Like many people, I've long wondered about the safety of genetically modified organisms. They've become so ubiquitous that they account for about 80 percent of the corn grown in the United States, yet we know almost nothing about what damage might ensue if the transplanted genes spread through global ecosystems.

How can so many smart people, including many scientists, be so sure that there's nothing to worry about? Judging from a new paper by several researchers from New York University, including "The Black Swan" author Nassim Taleb, they can't and shouldn't.

The researchers focus on the risk of extremely unlikely but potentially devastating events. They argue that there's no easy way to decide whether such risks are worth taking — it all depends on the nature of the worst-case scenario. Their approach helps explain why some technologies, such as nuclear energy, should give no cause for alarm, while innovations such as GMOs merit extreme caution.