper issue.

What might be the hidden variables? Has it occurred to anyone that historical episodes of global warming with elevated levels of carbon dioxide show that such past increases in a greenhouse gas is really an indicator and not a cause?

Such indicators, as used in chemical analysis, tell us that something has happened. But, unless you know what the indicator is for, expectations and conclusions can be misleading.

If the current increase of carbon dioxide in the atmosphere is a hidden variable in global warming - an indicator of a deeper underlying cause - then simplistic answers by limiting our exhaust emissions to treat the effect may not be sufficient to get to the real cause.

This is not an issue that can be settled by debate, but by scientific evidence as to the root cause, which I suspect may be more unalterable than anticipated.