`Sweet Helen, make me immortal with a kiss!" pleads Marlowe's Doctor Faustus.
He sees this as a possible escape from his dilemma, earthly immortality being an eventuality unforeseen in any clause of his inconvenient contract with the devil. His optimism was based on the enviable power allegedly possessed by Helen of Troy, who had, as he says:
. . . a face that launched a thousand ships,
And burnt the topless towers of Ilium.
But climatologists have almost done as well: they have launched 1,000 buoys. They also collect information from 7,000 ships and from an array of several thousand weather stations, great and small, situated on the land which covers the remainder of our planet.
It takes them a while to sift through all the data from these various sources but, sooner or later, every year they make an ex-cathedra pronouncement on the year before. Their verdict on 1998 has come to hand.
Last year was very warm. It was, in fact, the warmest year on record: averaged over the entire planet, the global temperature near the surface of the Earth was nearly 0.6C warmer than the average for the last 30 years. It was significantly warmer than 1997, which itself was 0.4C higher than the norm.
These finding are not all that surprising and merely confirm the early estimates of several months ago. However, they show a continuing pattern which some find very ominous.
A graph of the average global temperature for the past 150 years shows hardly any noticeable trend until the end of the 19th century. Then the temperature climbed by O.5C between 1900 and 1940, before settling down again with little change until the middle 1970s.
Since then, the average global temperatures has risen sharply and now the total rise since 1860 is almost 1C
Ireland has broadly echoed this upward global trend. For 1998, the mean temperature was nearly 1C higher than normal, continuing an uninterrupted succession of warm years since 1994.
Much of the anomaly in Ireland was accounted for, not by higher daytime temperature (indeed, our summer was unusually dull and wet), but by the marked mildness of the winter nights.
This, of course, is the pattern in the troposphere, the part of the atmosphere which is nearest to the ground. Higher up, in the stratosphere, the opposite applies; the upper reaches of the atmosphere are getting colder, a phenomenon which is entirely consistent with "greenhouse warming". This is where heat is trapped near the surface of the Earth and cannot percolate upwards to warm the stratospheric regions high above.