Authors: Chris Turney
It is important to realise that within the westerly winds that dominate the mid-to-high latitudes of the south, the air can also spin, creating areas of spiralling low pressure that migrate around the ocean. It is these lows in what is known as the circumpolar troughâoften spanning several hundred kilometresâthat can swing in towards the Antarctic coastline. In an El Niño year, the lows tend to sit for longer over the eastern Ross Sea during autumn and winter.
Because air flows around southern hemisphere lows in a clockwise direction, these strategically placed pressure systems encourage katabatic winds to whip off the plateau and down to the Ross Ice Shelf, where they are funnelled west, and then north by the mountains of Victoria Land. This created unusually cold conditions in the western half of the Great Ice Barrier when Scott and his men were attempting to get back to Cape Evans.
In March 1912 the British team found the summer was ending far sooner than expected. During their attempt to get back to base the struggling party was hit by a succession of blizzards that pushed temperatures more than 10°C lower than normal. This is just what we would expect during an El Niño. Simpson wrote, âThere can be no doubt that the weather played a predominating part in the disaster, andâ¦was the immediate cause of the final catastrophe,' and concluded: âthe Barrier could be traversed many times without again encountering such low temperatures so early in the year.' Recent scholarly investigation, most notably by Susan Solomon in her fascinating book
The Coldest March
, has shown that 1912 was exceptionally cold, even in the context of modern weather data.
The work done on Mawson's expedition supported the British interpretation. Weaving in the Australasian expedition's results, the New Zealand meteorologist Edward Kidson was able
to build on Simpson's work and produce daily weather maps that spanned the Antarctic to the tropics. The new continent was not nearly as meteorologically isolated as had been thought. Kidson showed that the changes in atmospheric pressure recorded by the different expedition barometers of 1912 were tracking the seemingly endless procession of lows from west to east.
During 1913 Frank Wild claimed in
The Times
that âfrom March 21 for a period of nine days we were kept in camp by the same blizzard which proved fatal to Scott and his gallant companions'. At one level he was right. Kidson's work indicated that the successive low pressure systems were all linked. As Wild and his men were pinned down by a blizzard, the same low-pressure system was sweeping inexorably east towards the Ross Sea, keeping the British team trapped. Antarctica's weather danced to the changes offshore. Scott really was in the wrong place at the wrong time.
On a cold evening in January 1914 a long procession of people converged on the plush red-brick premises of the Royal Geographical Society, in central London's Kensington Gore. The society had just moved into its new home and was leaving behind the controversy that had inadvertently kick-started the explosion of work in the south. Female fellows were now openly welcomed, and the RGS was tackling the twentieth century with confidence. It was a fresh start for all.
This particular January night was unusually busy. Held on the eve of World War I, the meeting was not about the geopolitics of the region. Instead, lodging their heavy outdoor clothing at the cloakroom, the audience members had come to hear a speech by one of the scientific heavyweights of the era, âProf' Edgeworth David.
David was here to show how the research of 1912 had spectacularly advanced the world's knowledge of Antarctica. It seemed fitting that he provide this overview. Although he had not been south for five years, David had maintained contact with many of the expeditions, helping them to interpret their results and weaving these into his own findings from Shackleton's
Nimrod
expedition.
Over the next hour David gave a dizzying survey of what had been discovered in the new continent and the research questions that remained. Where things were hazy he intuitively suggested hypotheses, many of which would be confirmed decades later. There was no one better informed.
In his posthumously published book,
The Lands of Silence
, Markham declared that the âgreat object of Antarctic exploration is to discover the outline of the Antarctic continent, and to study the physiography so far as the great ice-cap will admit of such researches'. The year 1912 was a watershed in this regard. The exploratory work had gleaned an understanding of what lay south.
Not only were new coastlines found, David remarked: others that had confounded explorers for years were finally dismissed. The Australasian expedition, with Davis captaining the
Aurora
, had proved that the Company Islands were a mirage, while in the Weddell Sea, Filchner had escaped the bullets of the
Deutschland
crew to show that Morrell Land was most likely a figment of an eccentric American sealer's imagination.
Mawson likened Antarctic exploration to discovering missing parts of a huge and complicated jigsaw. Thanks to the exploits of five teams in an amazing short burst, several large pieces of the puzzle were unearthed and the picture started to make sense.
Often sustained by sheer willpower, the teams had worked against the odds to show the great white continent was not just a vast wilderness. Some 8500 kilometres of the coast had been
mapped on oceanographic cruises. As a result of these efforts the Antarctic coastline looked to be 22,500 kilometres longâan estimate not far off the eighteen thousand kilometres that today we know it to be. And where sledging parties had gone inland, vast tracts of previously unknown ground had been discovered. Mawson's expedition alone explored 3200 kilometres, while Amundsen covered 2800 and Scott a further 460.
