Summer weather in New Zealand often continues into autumn. Stretches of fine, mild weather frequently occur in May, despite the shortening day length. This happens because New Zealand is surrounded by ocean. It takes a lot of energy to heat water, and a long time for water to cool down. Consequently, the sea surface reaches its maximum temperature some five or six weeks after the sunlight is most intense, around 21 December. The air blowing over the ocean is heated by the warm surface water and carries the warmth over the land.
Equally, in winter, the coldest sea-surface temperatures occur five or six weeks after the shortest day and so our coldest weather usually occurs in late July or early August.
Over Antarctica’s Ross Ice Shelf, however, the warming influence of the ocean is not often seen, as the prevailing wind blows down off the high plateau. Records kept by Robert Falcon Scott’s Antarctic expedition in 1902 showed a sharp rise in temperature when the sun returned in spring and a rapid fall in temperature as the sun disappeared in autumn. Once the sun was gone in winter, the temperature showed only a small decrease.
Automatic weather stations have now been in place in parts of Antarctica for several decades, providing data studied by atmospheric chemist Susan Solomon of the United States National Atmospheric and Oceanic Administration.
In her fascinating book, The Coldest March: Scott’s Fatal Antarctic Expedition, she compares the temperatures over the Ross Ice Shelf during a recent 15-year period with that experienced by Captain Scott in the last weeks of his fatal journey. Her analysis shows that Scott was extremely unlucky. March 1912 was colder than any of the other Marches, with only one March of the 15 anywhere close. Climate change is not to blame, as that has been shown to have had only a small effect in this area so far.
Crucially, the extreme cold was almost continuous. It affected Scott’s progress in three ways. The snow was so cold the sleds would not slide easily. This cold occurs in conjunction with only light winds, so although the sleds were rigged with small sails to help them along, when they did attempt to travel their progress was only a couple of miles a day instead of the desired 15. Finally, the cold made the frostbite severe, crippling first Captain Lawrence Oates, then Scott, with fatal consequences.
In The Coldest March, Solomon seeks to rehabilitate Scott’s reputation in the face of fierce criticism of his leadership, but she is only partially successful. In The Last Place on Earth, Roland Huntford gives a detailed account of the contrasting approaches of Scott and the Norwegian Roald Amundsen, who became the first to reach the South Pole.
Scott turned to polar exploration around the age of 30, when his naval career seemed stalled, whereas Amundsen grew up wanting to emulate the famous Norwegian explorer Fridtjof Nansen, who made the first crossing of the Greenland Ice Sheet. Nansen’s success was largely due to his use of skis, which had been part of Scandinavian culture for thousands of years. As a child, Amundsen learned to ski on the road outside his home with barrel staves tied to his boots. Scott did not try skis until he reached Antarctica, and never mastered them.
To learn about Arctic seafaring, Amundsen spent a season on a sealing expedition. He then completed the first successful navigation of the Northwest Passage, sailing from the Atlantic to the Pacific. Wintering in Canada, he befriended the Inuit, learned their language and adopted their caribou-skin clothing. The Inuit taught Amundsen how to make igloos and how to run dog-sleds. When the temperature dropped below minus 30°C, Amundsen’s sled stuck in the snow and would not glide until the Inuit showed him how to coat the runners in a thin layer of flexible ice.
As an officer in the Royal Navy during the Victorian era, Scott lacked the inclination to study with natives such as the Inuit. In particular, he never appreciated the value of dog-sledding for polar travel. Although he took some dogs to Antarctica, he tried to rely on ponies for transport, without much success. The ponies’ hooves broke through the snow crust and they sank to their bellies, whereas the dogs could run across the surface. Also, dogs sweat through their tongues while their skin remains dry. At the end of a day’s travel in Antarctica, the ponies’ sweat froze into solid sheets of ice on their backs and they had to be rubbed down and covered in blankets, and a snow-block wall erected as a wind-break. The dogs just burrowed into the snow to rest.
Once the ponies died, Scott was obliged to man-haul his sleds to the South Pole. Regarded as more “noble” by Scott’s mentor, Sir Clements Markham of the Royal Geographical Society, man-hauling was far more demanding physically than dog-sledding, requiring more calories and drinking water, of which there was not enough. Using dog-sleds, Amundsen was able to travel three times faster than Scott. Dogs could also travel when it was too cold for ponies, so Amundsen started for the pole 10 days before Scott.
Much of Amundsen’s equipment was better than Scott’s. His sleeping bags were covered by a third light canvas bag. When he and his men slept, water from their breath condensed onto the outer bag and then froze. When they got up, this ice was easily shaken off. Scott’s sleeping bags gradually became heavier with frozen condensation. They became hard to wriggle into and had to be unfrozen little by little by body heat—a slow process that could take an hour.
Despite his mistakes, Scott very nearly made it back. Solomon has shown that in anything like normal weather, he would have reached the last depot in time to rendezvous with the dog-sleds sent out to wait for him. But his margin for error was too fine. In 1912, winter came to the Ross Ice Shelf in March.