by Chris Turney 2008 Macmillan ISBN 13: 978-0-230-55382-8 ISBN 10: 0-230-55382-6 234pages £15.99 HbkVery clear explanations, very good details and a very clear style. Knowing about previous climate states is the only way to understand how devastating an increase in global temperatures can be. We have only seen about 0.7oC increase so far. Two degrees increase we can’t escape now even if we halted all carbon emissions instantly. Some experts seem to think increases of 5oC or even 6oC are tolerable – in some cases perhaps because they don’t want to accept that major changes in lifestyles are necessary. Apart from the risk of triggering unstoppable runaway releases of carbon, increases of this size are comparable with those in the past which brought catatrophic changes to the planet.