When wondering if something is globally understood, my first instinct is to look to interfaces that people are used to, globally, e.g. Windows. There, they do use arrows, but intriguingly enough they aren't placed next to items (where they draw too much attention to themselves and you might not know which row they represent) but above them. See the "Startup impact" sorting in the screenshot below:
But Windows also offers two alternatives for Explorer, showing that it might not be the first place people look inside applications, at least. They also offer Sort (and View) options on right-click, though most users would not expect custom right-click menus within their web browser. And they have a button/drop-down dedicated to sort options:
Note the icon use does have arrows, but it has two arrows -- the arrow next to text indicates "drop down" while the two-way arrow above text, next to a grid, indicates "sorting".
I've left this answer open as a community wiki in case anyone wishes to edit it, perhaps providing better examples.