One huge uncertainty before 1912 had been how the continent's mountain chains linked upâif they linked up at all. From Amundsen's descriptions and photographs, the Beacon Sandstone first described in Victoria Land seemed to extend to the Axel Heiberg Glacier, which the Norwegian had climbed to reach the plateau. Unfortunately, at the other end of the continent, Filchner had fallen short of a suite of rock samples from Prinz Luitpold Land. David was disappointed, because this would have conclusively shown whether the new coastline joined the mountains Amundsen had seen carrying over the horizon.
There was a strong reason for supposing they did. The wholly different geology of the Andes tended to support Amundsen's observations that this mountain range continued towards Prinz Luitpold Land, a staggering distance of 3500 kilometres, making it one of the longest mountain ranges in the world.
If the mountains of Victoria Land did indeed cut across the continent, the question remained whether the barriers of the Ross and Weddell seas linked up, cutting Antarctica in two. The Japanese expedition looked south from King Edward VII Land and saw high ground that implied the presence of land; Amundsen suggested there might also be mountains to the northeast of his point of ascent, which he called Carmen Land.
If these were realâthough because of the known refraction of the air in this part of the world, they might have been hundreds of kilometres awayâthere could not be a wide strait, David argued. Filchner's Luitpold Land, at the southernmost
part of the Weddell Sea, lent support to the idea. At best there was a narrow strait. Decades later, David's supposition was proved correct.
After the expeditions of 1912 there was a backlash against the bewildering array of names being given to different parts of Antarctica. People were getting tired of the landscape being named after monarchs and rich benefactors. Today naming is strictly controlled and many of the locations in Antarctica have been retitled. Although individual mountains have largely kept the titles bequeathed to them, the chain that cuts a swathe across the continent now goes by the name of the Transantarctic Mountains, while the Antarctic Andes are best known as the Antarctic Peninsula.
With this rationalisation, there was also a recognition that the word âbarrier' did not do justice to the extraordinary features found in the Ross and Weddell seas. During 1912 the Australasian team discovered a similar floating formation on the east Antarctic coastline. This find was given a more accurate term, and named after the Anglo-Irishman who had supported the Australasian effort: the Shackleton Ice Shelf. It would be some years before the Great Ice Barrier became known as the Ross Ice Shelf. But the work undertaken by the British and Norwegian teams did show that this enormous feature was essentially flat and rose only very slightly towards the Transantarctic Mountains.
Shirase's team had found the only significant amounts of rock debris in the barrier ice near the coast of King Edward VII Land and close to numerous outlet glaciers, giving a strong clue about its formation. David astutely realised that the ice shelf must be shaped by a combination of factors: ice flowing in from
surrounding glaciers and snow falling from above, melting at the base and calving into the Ross Sea.
The timescale involved was vast. The British calculated the barrier's movement was somewhere in the order of 460 metres each year, not far off today's estimate of a metre a day. And, thanks to the mapping efforts of 1912, the Ross Ice Shelf was shown to be equivalent in size to France, allowing David to calculate that it took some twelve hundred years for âice at the apexâ¦to travel to the sea cliff'.
But it was by crossing the crevasse-torn ice shelf that the most significant discoveries about this ancient landscape were made. Shackleton found a succession of different rock types exposed in the mountainsides at the top of the Beardmore Glacier, at a spot known as Buckley Island. Thanks to detailed work by Scott and his team, it was realised that Mawson had found the same sequence of rocks some 2250 kilometres away. Although finding an identical geological pattern in two different locations, albeit over a huge distance, was not in itself thrilling, one part of the sequence excited considerable comment: coal.
In 1912 it was well known that the existence of coal spoke of forested swamps in the past. Based on the plant remains the Antarctic coal contained it was evident there were parallels to those found in other parts of the world during a geological period of luxuriant plant growth known as the Permian, more than 250 million years ago. This geological link helped David, an expert on Australian coal, to decipher the geological history of Antarctica.
The mere presence of coal posed a tricky question: how did vestiges of ancient forests come to be found at the Beardmore Glacier? As David remarked, âWe are thus confronted with the extraordinary problem of trees, probably coniferous, flourishing with 5° of the South Pole itself in a zone which is now, in
winter-time, more or less in complete darkness for five months in the year.'
Prophetically, David asked: âCould this coal-flora have flourished, even under warmer conditions, with the Beardmore glacier situated in its present relation to the South Pole, so that the flora would have been in darkness for five months of the year? If not, has the Pole shifted, or has Buckley Island shifted in regard to its present distance from the Pole?'