Six Degrees by Mark Lynas.

I've just finished reading Six Degrees by Mark Lynas. Apart from feeling thoroughly depressed as a result, I am, after digesting the final chapter, determined to cut down my carbon consumption. I suppose a start would be to do what Ian Hopkinson has done: and utilise greener energy sources. As the book says, it is more important than anything else.


Mark Lynas realised that since he lived near Oxford, he had access to a wealth of information about global warming in the Bodlean Library. He decided to go through all the peer-reviewed literature on the subject, and summarise what scientists have determined would be the possible effects of a one degree rise in average global temperature, and then a two degree rise and so on up to a six degree rise. The first degree rise is inevitable, he says. This will mean we will have fewer species of life sharing the planet. Atolls and other low lying land will disappear, and some of the temperate and tropical mountains will lose their ice. Hurricanes will become more widespread.

At two degrees there is further loss of land from low-lying areas as the oceans rise - including a large number of coastal cities. Loss of ice from South American glaciers and snowpack will mean drought along the western side of the Americas. There will also be increased incidence of lethal heatwaves - as in Paris 2003 when 210,000 people died. The biggest effect will be felt in India as agricultural production will diminish, and the monsoon strengthens and there will be increased flooding. Mark Lynas surmises that 2 degrees will be survivable, albeit with loss of biodiversity.

It is at three degrees that things get bad. Using the model set by fossil evidence from the Pliocene, he predicts superhurricanes with faster, more powerful winds, serious fertility and drought problems in the west of the US, while the eastern seaboard floods. In Europe too, the frequency and intensity of storms will increase, while south of the Alps there will be desertification. The main rivers in Asia (e.g Ganges and the Yangtze) initially flood but then diminish as the Himalayas lose ice. Crop yields start to decline in the tropics due to heat which will bring widespread starvation, so the crop range will shift towards the poles. This will lead to climate refugees and a new philosophy of blame.

Perhaps the most catastrophic thing of all is that at three degrees there could be positive feedback, particularly in places like the Amazon. The forest will produce more carbon dioxide as it becomes warmer which will lead to greater temperature rises, drought, wild fires and eventually desertification of the whole basin. The picture he draws even at three degrees temperature rise is terrifying.

At four, five and six degrees the situation becomes worse. The world is subjected to alternate flood and drought, and as the temperature rises more positive feedback comes into play. At four degrees, stored methane is released from the tundra, which is an even worse greenhouse gas, at five degrees methane hydrate is released explosively from subsea continental shelves causing Tsunamis, and at six degrees even oceanic carbon fixers are dead and there is runaway warming. In each case there is palaeoclimatic evidence from rock strata. The six degree model comes from the mass extinction at the end of the Permian 251 million years ago when 95% of the species on the world were wiped out.

Mark Lynas describes each scenario very vividly, with some sequences read like a thriller, and I have a feeling that Mark Lynas enjoyed writing this book, despite its serious and dismal message.

At the end he says that it is essential that warming is halted at 2 degrees, and for this to happen green house emissions must peak within the next eight years (2015). After that they must decline by 90% by 2050. In order to achieve this he suggests a 'contraction and convergence' agreement so that everyone on the planet has the same emission per person.

Practically, this means halving the distance people drive, increasing fuel economy, increasing fuel efficiency and generally living less consumptive lifestyles. I suppose each one of us needs to look at our lives and see what we can do. However, I think little is going to be achieved unless the government helps, because without their incentive, most of us are going to sit back and do nothing.

I was given this book by an environmentalist in Perth.