"The central tenet of this book is that we must rapidly reacquaint ourselves with global environmental systems and how we depend on them. The long-term good health of populations depends on the continuing stability and functioning of the biosphere's ecological and physical systems. The book is a timely reminder that the debate on global warming is shifting from a "will it or won't it happen" question to a recognition that some effect is inevitable. Even if substantial reductions in greenhouse emissions were to be made the planet would continue to warm for at least the next 50 years and sea levels continue to rise for hundreds of years, because of the time it takes for basic global systems to reach a new equilibrium. Now we urgently need to understand what the likely impacts of climate change will be and which populations are most at risk, so that global society can respond appropriately."