When you buy some party balloons and eventually they escape into the sky or all the helium escapes, that helium is literally “escaping.” It is lighter than most of the atmosphere, so it goes up and up and up and basically out to the edge where our atmosphere becomes outer space. Ultimately, it would be very hard to get that helium back. Helium is also a noble gas element, the only way to make more if it is in a fusion reaction, something we usually try to do in very contained settings due to controls on nuclear weapons.
So all that means that each time some helium escapes, it’s basically gone for a good. It’s a non-renewable resource, even more so than a lot of the fuels that get called non-renewable. They are just a particular configuration of carbon which we can recreate biochemically if we need to–it just isn’t that energy favorable to do so.
Helium is an element, as noted, we can’t chemically create new elements. That’s the basic idea of chemistry, you’re manipulating the elemental building blocks. And helium is important, liquid helium is what is used in all sorts of industrial level cooling processes, particularly in MRI machines. It’s what makes the MRI magnets work.
Many decades ago, the US realized that helium was a precious resource and put huge amounts of it in a giant underground cavernous storage system. However, as time went by, this project was costing a fortune, so they thought to discontinue the project by dumping all the helium on the market. For decades now, they have been selling the helium cheaply, lowering the global market price and flooding the world with cheap helium. But all this time, the total amount of helium has been decreasing.
We still have plenty of helium, so don’t start hoarding helium tanks under your bed. But, if you’ve ever need an MRI, you can thank helium for that process. Every time you see a balloon drifting up to the sky, know that precious resource is disappearing from the earth forever.