Some children react with worry over things that they hear (and most of all, see) on the daily News. If a child often expresses alarm or concern about what they hear from News bulletins, this may be a sign that they have a higher level of anxiety. (The majority of children have mechanisms to shrug off things which in their minds are meant for adults - at least, to some extent.)
Commercial stations are especially oriented towards the dramatic aspects of current events and the footage and commentary can be quite graphic though.
Visuals of people being hurt or endangered, or something which is sudden, shocking, or looks as if it could happen in your local environment are the most worrying even for the average child. This type of event might need careful explanation. It is important to outline to your child why those kinds of things are (probably) unlikely to happen in your neighbourhood, and why. If they are likely to happen, the child will need to hear your sensible plans to keep everyone safe. They will need to understand why those plans will work for your family, and where they fit in.
Your child needs an age-appropriate understanding of particular patterns relevant to your local environment (such as a river which floods, or bushfires) – but they do not need to hear wall-to-wall coverage of adult alarm. There are many things “stealing” childhood these days…our children don’t need yet one more.