Food/Abundance of agricultural resources
The world's agricultural system currently produces ample food for everyone — over 2700 calories per person per day [1]. Agricultural productivity has consistently grown faster than population, with a 17% increase in calories per person in the past 30 years despite a 70% increase in population.
Food production depends on time, incentive, genetic diversity of seeds and livestock, soil (or nutrients), water, land and access to technology and to information. Of these, none has a hard limit except for land —
This planet currently has 138 trillion m2 of arable land 
for growing crops and 335.7 trillion m2 of pasture for raising livestock [2]. This can be greatly expanded if necessary by irrigating deserts and introducing sustainable farming practices that rehabilitate soil. (For example, 3 billion m2 of land in Niger was reclaimed for farming recently[3].)
However, improving food supply has much more to do with increasing the yield of existing farmland than creating new farmland [4]. This is because the system of agriculture makes a huge difference to the amount of land needed; the average Canadian requires over 12,000m2 [5], while permaculture systems regularly produce enough food for a person on less than than 400m2. If we could increase the average productivity of our 138 trillion m2 of farmland to just one-tenth this level, we could grow enough food for 34.5 billion people, about five times the current world population.
