She revealed her predictions during a recent phone interview with Bookengine.
But we’ll get to that all in good time.
I’d wanted to interview Julia for some time. She’s a hugely influential figure in children’s fiction and young adult books, certainly one of the most important of recent years without actually being a fiction writer herself. (We'll get to that too, so be patient!)
As well as her Guardian duties, she’s Puffin Books’ general editor of their mighty Modern Classics list.
Pick up a copy of Stig of the Dump, say, or Carrie’s War and there she is, introducing these great books of the recent past with insightful introductions and afterwords.
She has served as a judge - and continues to do so - on many book award panels. Over the years she has been involved in the Whitbread Children's Book Award, the Nestlé Smarties Book Prize and also the Guardian Children's Fiction Prize. She is a co-founder of the Branford Boase Award for an outstanding novel for young people by a first-time writer.
|A fabulous guide to children's and young adult fiction|
As I intimated earlier, Julia has never written a children’s book herself. Why?
Her first job was working as children's book editor on the Times Literary Supplement in the 1970s before working as a book editor at Puffin Books and at Hamish Hamilton children's books in the 1980s. Eventually she moved into freelance book reviewing.
I asked Julia what drew her to children's literature in the first place and she replied in an instant: Rosemary Sutcliff.
"I read history at university and I absolutely loved her books. I also liked authors like Philippa Pearce and books like Emil and the Detectives.
"I absolutely loved the sense of escapism books gave me. That feeling of wonder, of realising you could find out what someone else is thinking.
"I am not someone who read for plot as a child. I was never as concerned about what happened next in the story. I always read for feeling, for the emotional response a book caused in me."
I asked Julia about her thoughts on the importance of reading to children and young people, particularly for today's youngsters who have so many more ways to spend their time, so many more distractions than previous generations had.
She said: "I'm not sure that it's reading, actually, that's important. I think it's stories. Two of my children are dyslexic so reading is difficult. I like books myself, the book is a good form, it works very well. But I don't think it matters if you get these stories through another medium, such as audio books.
"So rather than get hung up on books, it's the stories that are important.
"Stories should be fun, they should be exciting and funny. They're about disinhabiting yourself and inhabiting another character."
Julia said she was annoyed by what she calls 'lookalike' fiction, such as the overwhelming number of books about vampires inspired by the success of Twilight.
"It's driving out originality. I'm not against it, but I've had enough of it. Publishing is a curious business, it's got to make money, but it's not prepared to take risks. And without that it's difficult for originality to come through.
"Yet I think it is original voices that people want.
"And for writers today getting published isn't difficult, it's staying published. People aren't given time to build a reputation."
She says authors like Jacqueline Wilson (whom Julia first published in the 70s) and Philip Pullman were published for 10 years before they became major successes.
I asked Julia what she thought about the popularity of self-publishing among first-time authors thanks to the advent of e-readers. Was this a route she would recommend for the serious writer who was finding it difficult to get published on the conventional agent-publisher path?
"I don't know enough about it. It's a very speculative question.
"I believe in the democratisation of all these things, but at the same time I do feel very strongly that books need to be edited."
From the days of Robert Cormier and S E Hinton through to today's leading writers such as Anthony McGowan and Melvin Burgess, young adult fiction has always ventured into dark and disturbing areas. Was there any subject matter Julia believed was unsuitable?
"Violence is off-limits. I read a book this morning and it starts with 60 pages of a child being beaten up. That angered me.
"There is nothing wrong with death in children's books, but it has to be handled in an emotionally sophisticated way."
I asked her what made a book worthy of Puffin's Modern Classics list? How did you define a classic?
She replied: "I guess it's books that have long-lasting values. You look at something like Charlotte's Web and you can feel it."
And what are the classics of the future? Which contemporary authors will we still be reading?
She believes it's irrelevant how much a publisher pushes an author or how many copies a book sells. That's no guarantee of longevity.
"It's very often the quiet books that last," she said.
So, if she had to stick her neck out, who did she believe was headed for classic status?
|Patrick Ness's Carnegie winner is likely to last, says Julia|
Although she's not a fan of fantasy, Julia earmarked Philip Reeve's Mortal Engines series as one that would last.
"Geraldine McCaughrean should still be read. She's an exceptionally talented writer - she writes a different book every time. I also think How I Live Now by Meg Rosoff will still be read 20 years from now.
"But, you know, not all authors write good books all the time. Philippa Pearce, for example. Not all of her books are good."
So, there you have it. If you have first editions of anything by Patrick Ness, Philip Reeve, Geraldine McCaughrean or Meg Rosoff, it's probably wise to take very good care of them. Chances are they will be worth something in the years ahead.
• Many thanks to Julia for sparing an hour on a Sunday morning to speak to Bookengine.