Important end-of-the-world information: You can start a fire using only water and plastic wrap. Which makes plastic wrap an essential element for your Ecopocalypse Preparedness Kit, since you’ll probably be using that Sterno to keep feral animals and people away from your dwindling supplies.
Mind you, making fire from water is a pain in the ass, takes forever, and contains the seeds of its own destruction (in the video, you’ll see that the plastic wrap develops a leak almost as soon as a tiny flame starts up). But in principle, it’s pretty simple. You collect the water in a piece of plastic wrap, making a ball of water with as few air bubbles as possible. Then you use that water ball to focus light onto paper, like an elementary-schooler frying an ant. Et voila: You live one more day in a cruel post-apocalyptic wasteland.
Unless you’re in the American Southwest. Then you probably won’t have any water to build a fire with. But hey — if you live on the coasts, you’ll have more than you could possibly use!