According to the poet John Gay,
In every age and clime we see,
Two of a trade can never agree.
But, pace Gay, this is not always so. Just before Christmas newspaper readers on both sides of the Atlantic saw a remarkable example of complete agreement between two men who are, perhaps, the most influential meteorologists in the world.
The two felt strongly enough about global warming to write jointly to the national newspapers in their respective countries, Britain and the United States. The frank tone of their letter contrasts sharply with the careful and conservative language normally used by the scientists of the establishment when addressing in public this highly political and very emotive issue.
They were prompted to speak, they say, by recent statements by prominent members of the business community, particular ly in the US, asserting that perhaps the current fears of global warming were exaggerated.
The two begin by highlighting the alarming climate trends of recent times: in central England, where the longest set of recorded temperatures exists, 1999 is likely to be the warmest since records began in 1659; in the US, 1999 will be the second warmest year since 1980.
They say that "the rapid warming since 1976 of 0.2 per decade is consistent with the projected rate of warming based on human-induced effects. In fact scientists now say they cannot explain this unusual warmth without including the effects of both human-generated greenhouse gases and aerosols.
"Our new data and understanding," the letter continues, "now point to the critical situation we face: to slow future change we must start taking action soon. At the same time, we must start to learn to live with the likely consequences - more extreme weather, rising sea levels, changing precipitation patterns, ecological and agricultural dislocations, and the increased spread of human disease."
Who, you might wonder, are this gloomy pair who sought to disrupt the complacency of our Christmas celebrations?
Published simultaneously on both sides of the Atlantic, the letter was signed by Peter Ewins, chief executive of Britain's Meteorological Office; it was also signed by Dr James Baker, who, as administrator of the US Oceanic and Atmospheric Administration, fulfils much the same role in the United States.
Ewins and Baker end their letter with an arresting line: "Ignoring climate change will surely be the most costly of all possible choices, for us and for our children." When "two of a trade" agree so strongly, perhaps it is time for the rest of us to take the matter seriously.