I'm always skeptical about predictions of a coming food shortage. It's been predicated for the last 200 (Malthus' An Essay on the Principle of Population was published in 1800), and it hasn't happened yet.
It doesn't prove it's impossible, it proves that the original predications were well off. Back then people though 1 billion people were enough to worry about the lack of food. We're at 8ish billion now and people are still worried. The world survived.
