It's a bad thing if you or your children and grandchildren die young because of it.
My bottom line is, if there is a 5% chance that the predictions are on average very roughly correct, and offered solutions are steps in a necessary direction, then we should take those steps. Where would you put your threshold for wanting to take action?
There's a chance of almost nil that a burglar will visit us one night, but we still lock the car and the house.