Public policymakers are generally bad at addressing uncertainty, and worse at communicating it. This is partly because of the inbuilt short-termism in the tenure of elected officials. Pretending that outcomes are certain is often a perfectly viable short-term strategy, and, when the outcome is not as predicted, the policymaker has often moved on to another post.
Businesspeople have to think over a longer timeframe, and therefore tend to be better at coping with uncertainty than politicians. The responsible attitude to addressing and communicating uncertainty is to determine its parameters, and ensure that certainty is achieved wherever possible within them. For instance, there may be two possible outcomes of a course of action. You can be certain that you will know which one is occurring within six months, and you know how you will respond in either case. This is quite a lot of certainty which you can communicate. Even if matters are less certain, you can plan for the most likely scenarios and communicate that you have done so.
The level of uncertainty you can accept for yourself and your stakeholders will obviously vary according to the likelihood of the event and the seriousness of its results. Very unlikely events which would be very costly if they were to happen are obvious candidates for insurance. Other uncertainties should be the subject of clear and detailed contingency planning. The level of risk and its possible consequences should always be made clear to stakeholders.