The book’s major theme is that, given all the environmental issues threatening life on Earth, the world will be “unlivable,” “uninhabitable” by roughly 2100. It will experience water shortages, famines, droughts, raging forest fires, massive floods, leading to conflicts in various parts of the world fighting for the remaining resources. Among the topics addressed are: greenhouse gas emissions; permafrost; deforestation; clean water scarcities; rising seas; melting glaciers; population growth; climate refugees; and several others. But, as the author points out, he just presents a summary of major deadly environmental threats. There are many more mankind will face that are not discussed in this book, issues ranging from air pollution, soil contamination to disposal of nuclear waste.