I do not think children should be completely shielded from the not nice bits of life but we do need to be careful about how we talk about current affairs in front of them and how we present the news in the media. The current trend to exaggerate possible consequences with even the liberal intelligentsia predicting the end of the world every time they do not get their own way affects whole economies. It is hardly surprising that such doomsaying can scare the living daylights out of children.
When I was a kid I somehow came across the prophecy of Mother Shipton that the end of the world would come in nineteen hundred and eighty one. I remember that I lied awake at night in abject terror for many weeks because I got it into my immature head that her prediction was sure to come true.
On the whole children can handle the truth if it is explained to them, calmly, by a caring adult. It is lies and fear-mongering that they have problems coping with as THIS ARTICLE on the BBC website proves.