There is no question that humans have caused an environmental impact on the planet in many ways...and i personally think that the changes being implemented in our way of living and consumption of things is helping this, but like you said, the planet runs in cycles, and the idea that humans are the cause for the climatical changes that are occurring to such a dramatic effect is just hilarious to me. The Icecaps are melting because we're progressing towards the end of an "ice age" and we are entering a more temperate time on Earth...I'm no scientist, but one of my best friends is a climatologist and meteorologist (double majored) and when he tells me that what you see on the television about global warming is about as comical as watching an episode of Seinfeld...i believe him.
I just read the whole article I'm assuming the OP was referencing with his question...and it was such a shot in the dark theoretical scenario that i could write another one that says "Potatoes could become scarce...could seedless watermelon become blah blah blah blah blah...".