Six degrees – Our Future on a Hotter Planet, is the title of Mark Lynas’s 2007 book (this review is from the updated 2008 version) which seeks to give a broad overview of what mainstream scientific opinion (ie those which have appeared in reputable peer reviewed journals) suggests the world might look like over the next century with variable amounts of warming from pre0industrial temperatures. As title of the book suggests, Lynas looks as what is likely to happen with 1 degree of warming, 2 degrees and so on.
Overall, the book is well researched and written, condensing a vast amount of scientific literature into 275 pages with clear references to the original material Lynas has cited. The prose is generally very straightforward, and consequently this is a book which anyone can pick up and read, which I’m sure was Lynas’s intention: seeking to present a simple but generally accurate picture of what science says a warming world will probably be like, and some of the reasons why this is likely to be enormously detrimental to most forms of human and non-human life on Earth.
While Lynas does mention the potential positives of a mildly warming world such as increased growing seasons and crop production in Russia, the Ukraine and Canada, these are heavily outweighed by rising probabilities of drought, water shortages (largely from glaciers melting away), floods, mass crop failures, loss of biodiversity and potential social and ecological collapses. Lynas does a good job in this respect of respecting regional differences, but connecting these regions into a broader global picture.
Particularly frightening are the predicted prospects of a world more than two degrees warmer than the pre-industrial global mean, as not only are the effects of such climactic change going to be more severe, but there exists a reasonable chance that once warming reaches this oft-discussed tipping point that natural positive feedback loops kick in which alter the global climate so as to reach the kind of steady-state seen in other global extinction events, a six degree rise in temperature. Lynas does a very good job in explicating how some of these effects may arise, and in spelling out the kind of drastic changes they would entail for the planet’s climate.
While generally I think the book has been well though out and written, there were a few bits of linguistic sloppiness which frustrated me. Describing a world which is six degrees warmer than 150 years ago as ‘the ultimate apocalypse’ merely gives ammunition to those who seek to decry Lynas as a false prophet of global doom. If the apocalypse is the end of the world what exactly the ultimate apocalypse? The sun going supernova? The Galaxy collapsing into a black hole? No… a similar amount of warming to other mass extinction events such as the Permian. Six degrees of warming may well see the extinction of the human species (as Lynas states) but this is very different from it being the ultimate apocalypse, and this kind of exaggerated statement is the only thing that really stops me from saying that this is a book that everyone should read. Which is a shame, because most of it isn’t alarmist nonsense, but a very clear and well written summary of the scientific evidence surrounding our probable future climate.