Some of these events, such as freeing all slaves worldwide, are good events, while a supervolcano eruption could theoretically kill half of humanity by blanketing the world in ash and causing a volcanic winter by blocking sunlight. Others, such as ending oil dependence and no longer killing animals to eat, would be a mixed blessing. Pearl introduces each event with a scenario showing how it might occur. He also rates how likely it is each event will occur in this century along with how plausible it is, how scary the event is, and whether or not it's worth changing our habits to avoid the event. Some of these events are more plausible than you might expect, such as creating a dinosaur park. (Pearl suggests this could be done by selective breeding and genetic manipulation, since actual dinosaur DNA would be too badly damaged to use.) In my opinion, some of the topics he discusses, such as the end of British royalty, seem frivolous compared to the extinction of all fish or learning aliens do exist.
Although some of the scenarios Pearl discusses would be catastrophic if they ever occurred, Pearl attempts to assure us in an Epilogue that the future isn't lost. Humanity may not always exist in its current form, but our descendants would be better adapted for their environment. We may be able to avoid demise if we're able to colonize space. We also know too little about the universe to know what will happen in the far future. He stresses that he wants to convince us the future is worth it:
Some of the horrors I've outlined won't be avoided, and some will. Some of the wonderful things I've predicted won't happen, and others will....If we fundamentally don't believe in a future at all, I'm pretty sure of one thing: it'll be more horror than wonder.
As a science fiction writer, I try to predict the future even knowing how unlikely it is I'll be right. It's always interesting to read what other futurists think. Do you find these kinds of books useful for your own world-building? Free free to share your thoughts in the comments.