Comment: This line caught my eye: "“Half the world’s population gets food as a result of fertilizers… and if that’s removed from the field for some crops, [the yield] will drop by 50 per cent,” he explained."
So, if half of world food is produced with fertilizer, and if the fertilizer is removed then that half of production is halved. So, we lose 25% of food production. That of course assumes no fertilizer, which isn't the case, so it would not be that bad, but you get the point. Worst case scenario, 25% of the world's population goes hungry.