Impacts, like hurricanes related to global warming, may make the headlines for a day or two.

A couple of experts may argue about their significance, leaving everybody confused.

The TV, radio, and press like a good story that has obvious health effects that people can relate to.

This is not to say they sensationalise everything, but they do like to make the impacts clear - "human stories".

They like a body.

What makes a good risk story? There are five things to look for.

1. The effects have to appear familiar and close to people.

2. The impacts should stir up emotions of fright and fear.

3. The group affected should be important.

4. It should not threaten other major interests.

5. It should be kept on the agenda to satisfy people's appetite.