I know many here are already doing it. But for those who aren't, what is stopping you? Post it here and maybe more experienced gardeners can offer advice.
I myself do not have lots of land but I've found a way to pack lots of food in a small space. You have to start somewhere, I would at least start with getting your seeds now. If you have beans and rice stored, then you have your calories, but even just growing some high nutrient greens in your window will help keep you healthy so you aren't surviving just on the limited nutrients offered by beans and rice.
And here is something many people probably haven't considered. You can raise meat rabbits inside if need be. So if you are in an apartment, meat rabbits, high nutrient greens in the window, and a good supply of beans and rice is better than nothing. The rabbits will also give you clean pellet fertilizer for your little garden. Raising worms in a plastic bin will also give you fertilizer for basically free once set up.
There are lots of other options for different needs. I can't urge it enough, grow food now. Also, start canning too. When food comes in, either from your garden or if you catch a good sale at the store, preserve it now for hard times later. Canning your meats insures you have meat even if the electricity goes out. Buy your canning supplies now, while they are available, they are one of the first things to vanish from shelves when there is a scare. Same with seeds. Buy now.
Also know that some food producing plants are perennials. That means if you take care of them correctly at the end of the growing season, they will come back stronger and with better yield in the spring. Today I dug up my bell pepper and jalapeno plants and prepared them for the winter. here's how:
https://www.youtube.com/watch?v=nsdmD54Bsu4
Yes! Asparagus, ginger, tumeric, all keep going. Peppers and eggplants too. I overwinter mine. I currently have a 3 year old tabasco still producing.
Chives and garlic chives are survivors for me, they become houseplants during the winter.