From the HuffPost, an interesting article by the head of UNICEF. See: To Reduce the Impact of Disasters, Increase the Focus on Children.  Here are some numbers that indicate how big this segment of the population is:

The number of children affected every year by disasters is projected to reach 175 million over the next ten years — a figure that will have nearly tripled since the early 1990s. Children represent more than half of all people affected by disasters, and not surprisingly, the children at greatest risk are typically the poorest and hardest to reach.