Book explains the consequence of global heating for each degree.

Our Final Warning: Six Degrees of Climate Emergency

In the year 2007 Mark Lynas wrote the book Six Degrees: Our Future on a Hotter Planet. He organized the book into six chapters — one for each degree (Celsius) increase in the earth’s temperature over the pre-industrial baseline. Based on his research and reading, he provided a summary of what conditions may be like for each temperature. His book pulled no punches. He described just how terrible conditions will be as the Earth’s temperature rises.

Our Final Warning: Six Degrees of Climate Emergency

In 2020 he issued a second edition of the book with the expanded title Our Final Warning: Six Degrees of Climate Emergency


One of the key differences between the two books is that Chapter 1 in the first edition predicts what the world will look like with one degree of warming. In the second edition one degree has happened — it is in the history books. It turns out that the 2007 projection was quite accurate. For example, in it Lynas talks about slow-moving hurricanes dumping immense amounts of rain, and the likelihood of massive wildfires in the American west. Since he made those predictions Hurricane Harvey has dealt devastation to the Gulf Coast of the United States, and wildfires in the west have swept California and Oregon.

The following is from a summary of the current edition.


At one degree – the world we are already living in – vast wildfires scorch California and Australia, while monster hurricanes devastate coastal cities. At two degrees the Arctic ice cap melts away, and coral reefs disappear from the tropics. At three, the world begins to run out of food, threatening millions with starvation. At four, large areas of the globe are too hot for human habitation, erasing entire nations and turning billions into climate refugees. At five, the planet is warmer than for 55 million years, while at six degrees a mass extinction of unparalleled proportions sweeps the planet, even raising the threat of the end of all life on Earth.