The average maximum temperatures [of SE Australia] during the last 35 years were between two and four degrees (F) lower than the average for the previous 35 years. — CSIRO 1953
Once upon a time — before the Great Politicization of Climate Science — CSIRO was able to analyze trends from 1880 to 1910. In 1953 CSIRO scientists were making a case that large parts of Australia had been hotter in the 1880s and around the turn of last century. They are referring specifically to summer maximums, and presumably the increase in rainfall over the same period played a large role in preventing hot days from becoming hotter. Minimum and mean trends may have been quite different, but these older maximum records are surely relevant when news headlines are drafted today about hot summers and heatwaves.
So what happened to the widespread lost hot decades?
I have a lot more to say on the warm and the work of these scientists. For the moment, the full archived news story is entertaining in its own right. Thanks to Chris Gillham for this link and to Jennifer Marohasy. Graphs tomorrow : – )
— Jo
The Argus (Melbourne, Vic) Wednesday 18 March 1953
MELBOURNE’S WEATHER IS CHANGING!
And it’s not being caused by atom bomb explosions. The bomb school of conjecture can be disposed of swiftly, because the energy of a single average storm is equivalent to that of between 10,000 and 100,000 of our atom bombs.
“The change varied in different areas. Bendigo has cooled off 3.6 degrees (2C) over the period; Omeo, 3 degrees (1.7C); Echuca, only 1.6 (0.9C); and Albury 0.8 (0.45C). At Alice Springs the fall has been 2.3 (1.3C), and at Bourke 2.4 (1.3C) But Hay, in New South Wales, has cooled off 3.1 (1.9C) degrees, and Cooma 4.7 (2.6C).”
The change in the climate is sufficiently noticeable, and is considered important enough to have engaged leading weather scientists in extensive re- search.
They are Dr.’C. H. B. Priestley, officer in charge of the meteorological physics section of the Commonwealth Scientific and Industrial Research Organisation, and Mr. E. L. Deacon, a senior officer of the section.
Mr. Deacon found that, in south-eastern Australia in particular, the summer days were gradually getting cooler quite noticeably. The average maximum temperatures during the last 35 years were between two and four degrees [F] lower than the average for the previous 35 years.
The change varied in different areas. Bendigo has cooled off 3.6 degrees over the period; Omeo, 3 degrees; Echuca, only 1.6; and Albury 0.8. At Alice Springs the fall has been 2.3, and at Bourke 2.4. But Hay, in New South Wales, has cooled off 3.1 degrees, and Cooma 4.7. [degrees F]
The places named in the Argus article as having cooled over the 70 years to 1953.
But while the days have got cooler, the nights have got warmer, more or less evening averages out.
The change in rainfall was found to be even more remarkable than that in temperature.
In Melbourne, for Instance, the researchers found that Melbourne’s average summer rainfall for the 1911-1940 period was 16 per cent, higher than the average over the previous 30 years; in Victoria the increase was about 20 per cent.
But what is the cause of this’ And is it likely that the change will continue in the years ahead?
Scientists are cautious about forecasting. All that Mr. Deacon could say about the future was. “There is no evidence that the change is altering.”
So far as causes are concerned, they are still a matter for research. But there are two schools of thought:
The first is that variations, or changes, in the sun condition — sunspots, for example — directly influence weather, but so far there is no clear picture of effects.
The second, toward which Dr. Priestley and Mr. Deacon incline, is that the change is more a result of the make-up of the earth itself; some regions are ‘more delicately “poised” than others; while most of the populated areas are “stable,” and would require substantial changes in the sun to affect their climate, others are “unstable,” and would react to SLIGHT sun changes.
Among these unstable areas is the Antarctic polar ice cap. Australia, while relatively distant, from the polar cap, is particularly open to it; probably Victoria’s changing climate is caused by big changes in the ice cap, the effect of them being brought here by the winds and the ocean currents.
The two theories apply equally to the increased summer rainfalls.
The Northern Hemisphere is experiencing its weather changes, too — they appear a little more dramatic than ours, because they have affected the northern glaciers. (New Zealand glaciers are known to have “retreated,” too.)
Professor Ahlmann. a distinguished glaciologist, ‘writing of Iceland, says that the present, shrinkage of glaciers there is “exposing districts which were cultivated by early medieval farmers, but which were subsequently overridden by ice for 600 years.”
But, say the scientists, research in the Northern Hemisphere has concentrated on latitudes higher than Australia, and it may well be that essentially the same processes are at work in both hemispheres, bringing less severe winters in the higher, and milder summers in the lower, latitudes.
“Both of these effects would result from more vigorous wind systems, of which there is independent evidence,” Dr. Priestley said.
One proof of the “warming” of the far north is in the migration of fishes to waters which were once too cold for them; another is in the appearance of vegetation in zones where once no vegetation lived.
If these changes continue, it is clear that other important changes — economic, social, and physical — will follow. In the north, tracts now fertile may become desert; in the south, deserts may become fertile.
So, when the man in the street says “The seasons are changing,” he’s speaking an actual and important truth – but the sweeping changes, those that affect the earth’s surface greatly, are very slow, and their time scale is measured in thousands of years.
[FOOTNOTE: Melbourne holds the world record for the suddenness of its cool changes. Causes: Presumably, the presence of relatively hot desert, land masses, and relatively cold sea water. The cold water, in its turn, is caused by our “openness” to the Antarctic.
FOOTNOTE 2: It is, therefore, established that Melbourne’s weather is remarkable.]
Source: Trove archives