Ian Plimer The Spectator Australia 17 December 2022
Doug Sprigg, owner of the Arkaroola Wilderness Sanctuary, and I are traversing the continent using isolated station tracks in my 57-year old Volvo Amazon on a rerun of the last sector of the 1968 London-Sydney rally. The aim of my codriver is impressive. He hits every pothole, bump and corrugation. The 82 competitors joyfully emit huge amounts of the plant food carbon dioxide. Maybe we’ll expire upside down in a ball of high-octane fuel flame which will not only help vegetation but will remove a thorn from the side of the Greens?
The rocks of coastal Western Australia are the same as those in eastern India because the Indian subcontinent drifted laterally away from WA. The annual rate of lateral continental drift was far greater than modelled vertical sea level rise. Continental drift changed the shape of the ocean floor thereby changing sea level, something not considered in models. The rocky parts of most of arid WA we traverse have pebbly laterite soils formed during previous tropical times eons before primates appeared. These soils are covered by wind-blown sands deposited during the last glaciation.
While airborne over sand dunes in a white knuckle grip of the passenger seat, I divert my focus to huge sparsely vegetated dunes that were deposited by howling anti-cyclonic winds during the last interglacial when Australia was cold, windy and dry. Europe and North America were then covered by ice. Huge meandering river systems and their flood plains dried to salt lakes. In warmer wetter periods during and after the last interglacial, evaporation from wet soils precipitated pebbles of calcrete (calcium carbonate) in dune sands. This evaporation has naturally sequestered carbon dioxide from the atmosphere. Rolling and wetting calcrete gravel during outback road construction results in slight dissolution and recementing of calcrete into a firm fast less dusty surface. Except when it isn’t and we fishtail under brakes into seemingly bottomless cavernous axle-breaking holes that appear out of nowhere.
Gravels, sand, mud and coals deep in these salt lakes show that it was far warmer and wetter in the distant past. If we stitch Australia back to Antarctica, these meandering water courses now covered with salt in arid Australia join up with glacial valleys in Antarctica.
As we scoot through rural hamlets, I think of country folk who buy retail, sell wholesale, pay freight for both directions and travel long distances for basic medical, education and professional needs.
When fuel and freight prices rise, they cannot pass on costs. They have no control of the weather, political whims, bureaucrats, energy and transport costs, exchange rates and international pricing, supply and demand. They have a good year or so each decade. Farmers with fertile agricultural land struggle to produce food as the increasing and crippling load of nonsensical red and green tape penalises and doesn’t encourage employment-generating food production for the cities.
Many farming families have given up and get paid to sterilise good farming land for growing trees or covering land with toxic solar panels. Our great nation-building outback stations where people risked everything for more than a century have been destocked and overseas owners gain carbon credits by letting the country become overgrown with introduced weeds. Historic homesteads fall apart, fences fall down, fires increase and paddocks are invaded by feral animals.
Further down the track, we bounce over the limestones of the Nullarbor Plain followed by over a thousand kilometres of mallee-covered dune sands. The solid rock limestone contains 44 per cent by weight of the gas carbon dioxide. Limey rocks, life, sedimentary rocks, coal and oil have naturally sequestered carbon dioxide from the atmosphere for thousands of millions of years from some 20 per cent to the current 0.04 per cent. We certainly do have a crisis with carbon dioxide. There is just not enough of it in the air.
My mobile mental calculations show that in the Flinders Ranges we traverse 600,000 cubic kilometres of dolomite, a rock that contains 48 per cent carbon dioxide sequestered immediately after the planet was twice totally covered and uncovered by ice. We speed across sequences where sea level had risen by 1,500 metres leading to two great natural experiments to form multicellular life in warm, shallow nutrient-rich ocean waters. We again cross character-building, denture-chattering dune country. The Flinders Range preserves past climate changes that were the greatest our dynamic planet ever experienced some 650 million years before humans appeared.
After some 5,000 km we cross the Barrier and Great Dividing Ranges and Murray-Darling Basin, my thoughts turn to Jacinta Ardern. Long travel induces weird fantasies. About 100 million years ago, Australia and New Zealand moved northwards from Antarctica. NZ also drifted eastwards giving them well-deserved earthquakes and volcanoes and they gave us the fertile basalt and alluvial soils of eastern Australia. As a result of the Tasman Sea opening, western NZ and the Great Dividing Range started to rise, decompression produced volcanoes such as Norfolk Island, Balls Pyramid, Lord Howe Island and valley-filling basalt lava flows all along eastern Australia.
The Nepean River flood plain started to form at least 45 million years ago and there has been flooding ever since due to NZ pushing and pulling us. The Blue Mountains rose bit by bit and there was slight doming producing the Hornsby and Woronora Plateaux. The course of the Nepean River changed many times, boulders in gravels came from near Goulburn and some from Emu Plains were shaped by aboriginals for axe heads.
Eastern Australia continued to rise and be rattled by sporadic earth tremors, as it is today. Gravels and sands were reworked many times in flooding events, the whole Nepean River was dammed producing an extensive clay horizon and, after breaching of the dam, the Nepean flood plain continued to enjoy millions of years of flooding and draping by fertile alluvial sediments. Long-term repeated inundation of the flood plain is not unprecedented and is certainly not helped by housing developments which change the proportion of runoff to soakage, change river dynamics and expose capital to flood damage loss.
If humans are to be blamed for the Nepean River flooding, then blame Jacinta. NZ did not join the Federation as a separate state in 1901 because they considered themselves from superior stock. Jacinta disproves this and reckons she can change the global climate. Unless she can change the weather for us across the ditch, we should send her the damage bill for flooding west of Sydney due to NZ pushing and pulling eastern Australia to produce the flood-prone Cumberland Basin.