Ice, Mice and Men

Geoff Simmons and Gareth Morgan, with help from John McCrystal, have produced a book which one hopes will be read by many New Zealanders.  Ice, Mice and Men: The Issues Facing our Far South not only carries illuminating scientific information about the islands and seas to our south and the Antarctic continent beyond them, but it communicates it in a relaxed and engaging style which should ensure a wide general readership. The more people understand what is happening in this vital region the better, and it’s easy to see this book adding to their number.

The opening section explains why the region is important, breaking it into three zones: first, the subantarctic islands, “liferafts” of the Southern Ocean; second, the Southern Ocean itself, home to the Antarctic Circumpolar Current (ACC) and “the engine room of the global ocean and the world’s climate”; third, Antarctica, including the sea ice that surrounds it which helps drive the marine food chain and affects the transport of nutrients essential for marine life around the world. The section provides a detailed account of the function of the three zones not just in relation to each other but in crucial relation to the globe as a whole.

The treatment of the ACC, for example, explains how the mixing of its waters due to high winds carries warmer surface waters into the depths and presents colder water to the warming effect of the sun, helping to store heat from the atmosphere. It also helps store carbon as it increases the amount of water that has contact with the air, and cold water at that which can absorb more carbon dioxide.  However this service means that the Southern Ocean is acidifying more rapidly than for millions of years.  The role of the ACC in feeding nutrients into all the major oceans is another vital function described by the book, one in which it is aided by the extraordinary ecosystems of the sea ice and floating ice shelves of Antarctica.

The second section of the book deals with the question of the race for resources. It has resulted in much past damage to the subantarctic islands’ wildlife, but on a wider scale it is fortunately so far comparatively muted. However the authors adduce plenty of evidence that realpolitik considerations lurk behind the Antarctic Treaty System and urge the likely need ultimately to strike a balance between complete protection of the area and managing the worst aspects of commercial exploitation by agreeing environmental standards and setting aside some areas as complete reserves.

In reviewing the book for Hot Topic my main interest was its third section which deals with climate change issues in the region. Three years ago I reviewed Gareth Morgan’s and John McCrystal’s earlier book on climate change Poles Apart, which posited a shouting match between alarmists and sceptics and proposed to adjudicate the matter.  There was, of course, no shouting match and there was nothing that required adjudication. The science was as clear in its basics then as it is now, and the authors finally came down solidly on the side of the science. However they still allowed some accusations of a conspiracy on the part of the IPCC to send an overstated message to the public, described Michael Mann’s hockey stick thesis as a grievous overstatement and in policy matters advised against using a sledgehammer to crack a nut.

I’m happy to report that the climate change section of this book is a well-assembled and unequivocal statement of the current scientific understanding, often expressing insights which readers will find helpful. Denial gets short shrift in the initial overview: “Just because a temperature rise historically precedes an increase in CO2 levels doesn’t mean it necessarily does. That is the natural order, after all, and the present warming is not natural.”

Focusing on the southern region the book points to evidence that the Southern Ocean has become warmer, fresher and slightly more acidic, and the patterns of circulation have changed. Wind speeds have increased markedly in recent decades and are shifting south. The impact of this on the ACC is as yet uncertain: whether it will make it stronger or more turbulent, whether the current itself will move further south, and how all that will impact on the role of the ACC in the planet’s ocean mixing.

Acidification alone is alarming enough. We appear headed for a bigger change in acidity than anything seen in the last 20 million years. This means serious stress for anything in the ocean which needs a shell. The shells of modern plankton called foraminifers are becoming lighter than those of their recent ancestors – and this has happened in direct proportion to the increase in acidity. They form a substantial part of the marine food chain. The warning signs of acidification are ominous, and lead the authors to remark plainly: “Along with climate change this is one hell of a risky experiment we humans are embarking on with our oceans.”

The effects of warming on the continent of Antarctica may be less apparent than what is happening in the Arctic polar region, but the book warns that this may in part be due to the now-diminishing ozone hole which has likely helped keep its locality cooler, ozone being a greenhouse gas. Yet warming impacts can be quick and dramatic as we can see in the Antarctic Peninsula and the Amundsen-Bellingshausen Sea. The most severe threats to the Antarctic ice are likely to come from the ocean and the authors acknowledge the difficulties in predicting how this may play out and what it is likely to mean for global sea level rise and for the thriving ecosystems supported by Antarctic sea ice. However geological evidence and sediment cores reveal that in the early Pliocene, with CO2 levels similar to today, temperatures eventually rose enough to melt the West Antarctic Ice Sheet, probably adding some 3.5 metres to a global sea level which was probably 10-30 metres above today including contributions from Greenland, Arctic Islands and other land-based ice.

The final section of the book looks at the conservation imperatives arising out of the damage caused by the race for resources and climate change. The threats are clearly described and useful suggestions are offered for their amelioration under the headings of basic science, fisheries management, marine protection and pest eradication.

The book is designed to be read with ease but is nevertheless packed with stimulating scientific detail and leaves the reader absolutely clear that matters of extreme seriousness for the human future are at issue in our far south.

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