The contention seems to originate from this frame:
"We are actually losing a large part of the most productive food producing areas of the world, we're going to lose them over three or four decades, a large proportion of the population is going to die in that period"
Do you mean that 4+ billion people are going to die from hunger in the next 30-40 years?
I don't think the podcasters (or majority of the listeners for that matter) would agree with that.