If Noah did warn the world, the world obviously chose to ignore his warnings, because the Bible teaches that the world was taken by surprise when the flood came.
Thanks Blondie - interesting read.
The writer misses the same point. Noah was told to take food for only the animals and 'you' - him and his family.
God obviously decided that they'd be the only ones who would survive, so what would be the point in 'warning' people even though if any repented there was no food in the Ark for them?