The following passage is by former Met Office supremo Hubert Lamb. Published at the height of the global warming scare – ironically just before the onset of ‘The pause [which] is a grand ‘whodunnit’ at the edge of our scientific understanding – Lamb made the polar opposite view of current Met Office Chief Scientist, Julia Slingo. Remember this when we are told the debate is over and you find your voice is censored.
In 1896 the Swedish scientist, Sv. Arrhenius, professor of physics first at Uppsala and later in Stockholm, published his suggestion that increasing the carbon dioxide in the atmosphere, as was already happening relentlessly, should be expected to warm world climates because of its absorption—i.e capture—of long-wave radiation that continually goes out from the Earth and so create a sort of ‘greenhouse effect’. And in 1938 in England G S Callendar seemed to show in a paper in the Royal Meteorological Society’s journal that the observed warming of surface temperatures over the Earth by about half a degree Celsius from around 1890 to the 1930s should be about right to be attributable to the radiation trapped in the atmosphere in this way. But there are some difficult points. Water vapour, which is abundant in the atmosphere except over the coldest regions of the Earth and in the stratosphere, also absorbs radiation and on almost al the same wave-lengths that the carbon dioxide absorbs.
Difficulties, too, beset attempts to show how variations in the amounts of carbon dioxide in the atmosphere in the past fit the theory that warm periods in world climate can be attributed to a greater CO2 content and cold periods to a lower CO2 amount. The CO2 content at various past times is presumably indicated by the gas trapped in bubbles in ice-sheets and glaciers. This does show less CO2 in glacial times, and during warmer interglacial periods the CO2 amount were greater. But, since carbon dioxide is more soluble in water—in the oceans for example—when temperatures are lower, the smaller amounts of CO2 in the bubbles in the ice sheets in ice age times could be just a result of the colder climates then prevailing. And, even within our own times, the suggestion that the increasing carbon dioxide in the atmosphere should be presumed to be the cause of the warming does not fit at all well with the sequence of observed values.
The great period of warming, at least in the northern hemisphere, was during the first 40 years of the 20th century (especially the first and fourth decades), but in the 1950s and 1960s when the CO2 was increasing more rapidly than ever before the prevailing temperatures were falling. Callendar himself was worried by this discrepancy and contacted both me and Professor Gordon Manley about it. There seem, in fact, to have been a number of shorter runs of sometimes up to 50 years with either rising or falling temperatures often setting in suddenly, and with no clear correspondence to changes in the atmospheric CO2 content.We also see that account must be taken of psychological reactions—even in the influential research community—to the variations towards greater or less warmth as and when they occur.
In the 1880s and 1890s, as a recent American meteorological investigator was the first to be able to show, world temperatures were lower than they had been since around 1850. That was just when Arrhenius came out with his suggestion that the man-made increase of carbon dioxide should be warming the Earth. And at that time the suggestion made little impact. When Callendar promoted the same idea 40 years later, however, it was in a warmer world, though very soon the bitter war winters came and implanted themselves in folk’s memories. And when G N Plass again put forward the CO2warming theory in papers published in 1954 and 1956, world climate was once more entering a colder phase, particularly in the northern hemisphere. Interest in the theory soon waned. It only revived after a run of up to 8 mild winters in a row affected much of Europe and parts of North America in the 1970s and 1980s. There then came a tremendous preponderance of publications on global warming, dominating the research literature, although over-all temperature averages in some regions, particularly in the Arctic, were still moving downward.
So, in spite of the sharp turn towards warming after 1987-8, and the undeniably very warm years 1989-91 and 1995, one must feel uneasy about the confidence with which global warming has been publicised as the verdict of science in official pronouncements from many quarters. The erratic course of the changes experienced through the 20thcentury surely suggests that there are processes at work which are still not adequately understood and possibly even some influences that have not yet been identified.[1997, p217-19]