Sure. However, with climate change likely to make your ability to exist difficult within your own lifetime and definitely within the lifetime of your kids (if you have any), wouldn't it be wiser to choose to study engineering, biology, and the other hard sciences?

You can probably find some university or another willing to pay you to study ancient languages if you're a linguist and you also teach modern languages to pay your bills, but you'll have to learn those ancient languages on your own while getting your doctorate. Even if there is some course work for ancient languages, most of what you'll study (and eventually teach) as a linguist are modern languages.