Science journalist Gabrielle Walker’s book Antarctica: An Intimate Portrait of a Mysterious Continent (Bloomsbury, 2012) tells an absorbing story of the wide variety of scientific work undertaken in Antarctica and the support services that maintain it. It also attempts to capture the human fascination of the continent, not least for the author herself in her five sojourns there. She provides close-up observations of some of the specialist teams working on an array of investigations: penguins, seals, under-ice sea creatures, meteorites, astronomy, paleoclimatology, the dynamics of ice movement and loss, and more. Stories of the early explorers find a place, and the psychology which motivates people to undertake sometimes long scientific enterprises in such a demanding environment. Her book is striking and highly readable, often gripping.
It’s the climate change aspects of the book that I want to highlight here. Walker, who has a strong academic science background, specialises in energy and climate change. She co-authored a book on climate change with Sir David King a few years ago. I reviewed it at the time. Her knowledgeable familiarity with the subject is often in evidence in Antarctica.
Her visit to the European drilling site at Dome C she describes as a pilgrimage. She had read about the ice cores, spoken with dozens of scientists about the results of their examinations in the freezers back in Europe, and watched some of those examinations taking place. But she wanted to be present at the drilling itself. Her account of what she observed is eye-opening. The technical complexity of the operation kilometres down into ice 800,000 years old is set out in close narrative detail, with all its accompanying drama. The expensive loss of a drill 800 metres down meant starting over again.
Walker provides a readily understandable account for the general reader of how the ice cores record the succession of ice ages and interglacials over the past 800,000 years. She explains how the water in the cores reveals past temperatures through the ratio of light and heavy molecules in the snow of the time; the air trapped reveals the composition of the atmosphere at the same time. Higher temperatures went along with higher carbon dioxide and methane, lower temperatures corresponded with lower carbon dioxide and methane.
So much for the natural cycles of the ice ages, triggered by earth’s orbital changes and amplified by greenhouse gas levels. But in all that time, Walker explains, carbon dioxide has never been within striking distance of the amount we have today. Through the entire record, the highest value was about 290 parts for every million parts of air. It is now 400 and rising. Her conclusion: “The deepest voids of Dome C hold a warning that we would do very well to heed.”
Climate change is again to the fore when Walker moves her focus from East to West Antarctica, staring with the Peninsula. Here she inserts an admirably lucid explanation of the gradual process by which carbon was sucked out of the atmosphere of hothouse Earth by the burial of trees in swamps and of sea creatures in the floors of shallow seas, enabling the world to start a cooling trajectory and Antarctic to begin its transformation to the frozen continent.
But now, as we mine and extract the fossilised fuels and pour their carbon back into the air, the planet’s temperature has already risen by nearly 1 degree over the past century and the effects are being felt here on the Peninsula more strongly than anywhere else. This part of the continent is warming at an extraordinary pace – three times the global average.
“It is one of the planet’s hot spots, melting visibly under the eyes of scientists and their instruments. Its shelves of ice are shattering. It is shedding icebergs like armadas. Even the animals are feeling the heat.”
Krill are among those animals. These sea creatures so basic to the marine food chain are reported as suffering significant decline, with flow-on deleterious effects for the seals whales and penguins that rely on krill for their food.
The Peninsula is losing ice. In itself this is not enough to seriously affect sea level rise, but it is suggestive for the vulnerability of other much larger areas of ice in West Antarctica. In the year or two since Walker’s book was published there have been new studies confirming that vulnerability, but when Walker was writing there was already evidence that the supposed stability of the great ice sheet was in doubt. She explains in detail the work of scientists who discovered that the hinge lines where the West Antarctic glaciers join their floating ice shelves were moving inland at a rapid rate and that the glaciers themselves were observably thinning.
Walker then tells of the suspicions that warm water in the ocean was responsible and of the discovery that indeed in the Amundsen Sea warmer deep water which was normally kept away from the Antarctic ice by a gigantic underwater shelf was here able to creep up through channels and lap against the ice, gouging it from below.
The remaining question was how far this process could extend inland. That depends on the land beneath the glaciers. In the case of the Thwaites glacier there is no such obstacle and, because it is not contained in a trough, melt could spill into other ice streams.
The prospect for sea level rise is dire. When added to the sea level rise expected from melting ice in Greenland it would be, comments Walker, “enough to cause death and destruction, particularly among the many millions living on low-lying deltas in the developing world.”
Walker acknowledges that this West Antarctica research is all very new and fresh and there remains a lot to learn. But since she wrote there has only been further scientific confirmation of how exposed the Amundsen Sea glaciers are to the predation of a warming ocean.
Walker’s book, in its patient narrative of scientific field study in the Antarctic, leaves the lay reader with an understanding both of the rigour of the science and of the way in which teams of scientists gradually contribute to the impressive edifice of knowledge that climate science has become. Whether the political world is capable of responding to that knowledge is sadly still moot, but we can’t say we haven’t been clearly told what it portends.