A Roman ruffian by the name of Publius Clodius was once alleged to have had designs on Julius Caesar's second spouse, Pompeia. Pompeia, it seems, was completely innocent throughout the whole affair; nonetheless, when the matter came to light, Caesar divorced her on the spot - on the grounds, he said, that "Caesar's wife must be above suspicion".
When it comes to theories about climate change, a discipline with many vested interests, meteorologists - like Caesar - must be careful of the company they keep. The Intergovernmental Panel on Climate Change is an ideal Caesar's wife in this regard. It is a standing committee of international experts which, to mix a metaphor or two, has been sitting for a about dozen years. It has no political or economic axe to grind, and operates under the joint auspices of the World Meteorological Organisation and the United Nations Environment Programme.
Its purpose is to be an informed institutional framework through which a consensus, an authoritative "best guess", can be arrived at on the thorny questions of global warming and the enhanced greenhouse effect.
In 1990, the IPCC produced its first report and was very cautious. The experts confirmed that the average temperature of our planet had increased by half a degree in the previous century, but stressed that this increase was well within the bounds of "natural climatic variability". In other words, it might have happened anyway.
Since then, the IPCC has produced several reports, and the last, three years ago, was recognised as a decisive shift. It said: "The balance of evidence suggests a discernible human influence on global climate." The next report is due in 2001, and since even those above suspicion find it hard to keep a secret, there are confident rumours as to what it will contain.
It is likely to observe that since 1976 the world has been warming at a rate equivalent to 2 Celsius per century. By deducing conditions in the past from tree rings and other evidence, the experts, apparently, conclude that this rate is "unprecedented" in the last 1000 years and can only be plausibly explained by taking account of human influence.
Other factors that affect the global climate, like changes in the amount of energy coming from the sun or volcanic dust thrown into the atmosphere from time-to-time, would have caused the average global temperature to fall, rather than rise, during the past two decades.
A finger, belonging to a body whose expertise and bona fides are above suspicion, points unequivocally at us, the human race, as the culprits of the phenomenon of global warming.