We all have our own perspectives on climate change. Most of us probably see it as a problem to be faced by ourselves, our children and our grandchildren. If we are optimists, we may hope that within this time span humanity will have found ways of stabilising greenhouse gas concentrations and, consequently, the Earth's climate will start to return towards its pre-industrial state. Undoubtedly there will be problems to be faced in the meantime, while mitigation measures are put into place, but, given enough time and the willingness to act, we may hope that we can put things right eventually.

David Archer's book, The Long Thaw, could be read as a polemic against such complacent thinking and makes a strong case for taking urgent action on greenhouse gas emissions. His central thesis is that human-generated CO₂ has a very long lifetime in the atmosphere. While much of this additional atmospheric carbon gets absorbed by the oceans relatively quickly (on a timescale of a few hundred years), further reduction through neutralisation by ocean carbonates and by silicate weathering takes much longer. Archer has estimated that 17–33% of the total fossil fuel carbon burned will still reside in the atmosphere after 1000 years. Even after 100000 years, 7% remains. While these figures are derived from carbon cycle models that will, inevitably, be improved as we learn more about the workings of the Earth system, we can be fairly certain about the long timescales involved. We need to recognise that burning fossil fuels now is committing us not just to a short-term ‘blip’ in climate, but to The Long Thaw of the title.

Archer argues his case well. As a palaeoclimatologist, specialising in the operation of the global carbon cycle on geological time scales, he is well placed to present the evidence for the need to take the long view and to argue that we need to restrict our total carbon emissions if we are to avoid long lasting, potentially dangerous climate change. This long term perspective sets the book apart from other recent offerings on global warming. Having said that, Archer starts fairly conventionally, with an exposition of the physics behind the greenhouse effect, an examination of recent observed climate change and a very brief summary of Inter Governmental Panel on Climate Change (IPCC) projections for the next century. He then leads the reader on a journey into the Earth's past, looking at evidence for climate variability on timescales from millennia (the Holocene), through hundreds of millennia (glacial cycles) to millions of years (geological time), and shows how examining evidence for past climate change can help us to understand the workings of the global carbon cycle on long time scales. In the final part of the book, Archer demonstrates how this understanding can be applied to the problem of forecasting the long term fate of human generated CO₂ and the consequence of such forecasts for the prediction of climates into the deep future. An epilogue explores economic and ethical issues arising out of the science described within the book. Here the author is entering contentious territory, in which scientists, economists and politicians argue endlessly about the relative costs and benefits of various strategies for tackling climate change. Archer makes some interesting observations that are of relevance to this debate. In particular, he shows that carbon capture and storage, either in the oceans or in stable geological formations, is no panacea for avoiding the long lasting effects of climate change that he discusses in the book. However, it is doubtful that this observation will have much impact on policy. Carbon capture and storage could reduce the peak CO₂ concentrations over the coming couple of centuries and the focus of almost all policy decisions is on timescales even shorter than this. Decisions will probably be made on short term economic grounds, but the ethical question remains – what right do we have to commit future generations to living with long term climate change in order that we may enjoy the short term benefits of burning fossil fuels?

The book does not have a particular polar focus, but Archer emphasises the importance of the polar regions in the global climate system and in the global carbon cycle. He discusses the role of methane hydrates in polar marine sediments and in permafrost as potential amplifiers of climate change through the carbon cycle. A notable omission from the book is any detailed discussion of the contribution of biological processes in the high latitude oceans to the carbon cycle. Indeed, the author's emphasis throughout is on the physical pathways in the oceanic carbon cycle. The polar regions also feature in a short chapter on sea level rise, which summarises our current understanding of how two major ice sheets – Greenland and West Antarctica – will respond to a warming climate. Archer emphasises that current predictions of future sea level rise contain considerable uncertainties as a result of our imperfect understanding of how these ice sheets behave. There is a clear need for further research.

I found the book quite readable and felt that it usefully filled some gaps in my understanding of the global carbon cycle. However, I did find the text annoyingly repetitive in places. This seems to be a deliberate choice by the author to ensure that he gets his message across to all readers, even those who just skim through the book. Indeed, he almost encourages such behaviour by inviting the impatient reader to skip the detail contained in chapters 4–6 and rejoin the text at chapter 7. This is a strange invitation in a book that is already quite short, and begs the question of who the intended audience is. Presumably Archer wants to get his message across to politicians and their advisers, and recognises the importance of brevity when addressing this group. However, I fear that he may have overestimated the appetite of this group of readers for scientific detail. While the book only requires a very basic understanding of physics and chemistry, the author's liberal use of equations and chemical formulae may put off some general readers. I hope that this is not the case, because the ideas expounded in the book are of great importance to the debate on climate change and deserve to be more widely appreciated. Let us hope that Archer's message becomes widely understood and acted upon before we find that we have already committed ourselves to damaging (and potentially irreversible) climate change.