Sun

This is something mostly out of our control. The sun will do as the sun pleases. Rampant air pollution could negatively impact the amount of solar radiation reaching plants. Still, the real threats here are supervolcanoes and nuclear winter, causing mind-boggling levels of smoke and ash to enter the atmosphere, blocking out sunlight for years or decades.

In our food system, we face various issues — waste, heavy reliance on just-in-time delivery, access to adequate water, access to sufficient solar radiation.

Waste

It might be shocking to learn that approximately 1/3 of food is lost to waste globally. This happens throughout the supply chain and in our homes and businesses. In fields, crops can be lost to fungus/pests/weather damage/damage during harvest/inability to harvest in an adequate time frame. Damage can occur in transit from the fields to processing plants, from plants to warehouses, from warehouses to retail outlets. Then food gets purchased and not consumed, either neglected in your refrigerator (let's be honest, yours needs to be cleaned out, doesn't it?) or prepared and discarded. One way to drastically reduce this would be to produce food much closer to the final point of sale, another to be more aware of the issue as consumers and try to eliminate the waste on our end by being more conscientious about our portions and by using as much of a vegetable, fruit or animal as possible (an easy way being stocks and soups).

Supply chain

Just-in-time delivery isn't just an issue for food; it is an issue for nearly all sectors and goods and is something we take for granted and should not. It is cheaper for an entity to order a good just before it will be needed than to maintain a warehouse full of goods to draw upon as needed, even when this might mean shipping something from China to Indianapolis by air in 1-3 days.

The problem here is large population centers often have, at best, days of food available for consumption, and in fact, the world only has 2-3 months of food reserves. One method to address this is to begin maintaining warehouses of shelf-stable food near large population centers. Another is to grow the food considerably closer to the end-user to build better flexibility into the supply chain and allow for quicker delivery of goods.

Water

As I addressed above, one solution to adequate water is accessing aquifers; however, as illustrated above, this is already causing issues in the U.S. and virtually everywhere else. Crops require obscene amounts of water, for example, you need an input of roughly 594,000 gallons of water for 1 acre of corn with a yield of around 200 bushels (11,200 pounds of corn). Now obviously this water doesn't cease to exist, but you do need to bring it in one way or another, often we mostly rely on rainfall, but when rain is scarce, we tap those aquifers. One way to drastically reduce the amount of water needed is by having a closed system.

Sun

Again, the sun will do what the sun wants, but we do have grow lights now (and technically, you can use orbital mirrors to reflect more sunlight on a given area as was attempted with the Znamya project). While the sun is the cheapest option, grow lights allow many benefits such as controlling the duration and intensity, allowing you to grow indoors or even in space habitats in the future for outposts on the moon or Mars.

An interesting approach and part of a viable solution is to look at growing indoors is mostly enclosed systems.

Three entities are doing this right now that I'd like to use as examples.