Hello Wakalix. A creator is necessary because there is no other way that the universe can possibly exist. Think about it, the universe is so vast and creation is so unbelievable that there HAS to be a creator somehow. As an atheist I didn't believe it either like you don't but, it's the truth.
What evidence is there that scripture can be taken as a science text book? You mean besides faith? Well for one the Bible has predicted things since before Christ came to the earth. Like I said, it proved the world was round before Christopher Columbus proved it. It also proved in Genesis 3:15 that both men and women possess the seed of life (Sperm and the Egg). This wasn't discovered by science until the 17th century. These are just some of the things the Bible has proven.