Since the Fukushima nuclear crisis occurred, there has been widespread speculation about the global impact of the disaster. Fortunately, a team of Stanford researchers has thrown their brains at the problem, and the answers are fairly reassuring.
Using 3D global atmospheric models developed over the last 20 years, the team was able to predict the likely transport of radioactive material around the globe and how it would affect the health of the planet's population. Their best estimates suggest that, in total, we could expect to see 130 deaths as a result of the incident and 180 extra cancer morbidities over a longer time period.
Those figures include Japan, however. The US was predicted to experience somewhere between 0 and 30 cancer morbidities as a result of the disaster. Those final predictions are so broad because the resulting radionuclide concentrations are so low in the US -- so most likely the number will actually be extremely small. In other words: no need to panic. [Stanford]