We also know that we produce more than enough food in the world to feed everybody. But there are redistribution problems, and about one-third of all food is lost at the transformation stage. So there is a lot of slack to be picked up there; but obviously, decreasing production could be a major factor.
We're also looking at the issue of nutrient depletion. Climate change, CO2 changes in the air, are having an impact on the nutrient content of food. Some cereals have about 10 percent less protein, and they have less minerals and less vitamins. So it's not just a question of how much food, but also the quality of that food.
Unpredictability like it's sunny now but will rain later, I think we can handle, but just how unpredictable are they talking about? Do we have to prepare for hotter summer every year? Colder winter? More terrible flooding, storms and hurricanes? If it's the latter then that's bad, and I'm not sure how much longer we can survive the next big natural disaster.