This leads to poor communication, and after a while everyone has retreated to extreme positions. The truth, we assume, was somewhere in the vast gap between these two figures. One of the important things mathematicians do is build tools for people to use in thinking about numbers. Risk comparison is an area where tools are needed, because of the trouble everyone has dealing with numbers much smaller than our normal experience. One number is a thousand times the other, yet both are much too small for us to deal with effectively.
Tools exist to think about and compare such tiny quantities.
The best of them is the logarithm, presented to us by John Napier, a Scottish nobleman, in 1614. Members of the general public probably don't know or don't remember what a logarithm is, but everyone has encountered logarithmic scales of measurement. We can do the same for risk. An event even less likely than that has negative risk magnitude. Just as an earthquake of magnitude 7.5 is 10 times as powerful as one of magnitude 6.5, increasing risk magnitude by 1.0 makes an event 10 times as likely to happen.