“It may seem impossible to imagine that a technologically advanced society could choose, in essence, to destroy itself, but that is what we are now in the process of doing.

I think it's the kind of issue where something looked extremely difficult, and not worth it, and then people changed their minds. Take child labor. We decided we would not have child labor and goods would become more expensive. It's a changed preference system. [...] If it's a problem like that, then asking whether it's practical or not is really not going to help very much. Whether it's practical depends on how much we give a damn.

The disintegration of one of the planet’s remaining ice sheets is often held up as the exemplary catastrophe. The West Antarctic ice sheet is, at this point, the world’s only marine ice sheet, meaning that it rests on land that is below sea level. For this reason it is considered particularly vulnerable to collapse. Were the West Antarctic or the Greenland ice sheet to be destroyed, sea levels around the world would rise by at least fifteen feet. Were both ice sheets to disintegrate, global sea levels would rise by thirty-five feet. It could take centuries for either of the ice sheets to disappear entirely, but once disintegration got under way it would start to feed on itself, most likely becoming irreversible.

At the current rate of emissions growth, CO2 concentration will top 500 parts per million--roughly double preindustrial levels--by the middle of this century. It is expected that such an increase will prompt a string of disasters, including fiercer hurricane, more deadly droughts, the disappearance of glaciers and the melting of the Arctic ice cap, and the inundation of the world's major coastal cities.